ML072080217
| ML072080217 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 12/08/2005 |
| From: | Packer D, Vitaliano J, Zetlin C US Dept of Commerce, National Marine Fisheries Service, US Dept of Commerce, National Oceanographic and Atmospheric Administration |
| To: | Office of Nuclear Reactor Regulation |
| Davis J NRR/DLR/REBB, 415-3835 | |
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| Download: ML072080217 (73) | |
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a q14 NOAA Technical Memorandum NMFS-NE-175 of Essential Fish Habitat Source Document:
Little Skate, Leucoraja erinacea, Life History and Habitat Characteristics U. S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Marine Fisheries Service Northeast Region Northeast Fisheries Science Center Woods Hole, Massachusetts March 2003
Recent Issues in This Series:
155. Food ofNorthwest Atlantic Fishes and Two Common Species ofSquid. By Ray E. Bowman, Charles E. StillweU, William L. Michaels, and Marvin D. Grosslein. January2000. xiv+ 13 8 p., I fig., 7 tables, 2 app. NTIS Access. No. PB2000-106735.
156. ProceedingsoftheSummer Flounder Aging Workshop, 1-2 February 1999,Woods Hole, Massachusetts.ByGeorge R. Bolz, James Patrick Monaghan, Jr., Kathy L. Lang, Randall W. Gregory, and Jay M. Burnett. May2000. v + l5p.,5 figs.,
5 tables. NTIS Access. No. PB2000-107403.
157. Contaminant Levels in Muscle of Four Species of Recreational Fish from the New York Bight Apex. ByAshokD.
Deshpande, Andrew F.J. Draxler, Vincent S. Zdanowicz, Mary E. Schrock, Anthony J. Paulson, Thomas W. Finneran, Beth L. Sharack, Kathy Corbo, Linda Arlen, Elizabeth A. Leimburg, Bruce W. Dockum, Robert A. Pikanowski, Brian May, and Lisa B. Rosman. June 2000. xxii + 99 p., 6 figs., 80 tables, 3 app., glossary. NTIS Access. No. PB2001-107346.
158. A Framework for Monitoring and Assessing Socioeconomics and Governance of Large Marine Ecosystems. By Jon G. Sutinen, editor, with contributors (listed alphabetically) Patricia Clay, Christopher L. Dyer, Steven F. Edwards, John Gates, Tom A. Grigalunas, Timothy Hennessey, Lawrence Juda, Andrew W. Kitts, Philip N. Logan, John J. Poggie, Jr.,
Barbara Pollard Rountree, Scott R. Steinback, Eric M. Thunberg, Harold F. Upton, and John B. Walden. August 2000. v
+32p.,4figs., I table, glossary. NTIS Access.No. PB2001-106847.
159. An Overview and History ofthe Food Web Dynamics Program ofthe Northeast Fisheries Science Center, Woods Hole, Massachusetts. ByJasonS. Link and Frank P. Almeida. October2000. iv+60p.,20 figs., l8tables, I app. NTIS Access. No. PB2001-103996.
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9 figs., 5 tables. NTIS Access. No. PB2001-106502.
161. Demersal Fish and American Lobster Diets in the Lower Hudson- Raritan Estuary. By Frank W. Steimle, Robert A. Pikanowski, DonaldG. McMillan, ChristineA. Zetlin, and StuartJ. Wilk. November2000. vii + 10 6 p., 2 4 figs., 51 tables.
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162. U.S. Atlantic and Gulf of Mexico Marine Mammal StockAssessments- 2000. Edited by Gordon T. Waring, Janeen M. Quintal, and Steven L. Swartz, with contributions from (listed alphabetically) Neilo B. Barros, Phillip J. Clapham, Timothy V.N. Cole, Carol P. Fairfield, Larry J. Hansen, Keith D. Mullin, Daniel K. Odell, Debra L. Palka, Marjorie C. Rossman, U.S.
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I table. NTIS Access. No. PB200 1-103542.
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Loomis, Michael R. Ross, and Scott R. Steinback. December 2001. viii + 12 9 p., I fig., 81 tables,4 app. NTIS Access. No.
PB2002-108348.
166. Report on the Third Northwest Atlantic HerringAcoustic Workshop, University ofMaine Darling Marine Center, Walpole, Maine, March 13-14,2001. By William L. Michaels, editor and coconvenor, and Philip Yund, coconvenor.
December2001. iv+ 18p., 14 figs.,2app. NTIS Access. No. PB2003-101556.
- 0. c~pf 1.
NOAA Technical Memorandum NMFS-NE-175 z This series represents a secondary level of scientific publishing. All issues employ thorough internal scientific review; some issues employ external scientific review.
Reviews are - by design -- transparent collegial reviews, not anonymous peer reviews. All issues may be cited in formal scientific communications.
Essential Fish HabitatSource Document:
Little Skate, Leucoraja erinacea, Life History and Habitat Characteristics David B. Packer, Christine A. Zetlin, and Joseph J. Vitaliano National Marine Fisheries Serv., James J. Howard Marine Sciences Lab., 74 Magruder Rd., Highlands, NJ 07732 U. S. DEPARTMENT OF COMMERCE Donald L. Evans, Secretary National Oceanic and Atmospheric Administration Vice Admiral Conrad C. Lautenbacher, Jr., USN (ret.), Administrator National Marine Fisheries Service William T. Hogarth, Assistant Administrator for Fisheries Northeast Region Northeast Fisheries Science Center Woods Hole, Massachusetts March 2003
Editorial Notes on Issues 122-152, 163, and 173-179 in the NOAA Technical Memorandum NMFS-NE Series Editorial Production For Issues 122-152, 163, and 173-179, staffofthe Northeast Fisheries Science Center's (NEFSC's) Ecosystems Processes Division have largely assumed the role of staff of the NEFSC's Editorial Office for technical and copy editing, type composition, and page layout. Other than the four covers (inside and outside, front and back) and first two preliminary pages, all preprinting editorial production has been performed by, and all credit for such production rightfully belongs to, the staff of the Ecosystems Processes Division.
Internet Availability Issues 122-152, 163, and 173-179 have been copublished, i.e., both as paper copies and as Web postings. All Web postings are available at: www.nefsc.noaa.gov/nefsc/habitat/e/h7. Also, all Web postings are in "PDF" format.
Information Updating By federal regulation, all information specific to Issues 122-152, 163, and 173-179 must be updated at least every five years.
All official updates will appear in the Web postings. Paper copies will be reissued only when and if new information associated with Issues 122-152, 163, and 173-179 is significant enough to warrant a reprinting of a given issue. All updated and/or reprinted issues will retain the original issue number, but bear a "Revised (Month Year)" label.
Species Names The NMFS Northeast Region's policy on the use of species names in all technical communications is generally to follow the American Fisheries Society's lists of scientific and common names for fishes (i.e., Robins et al. 19911), mollusks (i.e.,
Turgeon et al. 199 8 1), and decapod crustaceans (i.e., Williams et al. 19891), and to follow the Society for Marine Marmnmalogy's guidance on scientific and common names for marine mammals (i.e., Rice 19 9 8d). Exceptions to this policy occur when there are subsequent compelling revisions in the classifications of species, resulting in changes in the names of species (e.g., Cooper and Chapleau 19981; McEachran and Dunn 1998).
"Robins, C.R. (chair); Bailey, R.M.; Bond, C.E.; Brooker, J.R.; Lachner, E.A.; Lea, R.N.; Scott, W.B. 1991. Common and scientific names of fishes from the United States and Canada. 5th ed, Amer. Fish. Soc. Spec. IPubl. 20; 183 p.
'Turgeon, D.D. (chair); Quinn. J.F., Jr.; Bogan, A.E.: Coan, E.V.: Hochberg, F.G.; Lyons, W.G.: Mikkelsen, P.M.; Neves, R.J.; Roper, C.F.E.;
Rosenberg, G.: Roth, B.; Scheltema, A.; Thompson, F.G.; Vecchione, M.; Williams, J.D. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: mollusks. 2nd ed. Amer. Fish. Soc. Spec. Puhi. 26; 526 p.
'Williams, A.B. (chair); Abele, L.G.; Felder, D.L.; Hobbs, H,H., Jr.; Manning, RB.; McLaughlin, P.A.; PIrez Farfante, 1. 1989. Common and scientific names of aquatic invertebrates friom the United States and Canada: decapod crustaceans, Amer. Fish, Soc. Spec, Pu1L 17; 77 p.
"Rice. I).W. 1998. Marine mammals of the world: systematics and distribution. Soc. Mar. Mammal. Spec. PtuhI. 4; 231 p.
'Cooper. J.A.; Chapleau, F. 1998. Monophyly and interrelationships of the family Pleuronectidae (Pleuronectiformes), with a revised classification. Fish. Bull. (U.S.) 96:686-726.
rMctachran, ,.D.; l)unn, KA. 1998. Phylogenetic analysis of skates, a morphologically conservative clade of elasmobranchs (Chondrichthyes: Rajidae). Copeia 1998(2):271-290.
Page iii FOREWORD One of the greatest long-term threats to the viability of independent data sets from NMFS and several coastal commercial and recreationalfisheries is the continuing states. The species reports are also the source for the loss of marine, estuarine, and other aquatic habitats. current EFH designations by the New England and Mid-Magnuson-Stevens Fishery Conservation and Atlantic Fishery Management Councils, and Management Act (October 11, 1996) understandably have begun to be referred to as the "EFH source documents."
The long-term viability of living marine resources NMFS provided guidance to the regional fishery depends on protection of their habitat. management councils for identifying and describing EFH NMFS Strategic Plan for Fisheries of their managed species. Consistent with this guidance, Research (February 1998) the species reports present information on current and historic stock sizes, geographic range, and the period and The Magnuson-Stevens Fishery Conservation and location of major life history stages. The habitats of Management Act (MSFCMA), which was reauthorized managed species are described by the physical, chemical, and amended by the Sustainable Fisheries Act (1996), and biological components of the ecosystem where the requires the eight regional fishery management councils species occur. Information on the habitat requirements is to describe and identify essential fish habitat (EFH) in provided for each life history stage, and it includes, where their respective regions, to specify actions to conserve available, habitat and environmental variables that control and enhance that EFH, and to minimize the adverse or limit distribution, abundance, growth, reproduction, effects of fishing on EFH. Congress defined EFH as mortality, and productivity.
"those waters and substrate necessary to fish for Identifying and describing EFH are the first steps in spawning, breeding, feeding or growth to maturity." The the process of protecting, conserving, and enhancing MSFCMA requires NMFS to assist the regional fishery essential habitats of the managed species. Ultimately, management councils in the implementation of EFH in NMFS, the regional fishery management councils, fishing their respective fishery management plans. participants, Federal and state agencies, and other NMFS has taken a broad view of habitat as the area organizations will have to cooperate to achieve the habitat used by fish throughout their life cycle. Fish use habitat goals established by the MSFCMA.
for spawning, feeding, nursery, migration, and shelter, but A historical note: the EFH species reports effectively most habitats provide only a subset of these functions. recommence a series of reports published by the NMFS Fish may change habitats with changes in life history Sandy Hook (New Jersey) Laboratory (now formally stage, seasonal and geographic distributions, abundance, known as the James J. Howard Marine Sciences and interactions with other species. The type of habitat, Laboratory) from 1977 to 1982. These reports, which as well as its attributes and functions, are important for were formally labeled as Sandy Hook Laboratory sustaining the production of managed species. Technical Series Reports, but informally known as The Northeast Fisheries Science Center compiled the "Sandy Hook Bluebooks," summarized biological and available information on the distribution, abundance, and fisheries data for 18 economically important species. The habitat requirements for each of the species managed by fact that the bluebooks continue to be used two decades the New England and Mid-Atlantic Fishery Management after their publication persuaded us to make their Councils. That information is presented in this series of successors - the 38 EFH source documents - available to 38 EFH species reports (plus one consolidated methods the public through publication in the NOAA Technical report). The EFH species reports are a survey of the Memorandum NMFS-NE series.
important literature as well as original analyses of fishery-JAMES J. HOWARD MARINE SCIENCES LABORATORY JEFFREY N. CROSS, (FORMER) CHIEF HIGHLANDS, NEW JERSEY ECOSYSTEMS PROCESSES DIVISION SEPTEMBER 1999 NORTHEAST FISHERIES SCIENCE CENTER
Page iv Page v Contents Inntro du ctio n ......................................................................................................................................................................................
L ife H isto ry ......................................................................... :............................................ :.............................................................. I G eograp h ical D istrib u tio n ................................................................................................................................................................. 6 H ab itat C h ara cteristics ...................................................................................................................................................................... 8 Statu s o f th e S to c k s ......................................................................................................................................................................... I Re se a rc h N e e d s ... ...........................................................................................................................................................................
. 12 A c k n o w led g men ts ............................................................................................................................... ........................................... 12 R e fe re n c e s C ite d ............................................................................................................................................................................. 12 Tables Table I. Summary of habitat parameters for little skate, based on the pertinent literature .............................................. 15 Table 2. Summary of habitat parameters for little skate, based on the most recent NEFSC and state surveys ..................... 17 Figures Figure 1. The little skate, Leucoraja erinacea (Mitchill 1825) .............................................................................................. 19 Fig ure 2 . E gg case o f little skate .................................................................................................................................................. 20 Figure 3. Abundance (% occurrence) of the major prey items of little skate collected during NEFSC bottom trawl surveys ..... 21 Figure 4. Distribution of juvenile little skate collected during winter NEFSC bottom trawl surveys .................................... 23 Figure 5. Distribution and abundance of juvenile little skate collected during spring NEFSC bottom trawl surveys ................. 24 Figure 6. Distribution of juvenile little skate collected during summer NEFSC bottom trawl surveys .................................. 25 Figure 7. Distribution and abundance of juvenile little skate collected during fall NEFSC bottom trawl surveys ................. 26 Figure 8. Distribution and abundance of juvenile little skate in Massachusetts coastal waters .............................................. 27 Figure 9. Distribution and abundance of juvenile and adult little skate collected in Long Island Sound ................................ 29 Figure 10. Monthly log,, length frequencies of juvenile and adult little skate collected in Long Island Sound ........................ 30 Figure 11. Relative abundance catch/tow and percent occurrence for juvenile and adult little skate in Long Island Sound ......... 31 Figure 12. Seasonal distribution and abundance ofjuvenile little skate in the Hudson-Raritan estuary .................................. 32 Figure 13. Seasonal distribution and abundance of juvenile and adult little skate in Delaware Bay ........................................ 34 Figure 14. Distribution of adult little skate collected during winter NEFSC bottom trawl surveys ......................................... 38 Figure 15. Distribution and abundance of adult little skate collected during spring NEFSC bottom trawl surveys .................. 39 Figure 16. Distribution of adult little skate collected during summer NEFSC bottom trawl surveys ...................................... 40 Figure 17. Distribution and abundance of adult little skate collected during fall NEFSC bottom trawl surveys ...................... 41 Figure 18. Distribution and abundance of adult little skate in Massachusetts coastal waters ..................................................... 42 Figure 19. Seasonal distribution and abundance of adult little skate in the Hudson-Raritan estuary ....................................... 44 Figure 20. Spring/fall distributions of juveniles relative to bottom temperature, depth, and salinity based on NEFSC surveys ... 46 Figure 21. Distributions of juveniles relative to bottom temperature and depth based on Massachusetts inshore surveys ............ 48 Figure 22. Seasonal distributions of juveniles relative to temperature, depth, salinity, and DO in the Hudson-Raritan estuary ... 50 Figure 23. Seasonal distributions of juveniles and adults relative to temperature, depth, salinity, and DO in Delaware Bay ....... 54 Figure 24. Spring/fall distributions of adults relative to bottom temperature, depth, and salinity based on NEFSC surveys ........ 58 Figure 25. Distributions of adults relative to bottom temperature and depth based on Massachusetts inshore surveys ............ 60 Figure 26. Seasonal distributions of adults relative to temperature, depth, salinity, and DO in the Hudson-Raritan estuary ........ 62 Figure 27. NEFSC spring survey index of little skate biomass and commercial landings of the seven species skate complex ..... 66
Page 1 INTRODUCTION to six months to hatch. Since the water temperature of the aquarium in which the eggs were kept was slightly above The little skate [Leucoraja erinacea (Mitchill 1825); that of the natural environment, it is possible that the formerly Raja erinacea, see McEachran and Dunn incubation time was underestimated. Perkins (1965) in a (1998); Figure 1] occurs from Nova Scotia to Cape study conducted at Boothbay Harbor, Maine, found under Hatteras and is one of the dominant members of the aquarium conditions where the water temperature closely demersal fish community of the northwest Atlantic approximated that of the inshore waters, eggs deposited in (Bigelow and Schroeder 1953; Richards et al. 1963; November and December hatched after twelve months of McEachran and Musick 1975; Michalopoulos 1990). Its incubation. Johnson (1979) performed flow-through center of abundance is in the northern section of the Mid- seawater system studies using ambient temperatures Atlantic Bight and on Georges Bank, where it is found resembling those of the inshore waters of Block Island year-round over almost the entire range of temperatures Sound at 20 m. The incubation period ranged from 112-recorded for those areas (McEachran and Musick 1975). 366 d and was dependent on month of deposition. Eggs Little skate make no extensive migrations, although deposited in September 1975 hatched after an average of where it occurs inshore the species moves onshore and 360 d. Incubation time decreased progressively from offshore with seasonal temperature changes (Bigelow and September, and eggs deposited in July 1977 developed Schroeder 1953; Merriman et al. 1953; Fitz and Daiber and hatched in an average of 122 d. The rate of 1963; Richards 1963; Richards et al. 1963; Schaefer embryonic growth appeared to be directly related to 1967; Tyler 1971 a, b). It also moves north and south with temperature. In Perkins (1965) study, incubation of eggs seasonal temperature changes along the southern fringe of deposited in November and December showed the first its range (McEachran and Musick 1975). embryonic activity in March when the water temperature Smaller little skate are often confused with its had risen to 7°C.
sympatric species, winter skate (Leucoraja ocellata); the distinctions are size-dependent (McEachran and Musick 1973; McEachran 2002). Number of tooth rows, length at JUVENILES maturity, and location of pelvic denticles are the characters most commonly used to differentiate the two The young are 93-102 mm TL at hatching (Richards species (Michalopoulos 1990). et al. 1963; McEachran 2002) and are fully developed, resembling the adult in both shape and coloration.
LIFE HISTORY ADULTS EGGS Bigelow and Schroeder (1953) reported adult little The single fertilized egg is encapsulated in a leathery, skate to have an average size of 41-51 cm TL, with a greenish-brown case or capsule known as a "mermaid's maximum length of 53 cm TL. Waring (1984) calculated purse" which is deposited on the bottom and often washes the maximum size to be 53 cm TL; McEachran (2002) up on beaches. The egg cases are laid in pairs. They are reports the maximum size as 54 cm TL. Johnson rectangular in shape, 44-63 mm long and 30-45 mm wide, calculated the maximum size for little skate from Block with a hollow curved horn at each comer (Figure 2; Island Sound to be 60 cm TL for males and 62 cm TL for Vladykov .1936; Fitz and Daiber 1963). The anterior females. Maximum size and size at maturity increases horns are curved inward and are about half the length of toward the northern end of their range (Richards et al.
the case while the posterior horns are more or less straight 1963; McEachran and Martin 1977).
or slightly curved outwardly and are about as long as the case [McEachran (2002); see also Johnson (1979) for a comprehensive description of the egg case]. Walls of the AGE AND GROWTH case are smooth but have longitudinal striations. The cases have sticky filaments that allow them to adhere to Age and growth of little skate have been estimated the bottom substrates. from length frequency plots and by counting rings on External gills appear from the walls of the gill slits vertebral centra (Richards et al. 1963; Johnson 1979; 25-30 days to 90-95 days after spawning but these Waring 1984). Johnson (1979) reported mean length at disappear before hatching (Pelster and Bemis 1992). age for male little skate from Block Island Sound was Gestation is at least six months or more. Aquarium 20.0 cm TL at age 1, 30.3 cm TL at age 2, 38.7 cm TL at studies mentioned by Bigelow and Schroeder (1953) age 3, 45.1 cm TL at age 4, and 48.8 cm TL at age 5. For showed that eggs laid in May-July hatched between the females the mean length at age was 21.0 cm TL at age 1, end of. November and beginning of January, about 5-6 31.3 cm TL at age 2, 38.3 cm TL at age 3, 45.8 cm TL at months. Richards et al. (1963) also determined that eggs age 4, and 48.3 cm TL at age 5. Little skate from Georges spawned in the late spring and early summer required five Bank to Delaware Bay averaged 21.5 cm TL at age 1,
Page 2 29.3 cm TL at age 2, 36.4 cm TL at age 3, 42.0 cm TL at average total length at maturity for male and female little age 4, 46.1 cm TL at age 5, 47.2 cm TL at age 6, 47.5 cm skate in Block Island Sound was 46.3 cm TL and 45.9 cm TL at age 7, and 48.1 cm TL at age 8 (Waring 1984). TL, respectively. Johnson (1979) used females > 47 cm Bigelow and Schroeder (1953) originally reported that TL in his, laboratory studies because that was the length skate 20 cm long may be 1-1.5 yrs old, 30 cm long may that the largest percentage of females had reached be 2-3 yrs old, 40 cm long may be 3-4 yrs old, and 50 cm maturity.
long may be 6-8 yrs old. Based on the predictive equations from Frisk et al.
Richards et al. (1963), who examined skates from (2001) and the Northeast Fisheries Science Center Long Island and Block Island Sounds, determined that (NEFSC) survey maximum observed length of 62 cm TL, they grow approximately 10 cm/yr for the first three Lmat is estimated at 50 cm TL and Amat is estimated at 4 years; between the third and fourth years,. growth years (Northeast Fisheries Science Center 2000b).
decreases to around 5 cm/yr [Merriman et al. (1953) generally concurs]. Richards et, al. (1963) also noted that differences in size between the sexes were unnoticeable REPRODUCTION until skates reached adolescence. Then the males from both Sounds became longer and heavier than the females. Mating in little skate may take place at any time Adult nmales were also larger than females and the throughout the year and frequently (Bigelow and majority of those > 50 cm TL were males. Schroeder 1953; Richards et al. 1963; Johnson 1979).
Natanson (1990) performed age and growth Egg cases are also found partially to fully developed in experiments on skate from. Narragansett Bay, Rhode mature females year-round but several authors report that Island that were held in an experimental tank with a mean they are most frequently encountered from late October-temperature of 18'C and a control tank with temperatures January and from June-July (Fitz and Daiber 1963; that fluctuated with the seasons (range from 1-23'C). The Richards et al. 1963; Scott and Scott 1988); Bigelow and fish in the experimental tank were 41.0-44.7 cm TL and Schroeder (1953) also mention that eggs are taken off the fish in the control tank were 34.0-47.7 cm TL. The southern New England mostly from July to September.
growth rates of skates from the experimental tank ranged In Block Island Sound, Johnson (1979) also reported from 1.3-3.4 cm TL/yr and rates in the control tank pregnant little skate were present during all months of the ranged from 1.0-4.9 cm TL/yr. Growth of individuals year, but again the seasonal percentages of pregnant from both tanks was considered slow compared to field females varied. Periods of relatively high pregnancy-estimates for little skate by Johnson (1979), but similar to frequency were October-December and April-May, while estimates by Waring (1984). Waring's (1984) study low periods occurred in August-September and February-showed skates of this size growing from 2.30-4.65 cm March. Peaks in egg production were in November and TL/yr and Johnson's (1979) study showed faster growth May when 34% and 44% of the females examined were of 4.22-8.26 cm TL/yr. The size at age in the Natanson pregnant, respectively. The lowest levels of production (1990) study was also lower than in Johnson (1979) and came in September and March when approximately 1% of Waring's (1984) studies. The size at age from the the females were pregnant.
Natanson (1990) study supported the growth rates Johnson (1979) found the mean number of mature observed in her laboratory. Data from the Natanson and maturing eggs per fish increased significantly prior to (1990) study also indicates that growth would be slow and during the spawning peaks, reaching maxima in over the life of the individual as compared to growth rates October and May. The average number of mature and in Johnson's (1979) or Waring's (1984) studies. The maturing eggs decreased significantly between what difference is probably related to differences in vertebrae appears to -be two spawning seasons with minima in preparation and criteria for an annual band (Natanson August and January. The greatest ovarian production 1990). occurred in the spring. In Delaware Bay, Fitz and Daiber (1963) also showed that the greatest ovarian production occurred in the spring, while the size and number of eggs SIZE AT MATURITY was at a minimum in February and March.
Johnson (1979) reported that ovarian weight also Bigelow and Schroeder (1953) reported that females increased significantly during two spawning seasons.
mature when 32-43 cm TL, and males at 36-45 cmTL, Comparison of the female gonad weight expressed as a based on information supplied by others, while percentage of total body weight demonstrated two McEachran (2002) states that maturity is reached between seasonal peaks with maxima occurring in October and 35-50 cm TL. McEachran (1973) studied skates collected May; these seasonal peaks represented and increase in from Nova Scotia and the Gulf of Maine to Cape Hatteras ovarian production. After the height of spawning, the between 1967-1970 and found that about a third of the female gonad weight dropped off significantly, reaching a little skate between 42-44 cm TL as well as all those > 50 minima in January and August.
cm TL were mature; the smallest mature little skate was a Rate of egg laying in Johnson's (1979) study varied male 41 cm TL. Richards el al. (1963) reported the from 0.20-0.67 eggs/d, with an average rate. of 0.39
Page 3 eggs/d. Johnson (1979) suggests that an average female Bank were Nepthys spp., Lumbrinerisfragilis, Aphrodite little skate which spawns twice annually (once during fall hastata, maldanids, (mostly Clymenella torquata),
and spring) produces approximately 30 eggs/yr. Bigelow Glycera spp., and Pherusa affinis. A. hastata contributed and Schroeder (1953) observed that eggs in aquaria were most to the stomach volume. The polychaetes Ophelia laid at intervals of from five days to several weeks, and denticulata, Nothria conchylega, and Pectinaria sp.
were partially buried in sand. predominated in stomachs from the Gulf of Maine and the Nova Scotian shelf.
Among the minor prey items consumed included the FOOD HABITS isopods Cirolana (= Politolana?)polita and Chiridotea tuftsi. The former species accounted for almost the entire Generally, invertebrates such as decapod crustaceans volume of isopods. Most of the bivalves eaten were in the and amphipods are the most important prey items, family Solenidae, with Ensis directus the only species of followed by polychaetes (Bigelow and Schroeder 1953; this family identified. Solemya sp. was the only other Tyler 1972; McEachran 1973; McEachran et al. 1976; bivalve recognized. The most numerous fishes that were Bowman and Michaels 1984; Nelson 1993; Bowman et eaten included yellowtail flounder and longhorn sculpin.
al. 2000; Garrison 2000; Garrison and Link 2000a, b; Nelson (1993) studied the diet of little skate at two Scharf et al. 2000). isopods, bivalves, and fishes are of stations on Georges Bank, his results were similar to minor importance. Bigelow and Schroeder (1953) McEachran (1973) and McEachran et al. (1976) in terms reported hermit and other crabs, shrimps, polychaetes, of the major phyla consumed in that area. Amphipods amphipods, ascidians, bivalves, squid, fishes, and even dominated the diets numerically and decapods dominated copepods. Little skate from the Woods Hole region the diets by weight, followed by (depending on site) contained mostly crabs, followed by shrimp (Crangon polychaetes, bivalves, fish, isopods, and cnidarians.
septemspinosa), and squid. The fishes that were eaten In Sheepscot Bay, Maine, little skate ate a variety of included sand lance, alewives, herring, cunners, prey, but seemed to focus most on crustaceans (Packer silversides, tomcod, and silver hake. Hydroids are also and Langton, unpublished manuscript) and Atlantic ingested (Avent et al. 2001). herring, at least on a percent weight basis (Langton and McEachran (1973) studied skates collected from Watling 1990). C. septemspinosa, the jonah crab Cancer Nova Scotia to Cape Hatteras during 1967-1970; the borealis, the amphipods L. pinguis and U. inermis, and following diet descriptions are from him and McEachran several other varieties of crustaceans were important in et al. (1976). the diet, followed by polycheates such as Nephtys spp.
Crangon septemspinosa, Pagurus acadianus,Cancer (Packer and Langton, unpublished manuscript). In Johns irroratus,and Dichelopandalus leptocerus were the most Bay, Maine, little skate fed primarily on the decapod frequently eaten decapods in the Mid-Atlantic Bight and crustaceans C. septemspinosa and C. irroratus,followed on Georges Bank. C. septemspinosa was the most by the amphipods L. pinguis, Unciola spp. and numerous decapod in the stomachs while P. acadianus Monoculodes spp. (Hacunda 1981). Polychaetes were the and C. irroratus accounted for most of the stomach next major prey group.
volume. In the Gulf of Maine and on the Nova Scotian Smith (1950) conducted diet studies on little skate shelf Pagurus pubescens, C. septemspinosa, Hyas sp., from Block Island Sound; the diet was similar to that of and Eualus pusiolus were the most frequently eaten little skate in the McEachran (1973) and McEachran et al.
decapods. (1976) studies. L. pinguis was most abundant in the diet, The most frequently consumed amphipods in the followed by C. irroratus, C. septemspinosa, Upogebia Mid-Atlantic Bight and on Georges Bank were affinis (a mud shrimp), Glycera dibranchiata, Byblis Monoculoides sp., Unciola sp., Leptocheirus pinguis, serrata(an amphipod), Unciola irrorata,Nephtys incisa, ampeliscids, haustoriids, and Dulichia (= Dyopedos) and E. directus.
monacantha. L. pinguis predominated in the Mid-Atlantic Carlson (1991) found that decapods made up 76% of Bight and Monoculodes sp. and Unciola predominated in the diet by weight in New Haven Harbor. C.
little skate from Georges Bank. Haustoriid amphipods septemspinosa and C. irroratuswere the most important were abundant only in the little skate from Georges Bank prey items, followed by mantis shrimp, Squilla empusa.
and contributed significantly to the stomach contents only Other crustacean groups did not constitute a major during the autumn survey. Pleustes panoplus, L. pinguis, portion of the diet. Fish were the next major group, but Hippomedon serratus, Monoculodes sp., and Unciola sp. only made up 10% of the diet by weight and only 4% by were the most frequently eaten amphipods in the Gulf of number. There was a high diet overlap with other Maine and on the Nova Scotian shelf. predators including striped searobin, tautog, and Eunice pennata and Nereis spp. were the most windowpane because of their similar dependence on numerous polychaetes, with E. pennata abundant only on crustaceans.
the Nova Scotian shelf and Nereis spp. numerous only in Fitz and Daiber (1963) conducted diet studies on the Mid-Atlantic Bight. Other major polychaetes little skate in Delaware Bay. C. septemspinosa made up >
consumed in the Mid-Atlantic Bight and on Georges 70% of the diet, followed by E. directus and Euceramus
Page 4 praelongus (a burrowing crab). In the fall, the latter two were C. septemspinosa; other important decapods prey items, along with the polychaete Nereis limbata ( = included pagurid and Cancer crabs.
Neanthes succinea), were more prominent in the skates' The percentage of crustaceans in the diet of little diet than in the spring. skate 21-30 cm TL dropped to 83%, although almost half In -the inshore diet studies mentioned above, the of the diet still consisted of identifiable amphipods. The skates generally depended more on a few major prey major amphipod prey species were similar to the 11-20 species than skates from the McEachran (1973) and cm TL size class, with the addition of M edwardsi.
McEachran et al. (1976) studies. This may be attributable Identifiable decapods again made up 18-20% of the diet, to the benthic faunal composition in these inshore areas; the majority of which were again C. septemspinosa along these areas have a less diverse fauna than the wide region with Cancer and pagurid crabs. Identifiable polychaetes sampled as part of the McEachran (1973) and McEachran made up only 10-1.1% of the diet, most of which were et al. (1976) studies. But it is clear that the food habits of terebellids.
little skate are fairly generalized, and it is an opportunistic The percent occurrence of crustaceans in the diet of predator (McEachran 1973; McEachran et al. 1976; little skate 31-40 cm TL dropped further, down to 73-Nelson 1993; Packer and Langton, unpublished 78%, with identifiable amphipods making up only 32-manuscript). 36% of the overall diet. The usual amphipods were McEachran (1973) and McEachran et al. (1976) dominant; in order of abundance they were U. irrorata,L.
showed that the diet of little skate is size-dependent. pinguis, unidentifiable gammarids, B. serrata, Skate < 41 cm TL consumed considerably fewer unidentifiable ampeliscids, M edwardsi, and decapods and more amphipods than those that were > 41 unidentifiable caprellids, haustoriids, and oedicerotids.
cm TL. Most decapods eaten by skates < 30 cm TL were Identifiable decapods made up 25-28% of the diet; C.
C. septemspinosa. Haustoriid amphipods were almost septemspinosa was again the dominant decapod prey, never found in skates >ý 30 cm TL. Cumaceans and followed by Cancer and pagurid crabs, and copepods were also limited to the smaller skates. All sizes Dichelopandalus leptocerus. Identifiable polychaetes fed on fishes, ýbut the frequency of occurrence increased made up only 14-15% of the diet; the majority were with the size of the skate. Polychaetes were eaten by all terebellids and maldanids.
sizes. The percent occurrence of crustaceans in the diet The 1973-1990 NEFSC food habits database for little continued to decline for little skate 41-50 cm TL: down to skate [Figure 3; see Reid et al. (1999) for details] 66-71%, with identifiable amphipods making up only 22-generally confirms the McEachran (1973) and McEachran 28% of the diet, while identifiable decapods made up 29-et al. (1976) studies. Crustaceans dominated the diet 32%. The usual amphipods were dominant, especially L.
overall, but declined in importance with increasing skate pinguis and U. irrorata,followed by the others previously size while the percent occurrence of polychaetes mentioned. C. septemspinosa continued to be the increased with increasing skate size. Amphipods occurred dominant decapod prey, followed by Cancer and pagurid more frequently than decapods until the skates were > 41 crabs. Identifiable polychaetes made up 17-18% of the cm TL. C. septemspinosa was the major decapod prey for diet, with the dominant family being the Terebellidae.
all sizes of skate. The following is a description of the Other abundant families included the Nephtyidae, diet from the NEFSC food habits database broken down Maldanidae, Aphroditidae, and the Flabelligeridae.
by little skate size class (Figure 3). Finally, the percent occurrence of crustaceans in the For little skate 1-10 cm TL, 97% of the diet consisted diet declined to 64-69% for skate 51-60 cm TL, with of crustaceans, with 42% of the diet consisting of identifiable amphipods making up only 19-22% of the identifiable amphipods. The most abundant amphipod diet, while identifiable decapods 29-34%. L. pinguis was species included B. serrata, U. irrorata, Monoculodes the dominant amphipod; C. septemspinosa, Cancer, and intermedius, Synchelidium sp., as well as several pagurid crabs were the dominant decapods. Identifiable unidentifiable Gammaridea. Identifiable cumaceans made polychaetes made up 19-20% of the diet, with the up 27% of the diet, notable species included Cyclaspis dominant family being the Terebellidae.
varians and Diastylis spp. Identifiable decapods made up Other authors also show similar size-dependent only 8% of the diet, all of which were either C. trends in the diet of little skate. Bowman and Michaels septemspinosa or classified as unidentifiable (1984) and Bowman et al. (1987) reported that while Crangonidae. crustaceans were the dominant prey of all sizes of little For skate 11-20 cm TL, 90% of the diet consisted of skate, skate < 35 cm TL preyed mostly on amphipods crustaceans, and at least half of the diet consisted of (including Unciola) and those > 35 cm TL ate large identifiable amphipods. Major amphipod species included quantities of decapods (including C. septemspinosa).
B. serrata, U. irrorata, L. pinguis, Ericthonius Polychaetes, mollusks, and fish were found primarily in rubricornis, and several unidentifiable gammarids, little skate > 20 cm TL. Again, using NEFSC data from ampeliscids, oedicerotids, and caprellids. Identifiable 1977-1980, Bowman et al. (2000) also found that in terms decapods made up 18-20% of the diet, most of which of percent weight, crustaceans were important for all size classes of skate. Skate < 15-30 cm TL fed mostly on
Page 5 amphipods, including L. pinguis, Unciola spp, Gammarus their consumptive impact will be dependent on the levels annulatus, and Oedicerotidae. Skate 36 to > 51 cm TL fed of invertebrate biomass and/or production.
mostly on decapods, including C. irroratus, C. borealis, P. acadianus, and C. septemspinosa [although, as in the McEachran (1973) and McEachran et al. (1976) studies, PREDATORS AND SPECIES C. septemspinosa was eaten mostly by skates < 30 cm ASSOCIATIONS TL]. On Georges Bank, Nelson (1993) discovered that colonial amphipods and small, epibenthic decapods Eggs of little skate in the Gulf of Maine can be dominated the diets of little skate < 39 cm TL at both of preyed upon by sea. urchins (Strongylocentrotus his study sites, but species composition was site and size drobachiensis), and whelks (Buccinum undatum) (Cox dependent. At one site, Ericthonius fasciatus and U. and Koob 1991, 1993). Juveniles and adults are preyed inermis comprised the largest portions of the diet of upon by sharks, other skates (including winter skates),
skates < 39 cm TL. As skate length increased, E~fasciatus teleost fishes (including cod, goosefish, sea raven, declined while U. inermis became increasingly important longhorn sculpin, bluefish, summer flounder), gray seals, in the diets. For skates > 40 cm TL, the epibenthic and rock crabs (Cancer' irroratus) (McEachran et al.
decapods C. septemspinosa and young-of-the-year C. 1976; Reilly and Saila 1978; Scott and Scott 1988; irroratusand the isopod C. polita were large components Rountree 2001).
of the diet. The polychaete Glycera dibranchiata and McEachran and Musick (1975) state that little and young-of-the-year hakes (eaten mostly in summer) also winter skate co-occurred significantly in surveys from increased in the diet. At a second site, the dominant prey Nova Scotia to Cape Hatteras between 1967-1970; little items for skate < 39 cm TL was C. septemspinosa, skate was also associated with barndoor skate (Dipturus followed by (except for skates 10-19. cm TL) the laevis). Although little and winter skate are sympatric amphipod Protohaustorius wigleyi. Other notable species with similar habitat requirements,, there does not amphipods were Monoculodes edwardsi, Rhepoxynius appear to be a high degree of competitive interaction hudsoni, Pontogeneia inermis, and Aeginina longicornis; between them because they are positively correlated by C. polita and C. irroratus were the most important abundance and where the two species are most abundant epibenthic arthropods. For skates > 40 cm TL, M. (Georges Bank) they have the most similar diets and edwardsi, C. septemspinosa, C. polita, and P. inermis highest diversity of assemblages of prey species were dominant; the cnidarian Cerianthus spp. dominated (McEachran 1973; McEachran and Musick 1975; in terms of weight. McEachran et al. 1976).
In Sheepscot Bay, a study by Packer and Langton Also, even though the two species do consume the (unpublished manuscript) again indicated that the same large taxonomic groups of benthic fauna percentage of crustacean prey in the diet decreased as the (amphipods, decapods, and polychaetes), little skate feeds skate size increased. This was due to decreases in largely on epifauna, while winter skate predominately amphipods, cumaceans, and C. septemspinosa. selects infaunal organisms (McEachran 1973; McEachran Polychaetes (including Nephtys spp.) were a small but et al. 1976). McEachran (1973) and McEachran et al.
important part of the diet for skate > 20 cm TL. Atlantic (1976) show that epifaunal decapods were eaten more herring occurred only in the stomachs of fish > 40 cm TL, frequently by little skate and large burrowing polychaetes but were only prominent in terms of percent weight. and bivalves were consumed more frequently by winter Richards (1963) found that amphipods and C. skate. Little skate consumed more surface dwelling septemspinosa were more important to smaller skates. amphipods such as Unciola sp., D. monacantha, Tyler (1972) also noted that smaller skates (< 44 cm TL) ampeliscids and caprellids while winter skate ate more ate mysids and amphipods and larger skate consumed burrowing amphipods, especially haustoriids and decapods, euphausids, and polychaetes. Trichophoxus epistomus. The division of food resources Nelson (1993) calculated the predation impact of between the skates is not complete because some little skate on their Georges Bank prey. Annual estimates individuals of little skate consumed large numbers of of consumption for little skate increased as they grew infauna and some winter skate ate large numbers of
'larger. Consumption ranged from 0.085. kg/fish/year for epifauna. Both species ate considerable numbers of L.
skate 10-19 cm TL to 0.860 kg/fish/year for skate 50-59 pinguis and C. septemspinosa. Little skate occasionally cm TL. The percentage of benthic production consumed fed on haustoriids, and deep burrowing polychaetes by little skate from 1969-1990 ranged from 5-15%. (Nereis spp., Nephtys spp. and Glycera spp.) were regular Nelson (1993) suggests that in relation to the total prey items. The infaunal and epifaunal preferences of the macrofauna production on Georges Bank, little skate two skates may be more distinct in areas where they may (along with winter skate) consume < 0.02% of the total. coexist than in areas where they occur separately because These results indicate that only a small to moderate in Delaware Bay (Fitz and Daiber 1963) little skate proportion of benthic biomass vulnerable to skate. consumed relatively more infauna than it did in the areas predation is consumed by both little and winter skate, and sampled in Smith's (1950) study or the McEachran (1973) and McEachran et al. (1976) studies. Winter skate
Page 6 does not regularly occur in Delaware Bay (Fitz and assemblage found in the deep habitats on southern Daiber 1963). Georges Bank, which also included spiny dogfish, In addition, differences in the shape and size of the butterfish, 'red hake, fourspot flounder, yellowtail mouth and the number of tooth rows between the two flounder, and winter skate. The main shallow portion of species were used as evidence by McEachran and Martin Georges Bank assemblage included 31-60 cm TL little (1977) to suggest that the sympatric populations of little skate, winter skate, spiny dogfish, Atlantic cod, and winter skate underwent character displacement in windowpane, winter flounder, and sea raven. In spring, order to avoid direct competition for food resources. In the assemblage from southern New England included 31-sympatric populations, winter skate has a greater number 60 cm TL little skate, spiny dogfish, and Atlantic herring.
of tooth rows in the upper jaw and a wider and less In terms of dietary guilds or trophic groups, the two arched mouth, thus allowing them to feed more efficiently studies had slightly different viewpoints, but the diets of and deeper in the bottom than little skate. Little skate has little skate in both studies are similar to what was a relatively smaller and more arched mouth with fewer previously discussed in the Food Habits section above. In tooth rows in the upper jaw. the Garrison and Link (2000b) study, little skate fell into Using 1973-1997 NEFSC data from Nova Scotia to the "Bentho-pelagic" group, which included 10 cm to >
Cape Hatteras, as well as the same NEFSC food habits 30 cm TL little skate, winter skate, longhorn sculpin, and database discussed above, Garrison and Link (2000a) Atlantic cod. The diets of these species included shrimp investigated the dietary guild structure of the fish such as pandalids and C. septemspinosa, and benthic community. Both small (10-30 cm TL) and medium (31- invertebrates including polychaetes, gammarid 60 cm TL) sized little skate belonged to the amphipods, and bivalves. Garrison (2000) had slightly "Amphipod/shrimp eaters" group, along with winter skate different trophic groups. In autumn, 31-60 cm TL little and cusk eel; prey included .amphipods, polychaetes, skate was in the "Shrimp predators" group, which shrimp, and zooplankton. included fourspot flounder, hakes, longhorn sculpin, and The resilience of demersal fish assemblages on Atlantic cod. Prey included pandalids and C.
Georges Bank was investigated by Overholtz and Tyler septemspinosa, and benthic invertebrates including (1985) using seasonal NEFSC trawl survey data from Cancer crabs and gammarid amphipods. Small little skate 1963-1978. Of the five assemblage species groups or (10-30 cm TL) was also in the "Demersal predators" associations present on Georges Bank in spring and fall group, along with flatfish, haddocks, winter skate, and throughout the survey period, little skate belonged to the thorny skate (Amblyraja radiata). Prey included "Intermediate" and "Shallow" assemblage groups. In the gammarid amphipods, polychaetes, isopods, and Cancer Shallow assemblage the other major species present crabs, as well as C. septemspinosa. During spring, 10-60 besides little skate included Atlantic cod, winter skate, cm TL little skate was in the "Shrimp/amphipod longhorn sculpin, yellowtail flounder, and haddock; in the predators" group, along with hakes, longhorn sculpin, Intermediate assemblage, winter skate, red and silver Atlantic cod, fourspot flounder, winter skate, and thorny hake, Atlantic cod, and haddock were some of the other skate. Prey included gammarid amphipods, pandalids and major species. Overholtz and Tyler (1985) considered C. septemspinosa,polychaetes, and Cancercrabs.
little skate to be a "resident" species, since they were only On the Scotian Shelf and in the Bay of Fundy, present in two out of the five assemblages in abundance. however, Scott (1989), using research trawl survey data The Shallow assemblage covered most of Georges Bank from roughly 1970-1984 determined that little skate was in the spring and was slightly smaller in the fall. The locally abundant but did not associate closely with any Intermediate assemblage occurred mostly south of the other species.
Shallow assemblage and inside the southern edge of Georges Bank; it was somewhat larger in the fall, suggesting a migration of the species in this area to GEOGRAPHICAL DISTRIBUTION shallower water as the year progressed. The assemblages in the spring appeared to follow depth contours. In Canada, little skate occurs around Nova Scotia, Garrison (2000) and Garrison and Link (2000b) have but contrary to Bigelow and Schroeder (1953), McKenzie also investigated spatial assemblages and trophic groups (1959), Templeman (1965), and Leim and Scott (1966), is from the Georges Bank region. Using 1963-1997 NEFSC rare north of La Have Bank and probably does not occur trawl survey data from Georges Bank, as well as the same in the Gulf of St. Lawrence [McEachran 1973; NEFSC food habits database discussed above [Garrison McEachran and Musick 1975; McEachran and Martin and Link (2000b) used 1973-1997 data while Garrison 1977; Scott and Scott 1988; see also Strong and Hanke (2000) used 1991-1997 data], they found that the major (1995) ,for the 1970-1993 distribution of little skate in the predator groups were consistent across decades, with the Scotia-Fundy region]. They are considered to be very boundaries of the assemblages similar to Overholtz and abundant on both sides of the Bay of Fundy, and are the Tyler (1985). Garrison (2000) investigated the spatial most common skate inshore in the Gulf of Maine assemblages during spring and autumn. He found that (Bigelow and Schroeder 1953; McEachran and Musick during autumn, 31-60 cm TL little skate was in the 1975). Previous authors also report them to be very
Page 7 abundant along the entire coastline of the Gulf of Maine occurs in Delaware Bay when temperatures are < 15°C and Massachusetts and on Georges Bank, although (late October-May); the 1966-1999 Delaware Division of McEachran and Musick (1975) state that they are rarely Fish and Wildlife bottom trawl surveys (see below) taken in the western Gulf of Maine. Bigelow and generally confirm this (except in summer, when the few Schroeder (1953) remark that they are not found in the that were caught were found between 16-24'C). In the deeper basins and troughs of the Gulf, however, Chesapeake Bight they are most abundant during the McEachran and Musick (1975) caught them there at winter; those that remain in the Chesapeake Bight during depths > 183 m during surveys from 1967-1970. Little the summer move into deeper water (McEachran and skate are common on the southwestern part of Georges Musick 1975). Massman (1962) and Hildebrand and Bank and off Nantucket; Bigelow and Schroeder (1953) Schroeder (1928) reported little skate in lower state they are far less common on the northeastern part of Chesapeake Bay in December and in March, respectively, Georges Bank, but the NEFSC trawl surveys show little while Geer (2002) found them mostly around the Bay skate to be fairly well distributed throughout Georges mouth in high salinity waters during April and May.
Bank (see below). Little skate are considered common or abundant in Sheepscot Bay, Maine, the New Hampshire coast, Massachusetts Bay, and in New Haven Harbor JUVENILES (Nelson et al. 1983;- Collette and Hartel 1988; Carlson 1991; Packer and Langton, unpublished manuscript). McEachran and Musick (1975) seldom caught Their range extends from southern New England and smaller specimens (they do not delineate what "smaller" down the Mid-Atlantic Bight to Cape Hatteras. means) in surveys of the northwest Atlantic from 1967-Along the inshore edge of its, range, little skate 1970. They suggested the young might lie outside their moves onshore and offshore seasonally. They generally sampling region or may be less vulnerable to the gear move into shallow water during spring, and move into used; also, small specimens of little and winter skates are deeper water in winter (Bigelow and Schroeder, 1953; difficult to distinguish (McEachran and Musick 1973).
McEachran 2002). In Passamaquoddy Bay, Macdonald et Richards et al. (1963) also noted the absence of young al. (1984) determined them to be both a regular and little skate on the fishing grounds of Block Island and occasional resident, and fairly abundant, with the Long Island sounds where the larger individuals were juveniles often occurring at beach sites during summer. abundant.
Tyler (1971a) found little skate in deeper waters (37-55 NEFSC bottom trawl surveys [see Reid et al. (1999) m) of Passamaquoddy Bay from November to April with for details] captured juvenile (< 49 cm TL) little skate a few remaining until May or June, while during the year-round and show some of the seasonal remainder of the year, Tyler (1971b) found them in onshore/offshore movements mentioned above. (Note that shallower water. Hacunda (1981) considered little skate winter and summer distributions are presented as to be a summer periodic in Johns Bay, Maine, while in presence/absence data, precluding a discussion of Sheepscot Bay, Maine they were found mostly in the fall abundances.) In winter, juveniles were found from and early winter (Packer and Langton, unpublished Georges Bank to Cape Hatteras, out to the 200 m depth manuscript). Merriman et al. (1953) noted a 3-5 mile or contour (Figure 4); they were almost entirely absent from more seasonal onshore-offshore migration in Block Island the Gulf of Maine. In spring they were also found from Sound. Little skate moved inshore during spring, offshore Georges Bank to Cape Hatteras, but were also heavily in mid- to late summer, inshore in autumn, and offshore concentrated nearshore throughout the Mid-Atlantic Bight in midwinter. In Johnson's (1979) study, however, little and southern New England as well as in Cape Cod and skate did not make extensive migrations from this region; Massachusetts Bays (Figure 5). Smaller numbers were the movement of the tagged population was limited to also found along the coast of Maine and southwest Nova Long Island Sound, and seasonal onshore and offshore Scotia and near Browns Bank and the Northeast Channel.
migrations were not evident. Richards (1963) noted a Juveniles showed a more limited distribution in the change in little skate seasonal abundance at two stations summer, with small concentrations along Long Island in Long Island Sound. They were absent from a sand (Figure 6). Juveniles were more widely distributed in the bottom station during midwinter and midsummer and fall (Figure 7), and were collected from Georges Bank to were absent from a mud bottom station during the Delmarva Peninsula and, as in the spring, were again midsummer. Schaefer (1967) collected little skate in the concentrated along Long Island, southern New England, surf waters of Long Island during the spring and summer; and in Cape Cod and Massachusetts Bays. Small numbers peak abundances were in May and June. Recent surveys were again found along the coast of Maine and near of Long Island Sound [1984-1994; Gottschall et al. Browns Bank and the Northeast Channel.
(2000)] show that little skate were most abundant in Both the spring and fall 1978-2002 Massachusetts spring and fall on transitional and sand bottoms; inshore trawl surveys [see Reid et al. (1999) for details]
abundances were lowest in July, August, and September show nearly identical abundances and distributions of (see the discussion in the Habitat Characteristics section, juveniles around Nantucket and in Nantucket Sound, in below). Fitz and Daiber (1963) reported that little skate Cape Cod Bay, along the Massachusetts coast and Broad
Page 8 Sound, and north of Cape Ann, with higher collected in all areas (including west and south of concentrations west and south of Martha's Vineyard Martha's Vineyard) (Figure 18).
(Figure 8). Very few adults were caught in the Hudson-Raritan The distributions and abundances of both juveniles estuary, particularly in spring and summer (Figure 19).
and adults in Long Island Sound (Figures 9-11) as Most of that were caught in winter were in the middle of described by Gottschall et al. (2000) will be discussed in the estuary while in the fall they were a little more widely the Habitat Characteristics section. distributed throughout the estuary.
Occurrence of juveniles in the Hudson-Raritan The seasonal distribution and abundance of both estuary appears to have the same seasonal pattern that adults and juveniles in Delaware Bay were discussed Fitz and Daiber (1963) noted for little skate in Delaware previously (Figure 13).
Bay and McEachran and Musick (1975) noted for little skate in the Chesapeake Bight; i.e., they're generally absent from the estuary during the summer months. HABITAT CHARACTERISTICS Juveniles were fairly well distributed throughout the Hudson-Raritan estuary in winter and spring (Figure 12). Information on the habitat requirements and In summer the few that were left were mostly confined to preferences of little skate (based on both the pertinent the deeper and warmer waters of the Ambrose Channel literature and the most recent NEFSC and state surveys)
(see Figure 22 for temperature and depth distributions). In are presented here and summarized in Tables I and 2.
the fall, the juveniles were again fairly well distributed Little skate are generally found on sandy or gravelly throughout the Hudson-Raritan estuary (Figure 12). bottoms, but also occur on mud (Bigelow and Schroeder The 1966-1999 Delaware Bay trawl surveys (adults 1953; McEachran and Musick 1975; Langton et al. 1995; and juveniles combined; Figure 13) again confirm the Packer and Langton, unpublished manuscript). In seasonal trends noted previously for little skate. Few were southern New England, at a depth of 55 m, little skate caught in summer, while the greatest numbers were found was associated with particular microhabitat features on in the winter. The skate were more abundant in the center the surface of the sediment during the day, including of lower Delaware Bay, near the mouth (Figure 13). biogenic depressions and flat sand, but were randomly distributed at night (Auster et al. 1995). Skates are known to remain buried in depressions during the day and are ADULTS more active at night (Michalopoulos 1990). This is probably not due to diel foraging, since McEachran et al.
NEFSC bottom trawl surveys [see Reid et al. (1999) (1976) observed no diel periodicity in feeding intensity for details] captured adult little skate (> 49 cm TL) during by little skate and suggested that they may feed at any all seasons. The numbers of adults in spring and fall were time during a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period.
much lower than for juveniles of the same two seasons Bigelow and Schroeder (1953) found most little skate (winter and summer distributions are presented as < 73-91 m deep, with an overall depth range of 0-137 m presence/absence data, precluding a discussion of and down to 146 m off southern New England.
abundances), but again showed some of the, seasonal McEachran and Musick (1975) generally found them at onshore/offshore movements mentioned above. In winter, depths < Ill m, but they were occasionally taken at they were caught from Georges Bank to the North depths > 183 m, especially in the northern section of the Carolina; very few occurred in the Gulf of Maine (Figure Mid-Atlantic Bight and on Georges Bank where they 14). In spring they were also found from Georges Bank to occurred as deep as 329 m. On the Scotian Shelf, Scott North Carolina and, as with the juveniles, were also (1982) reported the depth preference of little skate to be distributed nearshore throughout the Mid-Atlantic Bight between 37-108 m. Merriman and Warfel (1948) found and along Long Island as well as in Cape Cod and little skate to be a permanent resident off southern New Massachusetts Bays (Figure 15). Small numbers were England at depths between 15-46 m, with greatest also found along the coast of Maine and southwest Nova abundances occurring in August. Edwards et al. (1962) captured little skate as deep as 384 m off New Jersey. The Scotia and near Browns Bank and the NortheastChannel.
1963-2002 NEFSC trawl surveys from the Gulf of Maine They had a limited distribution in the summer, being to Cape Hatteras (see below) indicated that during spring found mostly in southern New England, Georges' Bank, and fall most juveniles occurred at depths < 70 m, Cape Cod Bay, in the Gulf of Maine near Penobscot Bay, although a few occurred as deep as 400 m (Figure 20),
and near Browns Bank and the Northeast Channel (Figure while most adults were found < 120 m and a few were 16). Distributions in the fall were similar to those in the also as deep as 400 m (Figure 24).
spring, but few little skate were found in the Mid-Atlantic Their temperature range is generally 1-21 'C, Bight south of the Hudson Canyon (Figure 17).
although most are found between' 2-15°C (Bigelow and The distributions of adult little skate from both the Schroeder 1953; Tyler 1971a; McEachran and Musick spring and fall Massachusetts inshore trawl surveys were 1975). It was usually caught at 5-10'C on the Scotian similar to that of the juveniles, but with fewer numbers Shelf during the summers of 1970-1979 (Scott 1982).
Page 9 McEachran and Musick (1975), in surveys in the Gulf of September-October 1976 when temperatures were > 8°C, Maine and Georges Bank from 1967-1970, found little embryonic growth was obvious but slowed with skate at temperatures between 3-12'C during the winter, decreasing temperatures. Growth resumed in the early 6-14'C during the summer, and 7-14'C in the autumn. spring when the water temperature increased.
Edwards et al. (1962) captured little skate during the Johnson (1979) therefore concludes that embryonic winter from Nantucket Shoals to Cape May, New Jersey growth takes place when temperatures are > 7-8°C and at 6-12'C. The 1963-2002 spring and fall NEFSC trawl increases with increasing temperature. For those eggs that surveys from the Gulf of Maine to Cape Hatteras (see were laid when the water temperature was increasing, the below) collected juvenile little skate over a temperatures incubation time became progressively shorter as the range of 2-22°C, with most found between 4-6°C in the temperature of deposition rose. April spawned eggs spring and about 8-16'C in the fall (Figure 20). Adults hatched after an average incubation of 181 d,- whereas were also found over a temperature range of 2-21 'C, with July deposited eggs took only an average of 122 days to most found between 4-6°C in the spring and about 9- develop and hatch. Eggs spawned in the fall 15'C in the fall (Figure 24). As stated previously, Fitz overwintered, hatching the following fall. Eggs deposited and Daiber (1963) reported that little skate occurs in in the summer took about a third of the maximum time to Delaware Bay when temperatures are < 15'C (late develop, hatching out during the fall of the same year.
October-May), which generally agrees with the Delaware Thus Johnson (1979) concludes that although water Division of Fish and Wildlife bottom trawl surveys (see temperature may be lower at greater depths, it appears below). In the Hudson-Raritan estuary, they're generally that the eggs of little skate may hatch out in autumn found in waters < 16-18'C, (Figures 22 and 26). regardless of the month of deposition. However, Steves et McEachran and Musick (1975) also note that in the al. (1999) found that in the New York Bight during 1996-southern section of the Mid-Atlantic Bight little skate was 1997 little skate hatched on the continental shelf starting usually caught in the lower part of the area's temperature in mid-winter.
range, and on the Nova Scotian shelf in the upper part of the temperature range. In the southern periphery of their range they move southward during the colder months of JUVENILES the year and offshore and northward during the warmer months of the year. Steves et al. (1999) surveyed the New York Bight Scott (1982) mentions that on the Scotian Shelf during 1996-1997 and collected juvenile little skate during the summers of 1970-1979, little skate was found (mean size of 11.8 cm SL) mostly on the inner continental at preferred salinities of 31-34 ppt. In Delaware Bay, Fitz shelf at mean depths of < 40-45 m. They were also and Daiber (1963) collected little skate at salinities as low collected at a mean temperature of 8.5°C and a mean as 20 ppt, the Delaware Division of Fish and Wildlife salinity of 32 ppt.
bottom trawl surveys (see below) even collected a few as The spring and fall distributions of juvenile little low as 15 ppt. skate relative to bottom water temperature, depth, and salinity based on 1963-2002 NEFSC bottom trawl surveys from the Gulf of Maine to Cape Hatteras are EGGS shown in Figure 20. In spring, they were found in waters between 2-13 °C, with the majority at about 4-6°C. Their Bigelow and Schroeder (1953) mention studies that depth range during that season was between 1-300 m, suggest little skate deposit eggs in water not deeper than with most spread between about 11-70 m and the majority 27 m on sandy bottoms. of those between 11-30 m. They were found at salinities The rate of embryonic growth appears to be directly of between 26-36 ppt, with > 60 between 32-33 ppt.
related to temperature. In the Perkins (1965) study, During the fall, juvenile little skate were caught over a incubation of eggs deposited in November and December temperature range of about 5-22°C, with most found showed the first embryonic activity in March when the between roughly 8-16'C. They were found over a depth water temperature had risen to 7°C. Johnson (1979), as range of 1-400 m, although most were caught at depths stated previously, performed flow-through seawater between 11-70 m. They were found at salinities of system studies using ambient temperatures resembling between 30-36 ppt, with the majority at 32-33 ppt.
those of the inshore waters of Block Island Sound at 20 The spring and autumn distributions of juveniles in
- m. Johnson's (1979) laboratory study supports the Massachusetts coastal waters relative to bottom water findings of both Perkins (1965) and Richards et al. temperature and depth based on 1978-2002 (1963). Eggs deposited in the late fall and winter, when Massachusetts inshore trawl surveys are shown in Figure water temperatures in Johnson's (1979) lab were < 8°C 21.. In the spring they were found in waters ranging from did not show signs of development until temperatures 3-16'C, with the greatest percentages spread between were greater than that in the middle of April. When eggs about 8-12'C. Their depth range was from 6-65 m, with were deposited in water > 8°C, embryonic development the majority between 6-25 m. During the autumn they was evident shortly thereafter. For eggs deposited in were found in waters ranging from 5-220C, with the
Page 10 highest percentages found between about 16-18°C. Their were found between 10-11 ppm. In summer, when the depth range was from 1-65 m, with the majority found juveniles were mostly found around the Ambrose between 6-25 m. Channel (Figure 12), their temperature distribution was The distributions and abundances of both juvenile between 14-22°C, with peaks at 16' and 18'C. They and adult little skate in Long Island Sound from April to were found between 7-22 m deep, with peaks at 10 m and November 1984-1994, based on the Connecticut Fisheries at 20 m. Their salinities ranged between 23-32 ppt; most Division bottom trawl surveys, are shown in Figures 9- were between about 29-32 ppt with a slight peak at 29
- 11. The following description of their distributions ppt. They were found over a lower range of dissolved relative to depth and bottom type is taken verbatim from oxygen levels of between 5-9 ppm;"most were found Gottschall et al. (2000). between 6-8 ppm. In the fall they were found between 5-Little skate taken in the survey ranged from 8-51 cm 17'C, with most concentrated around 7-13'C. Their (Figure 10). When abundance was high during the spring depth range during the fall was between 4-21 m, with the period (Figure I IA), little skate were most abundant on majority at 5-8 m. Their salinities ranged between 17-33 transitional and sand bottom (Figure 1iB) in the Eastern ppt, with peaks between 27-29 ppt. They were found over Basin and along the Mattituck Sill between Guilford, a range of dissolved oxygen levels of between about 6-12 Connecticut and Mattituck, New York (Figure 9). ppm, with peaks at 8-9 ppm.
Abundance decreased west of the Mattituck Sill where The seasonal distributions of both juveniles and mud bottom is more common. However, little skate were adults in Delaware Bay relative to. bottom water abundant in some areas in the Central Basin where temperature, depth, salinity, and dissolved oxygen based transitional and sand bottom exists, such as an area south on 1966-1999 Delaware Division of Fish and Wildlife of New Haven, and along the Long Island shore near bottom trawl surveys are shown in Figure 23. During the Shoreham, New York. In April, little skate abundance winter they were found between 3-12'C, with the was highest in depths < 9 m and low in depths > 27 m majority between 7-8°C. Their depth range during winter (Figure I IC). During June the reverse occurred - was between 7-18 m, with bimodal peaks between abundance was highest in depths > 27 m and low in approximately 8-10 m and 14-15 m. Their salinities depths < 9 m. During the summer, a period of low ranged between about 18-30 ppt and 34-35 ppt, most abundance, little skate still occurred in the same areas as were found between 25-30 ppt. They were found over a in the spring, but the largest catches occurred in the range of dissolved oxygen levels of between 9-12 ppm; Eastern Basin. Abundance increased during the fall most were found between 9-10 ppm. In spring, they were months and. November. When abundance peaked in found over a wider temperature range of between 4-17'C, November, skate were again concentrated on transitional with peaks scattered throughout the range (e.g., 7°C and bottom in depths between 9-27 m near Mattituck, and in 13'C). Their depth range was between about 4-21 m, depths < 18 m near Guilford. In contrast with spring, again with peaks scattered throughout (e.g., 8 m and 13 large catches were not recorded over the large sand lobe m). Their salinities ranged between 21-33 ppt, with a few that extends from the Eastern Basin onto the Mattituck at 15 ppt and 19 ppt. There was a peak, in terms of catch, Sill (Gottschall et al. 2000). of close to 30% at 30 ppt. They were found over a range The seasonal distributions of juveniles in the of dissolved oxygen levels of between 6-14 ppm, most Hudson-Raritan estuary relative to -bottom water were found between 9-10 ppm. In summer, the juveniles temperature, depth, salinity, and dissolved oxygen based and adults were found over a temperature range of about on 1992-1997 Hudson-Raritan trawl surveys are shown in 16-24°C, with a peak at 22°C. They were found at depths Figure 22. The surveys show that during the winter of between 13-18 m, with a few at 9 m; most were at 13 juveniles were found mostly between 0-7°C, with the m and 15 m. Their salinities ranged between 24-32 ppt, majority at 4-5°C. Their depth range during that season with a peak at 31 ppt. They were found over a lower and was between 4-24 m, with most caught between 5-8 m. narrower range of dissolved oxygen levels than in spring:
Their salinities ranged between about 20-35 ppt, most 5-8 ppm. During the fall they were found between 8-were found roughly between 25-26 ppt and between 30- 21 'C, with a peak at 10°C. Their depth range during that 32 ppt. They were found over a range of dissolved season was between 7-19 m, with a few at 24 m; most oxygen levels of between 9-14 ppm; most were found were between 7-9 m and 13-14 m. Their salinities ranged between 10-12 ppm with a peak at 12 ppm. In spring, between about 20-32 ppt, with a few at 16 ppt and a peak little skate were found over a wider temperature range of at 28 ppt. They were found over a range of dissolved between 2-18'C, with bimodal peaks between oxygen levels of between 6-10 ppm, the majority were approximately 6-90 C and 15-17'C. The bimodality may between 8-9 ppm.
be a function of the greater number of trawls done within those temperature intervals. Their depth range was between 4-22 m, with most found between 6-8 m. Their ADULTS salinities ranged between 15-33 ppt, the majority were found between 25-28 ppt. They were found over a range The spring and fall distributions of adult little skate of dissolved oxygen levels of between 6-13 ppm; most relative to bottom water temperature, depth, and salinity
Page 11 based on 1963-2002 NEFSC bottom trawl surveys from ppt, with -a peak between 28-29 ppt. They were found the Gulf of Maine to Cape Hatteras are shown in Figure over a range of dissolved oxygen levels of between 7-12
- 24. In spring, adult little skate were caught at ppm, with most found at 8 ppm.
temperatures between 2-13'C, with most between 4-6°C The seasonal distributions of both juveniles and and close to 40% of the total caught in 5 C waters. adults in Delaware Bay relative to bottom water During that period they were found at a depth range of I - temperature, depth, saliniity, and dissolved oxygen based 300 m, with the majority spread between II m to about on Delaware Division of Fish and Wildlife bottom trawl 101-120 m. They were found at a salinity range of surveys were discussed previously (Figure 23).
between 29-35 ppt, with the majority found at 33 ppt.
During the fall, they were found over a temperature range of 5-21 'C, with most caught between about 9-14'C. STATUS OF THE STOCKS They were found over a depth range of 1-400 m, with most caught at depths between about 41-80 m. They were The following section is based on Northeast Fisheries found at a salinity range of between 31-36 ppt, with the Science Center (2000a, b). "'
majority found at 32-33 ppt. The principal commercial fishing method used to The spring and autumn distributions of adults in catch all seven species of skates [little, barndoor, winter, Massachusetts coastal waters relative to bottom water thorny, clearnose (Raja eglanteria), rosette (Leucoraja temperature and depth are shown in Figure 25. In the garmani), smooth (Malacorajasenta)] is otter trawling.
spring they were found in waters ranging from 3-16'C; Skates are frequently taken as bycatch during groundfish the majority were found between approximately 5-12'C. trawling and scallop dredge operations and discarded During that same season the adults were found from recreational and foreign landings are currently about 6-75 m, with most found between 6-30 m. In insignificant, at < 1% of the total fishery landings.
autumn they were found between 5-21°C. The Skates have been reported in New England fishery distribution was somewhat bimodal, with peaks at 10°C landings since the late 1800s. However, commercial and 16'C. The depth range of the adults during autumn fishery landings, primarily from off Rhode Island, never was between about 1-65 m, with most found between 6- exceeded several hundred metric tons until the advent of 25 m. distant-water fleets during the 1960s. Landings are not The distributions and abundances of both juvenile reported by species, with over 99% of the landings and adult little skate in Long Island Sound relative to reported as "unclassified skates." Skate landings reached depth and bottom type were discussed previously (Figures 9,500 mt in 1969, but declined quickly during the 1970s, 9-11; Gottschall et al. [2000]). falling to 800 mt in 1981 (Figure 27). Landings have Few adults were caught during the 1992-1997 since increased substantially, partially in response to Hudson-Raritan estuary trawl surveys, their seasonal increased demand for lobster bait, and more significantly, distributions relative to bottom water temperature, depth, to the increased export market for skate wings. Wings are salinity, and dissolved oxygen are shown in Figure 26. taken from winter and thorny skates, the two species During the winter they were found in a narrow range of currently used for human consumption. Bait landings are temperatures: 1-5°C with the majority at 3-4°C. They presumed to be primarily from little skate, based on areas were found in a depth range of about 5-16 m, with most at fished and known species distribution patterns. Landings 7 m. Their salinities ranged between 20-34 ppt, most were for all skates increased to 12,900 mt in 1993 and then found roughly between 25-27 ppt, between 29-30 ppt, declined somewhat to 7,200 mt in 1995. Landings have and at 34 ppt. They were found over a range of dissolved increased again since 1995, and the 1998 reported oxygen levels of between 10-13 ppm, with most found commercial landings of 17,000 mt were the highest on between 10-12 ppm. In spring, they were found over a record (Figure 27). In terms of total recreational landings wider range of temperatures from about 7-11 'C and for little skate, they varied between < 1000 and 56,000 between 14-16'C, with a peak at 9VC* They were caught- fish, equivalent to < I to 15 mt, during 1981-1998.
at depths between 7-8 m and between 14-15 m with the The biomass for the seven skate species is at a majority at 8 m. Their salinities ranged between 25-26 ppt medium level of abundance. For the aggregate complex, and 28-29 ppt, with peaks at 25 ppt and 29 ppt. They the NEFSC spring survey index of biomass was relatively were found over a range of dissolved oxygen levels of constant from 1968-1980, then increased significantly to between 8-9 ppm and 11-12 ppm, with most found peak levels in the mid- to late 1980s. The index of skate between 11-12 ppm. Only two adult little skate were complex biomass then declined steadily until 1994, but caught in the summer, at 17-18'C and at a depth of 7 m has recently increased again. The large increase in skate and 10 m. They were found at salinities of 28-29 ppt, and biomass in the mid- to late 1980s was dominated by little at dissolved oxygen levels of 6 ppm and 9 ppm. During and winter skate. The recent increase in aggregate skate the fall they were spread over a temperature range of 5- biomass has been due to an increase in small sized skates 17'C, with a peak at 12'C. Their depth range was (< 100 cm max. length: little, clearnose, rosette, and between 5-16 m, most were caught at 6 m and 9 m. Their smooth) - primarily little skate, which, in 1999, was at its salinities during that time period ranged between 18-32 highest abundance (Figure 27). Little skate is not
Page 12 considered to be overfished (Northeast Fisheries Science continental shelf and slope. Mar. Ecol. Prog. Ser. 127:
Center 2000a, b). 77-85.
Avent, S.R., S.M. Bollens, M. Butler, E. Horgan, and R.
Rountree. 2001. Planktonic hydroids on Georges RESEARCH NEEDS Bank: ingestion and selection by predatory fishes.
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Imprecise reporting of fishery statistics where several Bigelow, H.B. and W.C. Schroeder. 1953. Fishes of the skate species are lumped together under one category Gulf of Maine. U.S. Fish Wildl. Serv., Fish. Bull. 53.
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basic changes in community structure and profound Bowman, R.E., T.R. Azarowitz, E.S. Howard, and B.P.
reduction in populations of larger, slower growing species Hayden. 1987. Food and distribution of juveniles of (Dulvy et al. 2000; Musick et al. 2000). Thus, it is seventeen northwest Atlantic fish species, 1973-important to have fishery-independent data on skates 1976. NOAA Tech. Mem. NMFS-F/NEC-45.57 p.
where the individual species are reported; it is also Bowman, R.E. and W.L. Michaels. 1984. Food of necessary to work out any identification problems seventeen species of northwest Atlantic fish. NOAA between little and winter skate. Tech. Mem. NMFS-F/NEC-28. 183 p.
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suggests the following research needs: Grosslein. 2000. Food of northwest Atlantic fishes.
- More life history studies (including studies on age, and two species of squid. NOAA Tech. Mem. NMFS-growth, maturity, and fecundity) are necessary. NE-155. 138 p.
- Studies of stock structure are needed to identify unit Carlson, J.K. 1991. Trophic relationships among stocks. demersal fishes off New Haven Harbor (New Haven,
" Explore possible stock-recruit relationships by CT) with special emphasis on the winter flounder examination of NEFSC survey data. (Pseudopleuronectes americanus). M.S. thesis,
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Dulvy, N.K., J.D. Metcalfe, J. Glanville, M.G. Pawson,
- Investigate historical NEFSC survey data from the R/V Albatross III during 1948-1962 when -they and J.D. Reynolds. 2000. Fishery stability, local extinctions, and shifts in community structure in become available, as they may provide valuable historical context for long-term trends in skate skates. Conserv. Biol. 14: 283-293.
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ACKNOWLEDGMENTS Rep. Fish. 397.31 p.
Fitz, E.S., Jr. and F.C. Daiber. 1963. An introduction to The authors thank Barry Shafer, John McCarthy, the biology of Raja eglanteria Bosc 1802 and Raja Tom Finneran, Annette Kalbach, and Meredith Lock for erinacea Mitchill 1825 as they occur in Delaware producing the maps and graphics. Thanks also to Claire Bay. Bull. Bingham Oceanogr. Collect., Yale Univ.
Steimle and Judy Berrien for literature reviews and 18 (3): 69-97.
interlibrary loans. Frank Almeida and Kathy Sosebee of Frisk, M.G., T.J. Miller, and M.J. Fogarty. 2001.
the NEFSC Woods Hole provided much needed Estimation and analysis of biological parameters in information, input, and reviews.
elasmobranch fishes: a comparative life history study.
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Studies on the marine resources of southern New England. IX. The biology of the little skate Raja erinacea Mitchill. Bull. Bingham Oceanogr. Collect.,
Yale Univ. 18 (3): 5-68.
Rountree, R.A. 2001 Dec. 28. Diets of NW Atlantic fishes and squid. <http://www.fishecology.org/diets/
summary.htm>. Accessed 2002 July 18.
Schaefer,- R.H. 1967. Species composition, size and seasonal abundance of fish in the surf waters of Long Island. N.Y. Fish Game J. 14: 1-46.
Scharf, F.S., F. Juanes, R.A. Rountree. 2000. Predator size-prey size relationships of marine fish predators:
interspecific variation and effects of ontogeny and body size on trophic-niche breadth. Mar. Ecol. Prog.
Ser, 208: 229-248.
Scott, J.S. 1982. Depth, temperature and salinity preferences of common fishes of the Scotian Shelf. J.
Northwest Atd. Fish. Sci. 3: 29-39.
Scott, J.S. 1989. Matrix analysis of co-occurrences of fishes of the Scotian Shelf and Bay of Fundy. Can. J.
Fish. Aquat. Sci. 46: 191-197.
Scott, W.B. and M.G. Scott. 1988. Atlantic fishes of Canada. Can. Bull. Fish. Aquat. Sci. 219. 731 p.
Smith, F.E. 1950. The benthos of Block Island Sound.
The invertebrates, and their quantities and their relations to the fishes. Ph.D. dissertation, Yale Univ.,
New Haven, CT. 213 p.
Page 15 Table 1. Summary of habitat parameters for little skate, based on the pertinent literature.
Life Stage Depth Substrate Salinity Temperature Egg capsule is deposited on the Egg capsule is Rate of embryonic growth directly related to Eggs bottom, perhaps in water < 27 deposited on the temperature. Incubation of eggs deposited in m deep. bottom. In aquaria, November/December show first embryonic eggs were partially activity in March when water temperature rises buried in sand. to 7°C. Embryonic growth takes place when temperatures are > 7-8°C and increases with increasing temperature.
Along the inshore edge of its Sandy or gravelly In Delaware Overall temperature range is 1-21 'C, although Juveniles 2 range, little skate moves bottoms, but also on Bay, little skate most are found between 2-15'C. Gulf of Maine onshore and offshore mud. Southern New were collected and Georges Bank (1967-1970): caught at seasonally. Generally move into England at 55 m: at salinities as temperatures between 3-12'C during winter, 6-shallow water during spring, little skate low as 15-20 14'C during summer, 7-14'C in autumn.
deeper water in winter. May associated with ppt. Juveniles Nantucket Shoals to Cape May, New Jersey leave some estuaries for deeper particular (mean size 11.8 during winter: 6-12'C. Juveniles (mean size 11.8 water during warmer months. microhabitat cm SL) cm SL) collected in the New York Bight (1996-features on surface collected in the 1997) at a mean temperature of 8.5°C. Occurs in Generally caught at depths < of sediment during New York Delaware Bay when temperatures are < 15'C Ill m, but occasionally at the day, including Bight (1996- (late October-May). In southern section of Mid-depths > 183 m, especially in biogenic depressions 1997) at a mean Atlantic Bight usually caught in the lower part of northern section of the Mid- and flat sand, but salinity of 32 the area's temperature range, and on the Nova Atlantic Bight and on Georges randomly distributed ppt. Scotian shelf in the upper part of temperature Bank where they can be as deep at night. Skates are range.
as 329 m; caught as deep as 384 known to remain m off New Jersey. Juveniles buried in Inshore they move onshore/offshore with (mean size 11.8 cm SL) depressions during seasonal temperature changes; also moves north collected in the New York the day and are and south with seasonal temperature changes Bight (1996-1997) at mean more active at night. along southern fringe of their range. May leave depths of< 40-45 m. In Long Island some estuaries for deeper water during warmer Sound (1984-1994) months.
In Long Island Sound (1984- in spring and fall, 1994) during spring, abundance most abundant on highest in depths < 9 m, low in transitional and sand depths > 27 m. During summer, bottoms.
abundance highest in depths >
27 m, low in depths < 9 m.
During fall, most between 9-27 m near Mattituck, and in depths
< 18 m near Guilford.
Same as for juveniles. Same as for Same as for Same as'for juveniles.
Adults' juveniles, juveniles.
Bigelow and Schroeder (1953); Perkins (1965); Johnson (1979).
2 Bigelow and Schroeder (1953); Merriman et al. (1953); Edwards el al. (1962); Fitz and Daiber (1963); Richards (1963); Richards et al. (1963); Schaefer (1967); Tyler 1971(a, b); Langton et al. (1995); McEachran and Musick (1975); Hacunda (1981); Michalopoulos (1990); Auster el al. (1995); Steves et al. (1999); Gottschall et al. (2000); McEachran (2002); Packer and Langton (unpublished manuscript); Delaware Division of Fish and Wildlife bottom trawl surveys (1966-1999).
3 Bigelow and Schroeder (1953); Merriman et al. (1953); Edwards el al. (1962); Fitz and Daiber (1963); Richards (1963); Richards el al. (1963); Schaefer (1967); Tyler 1971(a, b); Langton et al. (1995); McEachran and Musick (1975); Hacunda (1981); Michalopoulos (1990); Auster et al. (1995); Gottschall et al. (2000); McEachran (2002); Packer and Langton (unpublished manuscript); Delaware Division of Fish and Wildlife bottom trawl surveys (1966-1999).
Page 16 Table I. cont'd.
Life Stage Prey Predators/Species Associations N/A Eggs of little skate in the Gulf of Maine can be preyed upon by sea urchins Eggs' (Strongylocentrotus drobachiensis)and whelks (Buccinum undatum).
Food habits fairly generalized; Predators: sharks, other skates (including winter skates), teleost fishes Juveniles 2 little skate an opportunistic (including cod, goosefish, sea raven, longhorn sculpin, bluefish, summer predator although inshore skates flounder); gray seals, and rock crabs (Cancer irroratus).
generally depend more on a few major prey species. Decapod Little and winter skate co-occur from Nova Scotia to Cape Hatteras; little crustaceans and amphipods are skate also associated with barndoor skate. Although little and winter skate the most important prey items, are sympatric species with similar habitat requirements, there's not a high followed by polychaetes. degree of competitive interaction between them because they are positively Isopods, bivalves, hydroids, and correlated by abundance. Also, little skate feeds largely on epifauna, while fishes are of minor importance. winter skate predominately selects infauna. Sympatric populations of little Decapod prey include: Crangon and winter skate also undergo character displacement in order to avoid septemspinosa, Pagurusspp., direct competition for food resources. Using 1973-1997 NEFSC data from Cancerspp. Amphipods: Nova Scotia to Cape Hatteras and NEFSC food habits database, both small Monoculoides spp., Unciola (10-30 cm TL) and medium (31-60 cm TL) sized little skate belonged to spp., Leptocheirus pinguis, the "Amphipod/shrimp eaters" group, along with winter skate and cusk eel; Byblis serrata,ampeliscids, prey included amphipods, polychaetes, shrimp, and zooplankton.
haustoriids. Polychaetes: Eunice pennata, Nereis spp., Nepthys On Georges Bank, little skate belongs to assemblages that include Atlantic spp., Lumbrinerisfragilis, cod, winter skate, longhorn sculpin, yellowtail flounder, red and silver Aphrodite hastata, maldanids, hake, haddock, spiny dogfish, fourspot flounder, butterfish, windowpane, Ophelia denticulata,terebellids. winter flounder, sea raven, Atlantic herring. Also on Georges Bank, little Fish: sand lance, yellowtail skate falls into various dietary guilds or trophic groups, depending on the flounder, longhorn sculpin, study. Garrison and Link (2000b): "Bentho-pelagic" group included 10 cm Atlantic herring. Generally, to > 30 cm TL little skate, winter skate, longhorn sculpin, Atlantic cod.
skates - < 30-40 cm TL Diets of these species included shrimp such as pandalids and C.
consumed more amphipods than septemspinosa, and benthic invertebrates including polychaetes, gammarid larger skates; skates - > 30-40 amphipods, bivalves. Garrison (2000): In autumn, "Shrimp predators" cm TL consumed more group included 31-60 cm TL little skate, fourspot flounder, hakes, longhorn decapods, as well as polychaetes sculpin, Atlantic cod. Prey included pandalids and C. septemspinosa, and and fish. Depending on the benthic invertebrates including Cancercrabs and gammarid amphipods.
study, C. septemspinosa was a "Demersal predators'" group included 10-30 cm TL little skate, flatfish, prominent component of the diet haddocks, winter skate, thorny skate. Prey included gammarid amphipods, of either large or small skates, or polychaetes, isopods, Cancercrabs, C. septemspinosa. During spring, both. "Shrimp/amphipod predators" group included 10-60 cm TL little skate, hakes, longhorn sculpin, Atlantic cod, fourspot flounder, winter skate, thorny skate. Prey included gammarid amphipods, pandalids, C.
seotemsDinosa. tolvchaetes. Cancercrabs.
Same as for juveniles; however, Same as for juveniles, but note differences between larger and smaller Adults 3 note that larger skates consume skates.
more decapods as well as polychaetes and fish rather than amphipods.
I Cox andKoob (1991, 1993).
2 Smith (1950); Bigelow and Schroeder (1953); Fitz and Daiber (1963); Richards (1963); Tyler (1972); McEachran (1973);
McEachran and Musick (1975); McEachran et al. (1976); McEaclhran and Martin (1977); Reilly and Saila (1978); Hacunda (1981);
Bowman and Michaels (1984); Overholtz and Tyler (1985); Bowman er al. (1987); Scott and Scott (1988); Langton and Watling (1990); Carlson (1991); Nelson (1993); Bowman et al. (2000); Garrison (2000); Garrison and Link (2000a, b); Scharf et al. (2000);
Avent et al. (2001); Rountree (2001); Packer and Langton (unpublished manuscript); NEFSC 1973-1990 food habits database.
3 Smith (1950); Bigelow and Schroeder (1953); Fitz and Daiber (1963); Richards (1963); Tyler (1972); McEachran (1973);
McEachran and Musick (1975); McEachran et al. (1976); McEachran and Martin (1977); Reilly and Saila (1978); Hacunda (1981);
Bowman and Michaels (1984); Overholtz and Tyler (1985); Bowman et al. (1987); Scott and Scott (1988); Langton and Watling (1990); Carlson (1991); Nelson (1993); Bowman et al. (2000); Garrison (2000); Garrison and Link (2000a, b); Scharf et al. (2000);
Avent et al. (2001); Rountree (2001); Packer and Langton (unpublished manuscript); NEFSC 1973-1990 food habits database.
Page 17 Table 2. Summary of habitat parameters for little skate, based on the most recent NEFSC and state surveys mentioned in the text.
Life StageI Survey Depth I Temperature Salinity/DO 1963-2002 spring Spring: range of 1-300 m, most Spring: range of 2-13'C, with Spring: range of 26-36 ppt, >
Juveniles and fall NEFSC spread between about 11-70 m majority at about 4-6°C. 60 between 32-33 ppt.
trawl surveys from and majority of those between Fall: range of about 5-22°C, Fall: range of 30-36 ppt, Gulf of Maine to 11-30 m. most between roughly 8-16°C. majority at 32-33 ppt.
Cape Hatteras. Fall: range of 1-400 m, most between 11-70 m.
1978-2002 Spring: range of 6-65 m, Spring: range of 3-16'C,'
Massachusetts majority between 6-25 m. greatest percentages spread inshore trawl Fall: range of 1-65 m, majority between about 8-12'C.
surveys. between 6-25 m. Fall: range of 5-22°C, highest percentages between about 16-18°C.
1992-1997 NEFSC Winter: range of 4-24 m, most Winter: range of 0-7°C, most Winter: range of 20-35 ppt, trawl surveys of the between 5-8 m. between 4-5°C. most between 25-26 ppt and Hudson-Raritan Spring: range of 4-22 m, most Spring: range of 2-18'C, with 30-32 ppt / range of 9-14 ppm, estuary. between 6-8 m. bimodal peaks between 6-9°C most between 10-12 ppm, peak Summer: range of 7-22 m, and 15-17.°C. at 12 ppm.
peaks at 10 m and at 20 m. Summer: range of 14-22°C, Spring: range of 15-33 ppt, Fall: range of 4-21 m, most with peaks at 160 and 18'C. most between 25-28 ppt / range between 5-8 m. Fall: range of 5-17'C, most of 6-13 ppm, most between 10-concentrated around 7-13'C. 11 ppm.
Summer: range of 23-32 ppt, most between about 29-32 ppt, slight peak at 29 ppt / range of 5-9 ppm, most between 6-8 ppm.
Fall: range of 17-33 ppt, peaks between 27-29 ppt / range of about 6-12 ppm, peaks at 8-9 ppm.
1966-1999 Winter: range of 7-18 m, Winter: range of 3-12'C, Winter: range of 18-30 ppt and Delaware Division bimodal peaks between majority between 7-8 °C. 34-35 ppt, most between 25-30 of Fish and Wildlife approximately 8-10 m and 14- Spring: range of 4-17'C, peaks ppt / range of 9-12 ppm, most bottom trawl 15 m. scattered throughout (e.g., 7°C between 9-10 ppm.
surveys of Spring: range of about 4-21 m, and 13'C). Spring: range of 21-33 ppt, a Delaware Bay peaks scattered throughout Summer: range of about 16- few at 15 ppt and 19 ppt; a (juveniles and (e.g., 8 m and 13 m). 24°C, peak at 22°C. peak, in terms of catch, of close adults combined) Summer: range of 13-18 m, a Fall: range of 8-21 'C, peak at to 30% at 30 ppt / range of 6-14 few at 9 m; most at 13 m and lo1C. ppm, most between 9-10 ppm.
15 m. Summer: range of 24-32 ppt, Fall: range of 7-19 m, a few at peak at 31 ppt / range of 5-8 24 m; most between 7-9 m and ppm.
13-14 m. Fall: range of about 20-32 ppt, a few at 16 ppt, peak at 28 ppt/
range of about 6-10 ppm, majority between 8-9 ppm.
Page 18 Table 2. cont'd.
Life Stage Survey Depth Temperature Salinity/DO 1963-2002 spring Spring: range of 1-300 m, Spring: range of 2-13'C, most Spring: range of 29-35 ppt, Adults and fall NEFSC majority spread between I I m between 4-6°C and close to majority at 33 ppt.
trawl surveys from to about 101-120 m. 40% of the total caught in 5°C Fall: range of 31-36 ppt, Gulf of Maine to Fall: range of 1-400 m, most waters. majority at 32-33 ppt.
Cape Hatteras. between about 41-80 m. Fall: range of 5-21 'C, most between about 9-14'C.
1978-2002 Spring: range of about 6-75 m, Spring: range of 3-16'C, Massachusetts most between 6-30 m. majority between inshore trawl Fall: range of about 1-65 m, approximately 5-12'C.
surveys. most between 6-25 m. Fall: range of 5-21 'C, distribution somewhat bimodal, with peaks at 10C and 16'C.
1992-1997 NEFSC Winter: range of about 5-16 m, Winter: range of 1-5°C, Winter: range of 20-34 ppt, trawl surveys of the most at 7 m. majority at 3-4°C. most between 25-27 ppt, Hudson-Raritan Spring: range of 7-8 m and 14- Spring: range of about 7-1 °"C between 29-30 ppt, and at 34 estuary. 15 m, majority at 8 mi. and 14-16'C, peak at 9°C. ppt / range of 10-13 ppm, most Summer: only two adults found Summer: only two adults found between 10-12 ppm.
at 7 m and 10 m. at 17-18'C. Spring: range of 25-26 ppt and Fall: range of 5-16 m, most at 6 Fall: range of 5-17'C, peak at 28-29 ppt, peaks at 25 ppt and m and 9 m. 12'C. 29 ppt / range of 8-9 ppm and 11-12 ppm, most between 11-12 ppm.
Summer: only two adults caught at 28-29 ppt / 6 ppm and 9 ppm.
Fall: range of 18-32 ppt, peak between 28-29 ppt / range of 7-112 ppm, most at 8 ppm.
1966-1999 See juveniles. See juveniles. See juveniles.
Delaware Division of Fish and Wildlife bottom trawl surveys of Delaware Bay (juveniles and adults combined).
Page 19 Figure 1. The little skate, Leucoraja erinacea(Mitchill 1825). Top: male, from Murdy et al. (1997). Bottom: female, from Scott and Scott (1988).
Page 20 Capsule
<- Length >
Horn Canal Horn Figure 2. Egg case of little skate, from Johnson (1979).
Page 21 1973-1980 1981-1990 Decapoda 8%
Cumacea 27 -Isopoda 4%
Unide ntified Crust*acea 15%
Oth er prey phyla 2%
lychaeta 1%
Amphipoda 42%
1-10 cm, n = 46 Unidentified
\Crustacea 11%
Other prey phyla 3% 2%
Other Crustacea 1%
KPolychaeta 7%
Decapoda 20%
11-20 cm, n = 137 11-20 cm, n = 84 Amphipoda 45%
Unidentified Other prey phyla 2%
Cumacea 5% Crustacea 6%
Isopoda 4% Other prey phyla 6%
poda 18% Polychaeta 11% Isopoda 3%'
Other Crustacea 5% Decapoda 20 Oth 21-30 cm, n = 109 21-30 cm, n = 343 Figure 3. Abundance (% occurrence) of the major prey items of little skate collected during NEFSC bottom trawl surveys from 1973-1980 and 1981-1990. Methods for sampling, processing, and analysis of samples differed between the time periods [see Reid et al. (1999) for details].
Page 22 1973-1980 1981-1990 Other prey phyla 1% mphipoda 32%
Crustacea shrimp 5%
Unidentified Unidentified Crustacea 6 Crustacea 1%
Other prey phyla 3% Fish 6%
Fish 3%
Mnlhicrn* 9%/ Decapoda 28%, Mollusca 6%
Other Crustacea 2%
Decapoda "I-Polychaeta 25° D"Other Crustacea 1%15% Polychaeta 14%
Isopoda 50 31-40 cm, n = 215 31-40 cm, n = 784 Unidentified Crustacea 6%
Other prey phyla 6%
41-50 cm, n = 772 41-50 cm, n = 2227 Decapoda Unidentified Crustacea 6%
Other prey phyla 8%
Other Crustacea 2% 1--, *
- Yo Polychaeta 19%
51-60cm, n = 50 51-60 cm, n = 185 Figure 3. cont'd.
Page 23 Figure 4. Distribution of juvenile little skate collected during winter NEFSC bottom trawl surveys [1964-2002, all years combined; see Reid et al. (1999) for details]. Survey stations where juveniles were not found are not shown.
Page 24 Figure 5. Distribution and abundance of juvenile little skate collected during spring NEFSC bottom trawl surveys [1968-2002, all years combined; see Reid et al. (1999) for details].
Page 25 Figure 6. Distribution of juvenile little skate collected during summer NEFSC bottom trawl surveys [1963-1995, all years combined; see Reid et al. (1999) for details]. Survey stations where juveniles were not found are not shown.
Page 26 Fall/juveniles
(<= 49 cm)
Number per tow 1-10 0 11 -100 0 101 - 1000 0 > 1000 Little Skate NEFSC Bottom Trawl Surveys (1963 - 2001)
Figure 7. Distribution and abundance ofjuvenile little skate collected during fall NEFSC bottom trawl surveys [1963-2001, all years combined; see Reid et al. (1999) for details].
Page 27 Little Skate Massachusetts Inshore Trawl Survey (1978 - 2002)
Spring/juveniles F"
(<= 49 cm)
Number per tow
- 1-10
- 11-100
- 101 -500
> 500 Massachusetts d
.e-Figure 8. Distribution and abundance ofjuvenile little skate in Massachusetts coastal waters collected during the spring and autumn Massachusetts inshore trawl surveys [1978-2002, all years combined; seeReid et al. (1999) for details].
Page 28
/'I"_.
Little Skate Massachusetts Inshore Trawl Survey (1978- 2001)
Fall/juveniles
(<= 49 cm)
Number per tow 1-10
- 11-100
- 101-500 0 > 500 Massachusetts
.6~
- 0 0.
Og Figure 8. cont'd.
Page 29 Figure 9. Distribution and abundance of juvenile and adult little skate (8-51 cm TL) collected in Long Island Sound, based on the finfish surveys of the Connecticut Fisheries Division, 1984-1994 [from Gottschall et al. (2000)]. Circle diameter is proportional to the number of fish caught, and is scaled to the maximum catch (indicated by "max>").
Collections were made with a 14 m otter trawl at about 40 stations chosen by stratified random design.
Page 30 10=
April August n= 642 Tows - 21 jTows
,n -369
-39 10=
1000 10
[ T.y n-0 Tows-0 June October n -2,385 n-1.077 Tows - 45 Tow =,43 10=-
tl November n-!C n-0 T.w- TOWS MO 8 [0 12 14 ll IS 20 2'2 24 26 20 30 32 34 36 38 40 42 , 46 4850 8 101 14 16 18 20 22 24 20 28 3D 32 34 36 38 40 42 4, 'a4850 Figure 10. Monthly logl 0 length frequencies (cm) ofjuvenile and adult little skate collected in Long Island Sound, based on 4,473 fish taken in 148 tows between 1989-1990. From Gottschall et al. (2000).
Page 31 IKE !Abundance]
by Month Percent Occurrence by Month 90
--k'- i/
n 60 -
C 61 5,o\
70 r----!Bh MonthJ~ and Botto byp~ Tye:,oi Mn I B Abundance E. Percent Occurrence by Month and Bottom Type [by Month and Bottom Typel 3
C f-........... . .
C. - ...
80 C. V 0_, 7f 5 2C0
!Molh.. i ay 93.68, J;n t F?"727, 91s
.1= : u9 Sep 03 NC, --
.10o16 3-°':.63,600 5 543 :i4-F-Y32 2.17 .* "o *
- mud U --- r' * -*, --- U - ; 7, 82,7 1 911*"-
laos 16 667d . 7.6 3 ..: 71-...933.
1.4 ,,7-Al Abundance j by Month and Depth Interval Percent Occurrence 1by Month and Depth Interval1 2&
2.C 1,IS 0W 4 D MIonlo..
- 7,0907---I Au, "i76.04.
2240B . 7 7 'i ,,"*
0- 32, . ( 6"637 o "* o . .....
- 1
- 6...
.. . . . 815.. I- 5J2.n A,0 I.2 s2. F 6 7 7 iSO.O-1oV K60. . 61 3 5 ..31 5261 I 72.4 i .7 06 .
E3.1-182m
_:10 *.7.3m-L?.!p6 13 11 1C3 6 55 14i4 F0T 3 1.31 12-2...62' lOS9 460 2 420 A3.
02103,27 3ili 51.3 06.0 !4,i 70.7 52.9 7-. i TY S.8 .
T27.4km 7*j- 4-i 1,43
ýl0 i0i.7? 34 . 6.23"5* 0 301' 153?4.nI 4.0 66790. 761 76. I 6.7 3..4 5.3 Figure 11. Relative abundance (geometric mean catch/tow) catch/tow and percent occurrence (proportion of samples in which at least one individual was observed) for juvenile and adult little skate in Long Island Sound by month, month and bottom type, and month and depth interval. From Gottschall et al. (2000).
Page 32 74' 15 ' 74° 10 " 74" 05~ 74*0O0 730 55 LITTLE SKATE--Juveniles (<= 49 cm) \ -.Hudson River Winter (92 - 97)
Hudson/Raritan Trawl Survey R.~ New YorI .... 400 35 Fish Caught/station (excluding 0 catch):
Mean: 6 Min: 1 Max: 31
,z<Y~~
Length (cm): Min: 9 Max: 49 Staten ?4.
Island
.7.
1/
_4 4030
- . ' I S. , , Numbi 1-2 1 k.. (w*
..- '0 3-5 1 New Jerse y 6-10 ý4Q0*5~
>10 74* 05" 74' 000 55'40* 30" 74° 15 '74 10" 73' LITTLE SKATE--Juveniles (<= 49 cm) \, Hudson River Spring (92 - 97)
Hudson/Raritan Trawl Survey 7 . ** " New YorI
/ *'
Fish Caught/station (excluding 0 catch): N " *.
-40* 35 Mean: 5 Min: 1 Max: 58
. 0 -
Length (cm): Min: 21 Max: 49
- o* 9 A 0.
0 0
0 0
- - j 3--'-I
'*0* ~
Staten *0 0 .* 0.
Island 0 0.
- qg ~
@00
/ 0
- 0*
- 0 0 * . .. 0 ** .
- 0
- 0 op S
- 15. '>
. Number/Tow p..1 1-2 j,/~
- 3-5 New Jersey,
- 6-10 1400 25 i
>10 Figure 12. Seasonal distribution and abundance ofjuvenile little skate in the Hudson-Raritan estuary, based on Hudson-Raritan trawl surveys, 1992-1997 [all years combined; see Reid et al. (1999) for details].
Page 33 74' 15' 74* 10" 74 05" 74, 00 73° 55" LITTLE SKATE--Juveniles (<= 49 cm) \ -*-.-Hudson River /
Summer (92 - 96)
Hudson/Raritan Trawl Survey New York I Fish Caught/station (excluding 0 catch): ,40° 35 Mean: 4 Min: 1 Max: 11 Length (cm): Min: 35 Max: 48 IV Staten Island
-I-, '~
14Q0 30 Number/Tow
_p-
'0 1-2
- 3-5 New Jersey
- 6-10 '40°25
>10 74° 15' 74° 05" 7°00" 730 55
....... . . .......4 ............" "- r ¢ ...
.... 74° 10" LITTLE SKATE--Juve niles (<= 49 cm) ý-.-Hudson River Fall (92 - 96)
Hudson/Raritan Trawl Survey " /.** .. *New Yorlk '
Fish Caught/station (excluding 0 catch): *. . > N / Y .-. ,40 035 Mean: 7 Min: 1 Max :56
/I' '
. ~ 6 Length (cm): Min: 21 Max: 49 "
/- I
- E'-
-/
n/ I *- -we of
" "ll 0'I SO
- 0 Statei . . ..
Island 7-71" , Numb
/
o./ 3* .... 6 .. ., . *... ..
, . 5 O 0* 40* 30
- . o° *" * :
o..,I......
.2 .;
er/Tow 1-2 3-5 New Jersey .
140° 25 N J 6-10
>10 Figure 12. cont'd.
Page 34 750 30 ' 750 20' 75° 10 ' 750 00 740 50 LITTLE SKATE ]390 30" All Size Classes Combined Winter (1966 - 1999)
Delaware Bay Trawl Survey Average Number of Fish Caught and Percent Occurrence 7390 20 "
NJ 0.62 jy
<-I 15%
A' 2.50 36%
I 390 10 '
0.73 27%
2.32 2.00 41"% 100%
00' 3.13 0.69 2.33
)-<:; 47/% /
19% '12.20 33% L 47%
13.14 0.00 4.06 0% # Times 38% 43% Station Sampled
'-'I- t1_r'
" ... , 1.30*\ ~10 -22 . . . 38° 50 1%
0..0 31-40 Data Source: eo 41-50 Delaware Division of Fish &Wildilfe Henlopen,
- 51 -61
---. I-Figure 13. Seasonal distribution and abundance of juvenile and adult little skate in Delaware Bay, based on Delaware Division of Fish and Wildlife bottom trawl surveys from 1966-1999 (all years combined). Surveys were conducted monthly at 9-14 fixed stations, using a 9.1 m otter trawl towed for 20-30 min (for methods see Michels and Greco 2000).
Page 35 750 30 " 750 20 ' 750 10 ' 750 00 ' 74 50' LITTLE SKATE 1390 30" All Size Classes Combined Spring (1966 - 1999)
Delaware Bay Trawl Survey Average Number of Fish Caught and Percent Occurrence 390 20 NJ 0.00 0
0%
r~2~ ~
0.15 0
/ *7%/ :390 10' 0.63 0 1/
22%
/
/
/
/
1.71 0
0.00 43% 0%
/
'1390 00 0.84 8.40 1.67
, C'- 22% 66%
33% 5.88 0
56%
2.11 5.27 5.50 50% # Times 56% 65% Station Sampled DE +/- 1-5 3.36 10-22 1380 50
- 31 -40 o 41-50 Data Source: Cape Delaware Division of Fish &Wildilfe Henhopeni. e 51-61 Figure 13. cont'd.
Page 36 750 30 ' 750 20 " 750 10 ' 750 00 ' 740 50.'
LITTLE SKATE All Size Classes Combined 1390 30, Summer (1966- 1999)
Delaware Bay Trawl Survey Average Number of Fish Caught and Percent Occurrence
- 390 20 NJ
- 0o%
0%
1390 10 o.g2 2%
0.*I 0.00
\
2% 0% /
, .i39°00' 0.26 0.00 0.00 / ape ~
O0/0 0.50 0% a 0
8%/
0.00 0.00 # Times 0% 0%
11% Station Sampled DE 1-5 0.00 10-22 3850~
00/0 a 31 -40 0 41-50 Data Source: Cap 7 i Delaware Division of Fish &Wildilfe Henlopen
- 51-61 Figure 13. cont'd.
Page 37 750 30 ' 750 20 ' 750 10 ' 750 00 ' 740 50 '
LITTLE SKATE 390 30 All Size Classes Combined Fall (1966 - 1999)
Delaware Bay Trawl Survey Average Number of Fish Caught and Percent Occurrence 390 20' NJ r,5U 0.00 0 0%
0.84 0
16% 390 10 0.67 0
19%
1.6 0.00 N
27% 0%
390 00 0.94 0 0.12 1.60 17% 0 12%/ 5.29 0
40%
42% J 2.52 0.67 2.09 0 33% # Times 34% 33% Station Sampled DE +/- 1-5 1.17 10-22 380 50" 33%/o
- 31-40 o 41-50 Data Source: Cape Delaware Division of Fish &Wildilfe Henhlopen,
- 51-61
.......................... ............................ ................I............. .......
Figure 13. cont'd.
Page 38 Figure 14. Distribution of adult little skate collected during winter NEFSC bottom trawl surveys [1964-2002, all years combined; see Reid et al. (1999) for details]. Survey stations where adults were not found are not shown.
Page 39 Figure 15. Distribution and abundance of adult little skate collected during spring NEFSC bottom trawl surveys [1968-2002, all years combined; see Reid et al. (1999) for details].
Page 40 Figure 16. Distribution of adult little skate collected during summer NEFSC bottom trawl surveys [1963-1995, all years combined; see Reid et al. (1999) for details]. Survey stations where adults were not found are not shown.
Page 41 Fall/adultS
(> 49 cm)
Number per tow 1-10 9 1.1-100 S 101 - 1000
- > 1000 Little Skate
§3 NEFSC Bottom Trawl Surveys (1963- 2001)
Figure 17. Distribution and abundance of adult little skate collected during fall NEFSC bottom trawl surveys [1963-2001, all years combined; see Reid et al. (1999) for details].
Page 42 Little Skate Massachusetts Inshore Trawl Survey (1978- 2002)
Spring/adults
(> 49 cm) K Number per tow
- 1-10
- 11-100
- 101-500 G > 500 Massachusetts 0 N ntucke Figure 18. Distribution and abundance of adult little skate in Massachusetts coastal waters collected during the spring and autumn Massachusetts inshore trawl surveys [1978-2002, all years combined; see Reid et al. (1999) for details].
Page 43 Figure 18. cont'd.
Page 44 74005"' 74* 00' 730 55
[4.... 740
+..........{....15'
...........74°10'
. .. .......... +..
LITTLE SKATE--Adults (>= 50 cm) \ -tHuddson River ,*'
Winter (92 - 97)
Hudson/Raritan Trawl Survey New York- ,
i Fish Caught/station (excluding 0 catch): --- 40° 35 Mean: 1 Min: 1 Max:2 //
Length (cm): Min: 50 Max: 54 Staten Island
.N
...J z40* 30'
-'NN umber/Tow "0 1-2 1
-.-p...
1"U
- 3-5 1
> -\d' New Jersey
- 6-10 -A40 25"
>10 74° 15' 74 10" 74' 05 *
- 74_000 73q 55 LITTLE SKATE--Adults (>= 50 cm) , Hudson River Spring (92- 97)
Hudson/Raritan Trawl Survey
',New York Fish Caught/station (excluding 0 catch): '* 40 35 Mean: 1 Min: 1 Max: 2 Length (cm): Min: 50 Max: 51 Staten Island
-40" 30"
'p Number/fow IN C-1-2 (K
- 3-5
($J New Jersey
- 6-10 400 25'
>10 Figure 19. Seasonal distribution and abundance of adult little skate in the Hudson-Raritan estuary, based on Hudson-Raritan trawl surveys, 1992-1997 [all years combined; see Reid et al. (1999) for details].
Page 45
.* .........74* 15 i ... ........ .. :.. . ... 74' 10'
. . .. . i . . . ..:. -.. .-------..
74' 05 74°00 " 73 55 "
LITTLE SKATE--Adults (>= 50 cm) \ .-*Hudson River Summer (92 - 96)
Hudson/Raritan Trawl Survey New York ,"
Fish Caught/station (excluding 0 catch):
Mean: 1 Min: 1 Max: 1
/ 4035
^/
Length (cm): Min: 50 Max: 50 -y
/. /
Staten Island N
- 140°30*
\ Numb er/Tow
)Oo
\L 1-2 i 3-5 v-I New Jersey 6-10 -140° 25"
>10 74* 15" 74' 10" 730 35
- .... .. ...... 74' 05 74' 00' LITTLE SKATE--Adults (>= 50 cm) N -\-,Hudson
\ .. River Fall (92 - 96)
Hudson/Raritan Trawl Survey
/
/"
- New Yor
- .- .....4Q0 35 Fish Caught/station (excluding 0 catch):
Mean: 1 Min: 1 Max:2 // _z7~-------
- Length (cm): Min: 50 Max: 59 Staten Island A40030"
'4) 0-
'~\ Numi~eriiow mber/Tow 1-2
- 3-5 1 New Jersey N
- 6-10 .400 25" N
'7 >10 N----- \
Figure 19. cont'd.
Page 46 Little Skate NEFSC Bottom Trawl Survey Spring/Juveniles 40 [3 Trawls N=10537 30
- Occurrence N=4601 EoCatch N=190907 2 20 n 10 0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Bottom Temperature (°C)
[I Trawls N=12193 50
- Occurrence N=5293 40 30 o Catch N=225863 3 20 10 0
Bottom Depth (m)
[I Trawls N=1959 40
- Occurrence N=971 C -30 2 20-
[3 Catch N=70595 D 10 0 22 26 27 28 29 30 31 32 33 34 35 36 37 Salinity (PPT)
Figure 20. Spring and fall distributions of juvenile little skate and trawls relative to bottom water temperature, depth, and salinity based on NEFSC bottom trawl surveys (1963-2002; all years combined). White bars give the distribution of all the trawls, black bars give the distribution of all trawls in which little skate occurred, and gray bars represent, within each interval, the percentage of the total number of little skate caught.
Page 47 Little Skate NEFSC Bottom Trawl Survey Fall/Juveniles 20 0 Trawls N=11844 0 Occurrence N=3566 15 O Catch N=55895 2 10 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Bottom Temperature (°C)
[I Trawls N=13543 25 0 Occurrence N=4036 20 a 15 10 S10_
5 0
n~rlI E)Catch N=63689 0 0 0 0 0 Co C
oC4 C ~)~~CD ~0)C D 0 C 0
~(00 0 (0
0 0
0 0
0 0
0 0
0 0
0-N C4 COY) ,O.
--- (' ov-- - Deph Bottom Depth (in)
[3 Trawls N=1956 60 0 Occurrence N=711 E40 EoCatch N=10517 20
¶20-27 29 30 31 32 33 34 35 36 37 Salinity (PPT)
Figure 20. cont'd.
Page 48 Little Skate Massachusetts Inshore Trawl Survey Spring/Juveniles 30 -
0 Trawls N=2312 25-
- Occurrence N=1679 1 20 a) o Catch N=1 19534 2 15 n) 10 0 '1r-i 7 -T 7 L1, 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Bottom Temperature (*C)
[I Trawls N=2385 40-
- Occurrence N=1 732 30 [3 Catch N=1 23400 C
a) 2 20 a)
CL10-0-
C L2) 0 LO 0 oCt O O 0 M 0 L B(oN et (m WW Bottom Depth (in)
Figure 21. Spring and fall distributions of juvenile little skate and trawls relative to bottom water temperature and depth based on Massachusetts inshore trawl surveys (1978-2002, all years combined). White bars give the distribution of all the trawls, black bars give the distribution of all trawls in which little skate occurred, and gray bars represent, within each interval, the percentage of the total number of little skate caught.
Page 49 Little Skate Massachusetts Inshore Trawl Survey Fall/Juveniles 25 o Trawls N=2067 20
- Occurrence N=1 346
- Catch N=73738 Q 10 r 5-4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 Bottom Temperature (°C) 0 Trawls N=2156 30 0 Occurrence N=1414 25 E 20 [] Catch N=77792 2 15 o~10 5
0 U) 0 L) aC D U1) 0 U)
( 1 C U)0 C0
- N J C) C?) U)? C?
- N MN CL M ~ 'U o C Bottom Depth (in)
Figure 21. cont'd.
Page 50 Winter 20 C
] Ei Trawls N=468 m Occurrence N=261 10 n) 13 Catch N=1 596 0 I I I ýfý i ili& - '. - I ,
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Depth (m) 40 -
30
- Trawls N=462 S20
- Occurrence N=258 0) 12 Catch N=1 574 10 Anl 0
0 2 4 6 8 10 12 14 16 i8 20 22 24 26 28 Temperature (0C) 20 L)Trawls N=466 il1ld[L ,
a) 10 MOccurrence N=260 a-)
M-Catch N=1 592 0
0 2 4 6 i~'1i 1ý1 IRI 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 VbrL Salinity (PPT) 40 30
- Trawls N=265 2 20
- Occurrence N=161
[3 Catch N=1 143 10 0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 DO (PPM)
Figure 22. Seasonal distributions ofjuvenile little skate and trawls relative to bottom water temperature, depth, salinity, and dissolved oxygen based on NEFSC Hudson-Raritan estuary trawl s~urveys (1992-1997; all years combined). White bars give the distribution of all the trawls, black bars give the distribution of all trawls in which little skate occurred, and gray bars represent, within each interval, the percentage of the total number of little skate caught.
Page 51 Spring 30 C: 20 LI Trawls N=330 a) m Occurrence N=21 1 10 ia Catch N=981 0
0 2 4 6 8 10 12 14 16 18 20 22. 24 26 28 Depth (m) 30 E 20- D]Trawls N=326 a) I [1 Occurrence N=208 I
U a)
~~ Catch N=976 0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Temperature (°C) 30 -
20 -]Trawls N=326 I Occurrence N=208 n 10 .1Catch N=976 0-0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 Salinity (PPT) 30 E 20 U
n 10
-I E E
-]Trawls N=177 0 Occurrence N=130
-1Catch N=644 0-0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 DO (PPM)
Figure 22. cont'd.
Page 52 Summer 40 30 E:Trawls N=356 a)
U 20
- Occurrence N=17 a,
a-
- Catch N=75 10 0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Depth (m) 40 30 D1Trawls N=352 a) 2 20 ii U Occurrence N=17 al)
El Catch N=75 10 0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28
'Temperature (0C) 30 C
20 EDTrawls N=347 a)
{-_
- Occurrence N=16
- Catch N=67 10 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34' 36 38 Salinity (PPT) 40 30 20 10 I 1 LI Trawls N=215 0 Occurrence N=13 El Catch N=60 10
_ ~ I]
0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 DO (PPM)
Figure 22. cont'd.
Page 53 Fall 30
-E 20 oi Trawls N=586 n1 o Occurrence N=416 a) Ei Catch N=2750 (L10~
0-0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Depth (m) 20 ElTrawls N=570 a) 10 - 0 Occurrence N=403 a) a_ iEI Catch N=2661 0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 (0C)
Temperature 20 -
11 Trawls N=532 0
(D 10 - 0 Occurrence N=375 n) fu Catch N=2573 0-0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 Salinity (PPT) 30 20 ElTrawls N=458 II C.,
a) 0 Occurrence N=336 (3 Catch N=2449 0-
~rj~ IF01 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 DO (PPM)
Figure 22. cont'd.
Page 54 Winter 30 20 n- Trawls N=1 66 h~IL~1i I~IL~i~
M Occurrence N=52 a) El Catch N=617 0 n 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Depth (m) 50 40 1
-$ LI Trawls N=166 U) 30 0_ m Occurrence N=52 20 Li Catch N=617 10 0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Temperature (OC) 30 20 11 n1nIf 0 12 14 161 8 20 22 24262 LI Trawls N=1 57 1
C-,. m Occurrence N=52 U)_
El Catch N=617 10 rdJn 0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 Salinity (PPT) 60 50 40 *i Trawls N=125 a)
U) 30
- Occurrence N=50 a-)
a- 20 [ECatch N=608 10 0
- 0. 1 2 3 4 .5 6 7 8 9 10 11 12 13 14 15 DO (PPM)
Figure 23. Seasonal distributions of juvenile and adult little skate and trawls relative to bottom water temperature, depth, salinity, and dissolved oxygen based on Delaware Division of Fish and Wildlife trawl surveys from 1966-1999 (all years combined). White bars give the distribution of all the trawls, black bars give the distribution of all trawls in which little skate occurred, and gray bars represent, within each interval, the percentage of the total number of little skate caught.
Page 55 Spring 30 20- - Trawls N=378 C
U, I Occurrence N=1 16 C-,
- 0) -, Catch N=737 10 0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Depth (m) 20 C)
-1Trawls N=373 U,)
10 N Occurrence N=1 15 C-,
13Catch N=733 0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 0
Temperature ( C) 30 -
~20 El Trawls N=374 m Occurrence N=114 E-Catch N=730 0-10 0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 Salinity (PPT) 40 30
- Trawls N=312
- Occurrence N=97 ILIrký 2 20 E3Catch N=608 10 0- Fý-F6 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 DO (PPM)
Figure 23. cont'd.
Page 56 Summer 60 50 40 El Trawls N=512 C) 30 o Occurrence N=13 03 D Catch N=93 20 10 0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 1 Depth (m) 50 40 11 Trawls N=509 30 C-) o Occurrence N=13 C)L 20 I,11iFLF,IBItýnj D, Catch N=93 10 0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Temperature (0C) 40 30 11 Trawls N=498 2 20
- Occurrence N=1 3 10 LI Catch N=93 10
' " .1 1[- i r, 1ý11111,lflý I in I H 11' 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 Salinity (PPT) 50 40 LI Trawls N=4115 30
- Occurrence N=1 3 Qa 20 *I Catch N=93 10 0~
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 DO (PPM)
Figure 23. cont'd.
Page 57 Fall 30 -
C 20 o1 Trawls N=422 0)
U N Occurrence N=93 0) 10 El Catch N=632 0
0 2 4 6
,I 11ii,11 8 10 12 14 k IJ1rc 16 18 20 22 24 26 28 Depth (m) 40 30-o Trawls N=405 2 20
- Occurrence N=93 Ol Catch N=632 10 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Temperature (0C) 40 30 I
o1 Trawls N=399 2 20
- Occurrence N=89
- Catch N=624 10 0 n n-nM n n 6nnri I I 0 2 4 6 8 1012 14 16 18 20 22 24.26 28 30 32 34 36 Salinity (PPT) 70 60 4:
50 C
O Trawls N=341 40 U
- Occurrencec N=82
- 0) 30 0~ O Catch N=593 20 10 0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 DO (PPM)
Figure 23. cont'd.
Page 58 Little Skate.
NEFSC Bottom Trawl Survey ISpring/Adults 50 [:]Trawls N=1 0537 40 0 Occurrence N=1450 30 El Catch N=4627 Q 20 10 0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Bottom Temperature (°C) 0 Trawls N=12193 20 MOccurrence N=1 646 15 CU 0 Catch N=5195 o 10 05 0
0 0 0 0a 0 0 0 CDc L L LrI 0 0 0 0
~
1ý L?~ I I?Ný ? 1 CN 0 CD,~ 0
- omDep Bot (m)
Bottom Depth (in)
[I Trawls N=1959 80 0 Occurrence N=262 60 0 Catch N=836 40 20
[J-j 26 27 28 29 30 31 32 33 34 35 36 37 Salinity (PPT)
Figure 24. Spring and fall distributions of adult little skate and trawls relative to bottom water temperature and depth based on NEFSC bottom trawl surveys (1963-2002; all years combined). White bars give the distribution of all the trawls, black bars give the distribution of all trawls in which little skate occurred, and gray bars represent, within each interval, the percentage of the total number of little skate caught.
Page 59 Little Skate NEFSC Bottom Trawl Survey Fall/Adults 25 [I Trawls N=11844 20 0 Occurrence N=1313 C
0.)
15 [3 Catch N=4095 t-) 10 5
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Bottom Temperature (°C) 20-
- Trawls N=13543
- Occurrence N=1486 15-EoCatch N=4594 a)
CL 10
.0..
5 0 n 0 o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 N) C~) C1. ) ) -: D C:CD 0) N~ C D cD 0 0 0 0
. C? ) MA)
- U- C- C'- C-)' .- 1 Depth
-M C cN Bottom Depth (in) 50 0] Trawls N=1 956 40 N OccurrenceN=238 30 [u Catch N=802
ýB20!
10-I 27 29 30 31 32 33 34 35 36 37 Salinity (PPT)
Figure 24. cont'd.
Page 60
'Little Skate Massachusetts Inshore Trawl Survey
$pring/Adults 30 [3 Trawls N=2312 25 0 Occurrence N=863 S20 O Catch N=1 2700 10 2 5 0) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Bottom Temperature (°C) o Trawls N=2385 30
- Occurrence N=894 25
~20 I rL [3 Catch N=1 3204 2 15 n10 5
0 II r -IULLL hliFlk4o.
u? 2R 0 LO 0 LO 0 LO 0 L" 0 O 0 LO 0 O
, 0- - 6 - c o) :;, LW (0 , (0 (o oNtNoM Dp ( (0 Bottom Depth (in)
Figure 25. Spring and fall distributions of adult little skate and trawls relative to bottom water temperature and depth based on Massachusetts inshore trawl surveys (1978-2002, all years combined). White bars give the distribution of all the trawls, black bars give the distribution of all trawls in which little skate occurred, and gray bars represent, within each interval, the percentage of the total number of little skate caught.
Page 61 Little Skate Massachusetts Inshore Trawl Survey Fall/Adults 15 [I Trawls N=2067 N Occurrence N=709 10 0 Catch N=10582
_ 5 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 Bottom Temperature (0C) 0 Trawls N=2156 30-E Occurrence N=739 25 E 20 0 Catch N=11032 a) 2 15 10 5
0 U? 0O 0O 0O
-ý C6
- C C,
04 CIO : II? ý'(00- C Bottom Depth (in)
Figure 25. cont'd.
Page 62 Winter 40 -
30 C
LI Trawls N=468 L2 20 N Occurrence N=16' 10 0 Catch N=17 20 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Depth (m)
At*
30 FL Trawls N=462 CD a3_20 0 Occurrence N=15 El Catch N=16 10 0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Temperature (°C) 20 C
ElTrawls N=466 a)
U. 10
- Occurrence n=16 a,
LI Catch N=17 0
0 24 6 8 10 12 14 16 18 20 ý2 24 26 28 30 32 34,,36 38 Salinity (PPT)
I+u 30.
ELITrawls N=265 U
a,_ 20 1
- Occurrence N=8 0, Catch N=9 10 0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 DO (PPM)
Figure 26. Seasonal distributions of adult little skate and trawls relative to bottom water temperature, depth, salinity, and dissolved oxygen based on NEFSC Hudson-Raritan estuary trawl surveys (1992-1997; all years combined). White bars give the distribution of all the trawls, black bars give the distribution of all trawls in which little skate occurred, and gray bars represent, within each interval, the percentage of the total number of little skate caught.
Page 63 Spring 80 70-60-
[] Trawls N=330 a, 50-C C-) 40 0 Occurrence N=9 a,
-I I_
30 El Catch N=I 1 20 10 0 i I.i "
I n --El l II -I 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Depth (m) 40 30 El Trawls N=326 o 20 N Occurrence N=9 a) EDCatch N=1 1 0-0 2 4 6 lh
ýit, ,ýI 8 10 12 14 16 11 18 20 22 24 26 28 Temperature (°C) 50 -i 40-cý 30 Ej Trawls N=326 N Occurrence N=9 20 10 0
0 2 4 6 r[F I i ýd-ý 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 Salinity (PPT) 11 Catch N=1 1 40 30 El Trawls N=1 77 W 0 Occurrence N=6
-IIi F a- 20 -
El Catch N=7 10 0! I-,J F 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 DO (PPM)
Figure 26. cont'd.
Page 64 Summer 50 40 C:
- Trawls N=356 30
- Occurrence N=2 a-20 El Catch N=2 10 0
0 2 4 *6 8 10 12 14 16 18 20 22 24 26 28 Depth (m) 50 C
a)
C-)
a) 40 30 20 I 1 D Trawls N=352
- Occurrence N=2 E Catch N=2 10 0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28
)
Temperature (0C 50 40 C:
- JTrawls N=347 a) 30 a-'
- Occurrence N=2 20
- Catch N=2 10 0 0I-0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 Salinity (PPT) 50 40 D Trawls N=215 C 30 o Occurrence N=2 0- 20 oi Catch N=2 10 0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 DO (PPM)
Figure 26. cont'd.
Page 65 Fall 30 20 Li Trawls N=586 n Occurrence N=19 El Catch N=21 n 10 0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Depth (m) 40-I 30 Ei Trawls N=570 2 20 o Occurrence N=18 El Catch N=20 10-0 I 0 2 4
F 111* l I 6
i] I 8
l [R
- I 10 12 l il v ]ý:I 14 l nI ýý,
I. ý 16
. I;. -lq 18 20 22 24 26 28 Temperature (0C) 20 11 Trawls N=532 10 m Occurrence N=1 8 13 Catch N=20 0
0 2
4 6
8 i~
.. .,- /. ,- .:- v -. ,- .:.-,..--.-
10 12 14 16 18 20 22 24 26 28 30 32 34 36 38
~fIliu1n
.- v - .i- ,,.- ., ..... ,.- . . . .
Salinity (PPT) 50 40 E)Trawls N=458 30o
- Occurrence N=15.
0 20 Li Catch N=17 10 0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 DO (PPM)
Figure 26. cont'd.
Page 66 Gulf of Maine, Georges Bank, Southern New England, Mid-Atlantic Bight 18000 10 16000 - Skate complex, commercial landings (mt) 9 14000- Survey index of little skate biomass 8 C 12000 *"
0 C0 10000 E .
- 5 u) 8000 ,D.
" 600"* *' ' *: =
6000 ,
4000 ., 1 20 0 o (0 't " O0 0~ (04 " (*- 0 (N "* (0 C 0 (N *1 CO
- 0 CO CO (0 (0 (0D N- N N. N',. 0 (O (0 (O CO 0 O* 0)
CO 0
- 0) 0 C* O ~0*. I.
O* O* 0) 0) 0) 0) 0 0) 0) 0) 0 0) 0) 0 0 Year Figure 27. NEFSC spring survey index of little skate biomass and commercial landings of the seven species skate complex from the Gulf of Maine to the Mid-Atlantic Bight.