ML072060414
Text
Fish and Wildlife Service U.S. Department of the Interior Coastal Ecology Group Waterways Experiment Station U.S. Army Corps of Engineers T~s I
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FWS/OBS-82/11.10 TR EL-82-4 Ocotber 1993 Species Profiles:
Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Mid-Atlantic)
ATLANTIC SILVERSIDE by Clemon W. Fay, Richard J. Neves, Department of Fisheries and Virginia Polytechnic Institute Blacksburg, VA and Garland B. Pardue Wildlife Sciences and State University 24061 Project Manager Larry Shanks Project Officer Norman Benson National Coastal Ecosystems Team U.S.
Fish and Wildlife Service 1010 Gause Boulevard
- Slidell, LA 70458 This study was conducted in cooperation with Coastal Ecology Group U.S. Army Corps of Engineers Waterways Experiment Station Performed for National Coastal Ecosystems Team Division of Biological Services Fish and Wildlife Service U.S. Department of the Interior Washington, DC 20240
CONVERSION FACTORS Metric to U.S. Customary Multiply To Obtain, millimeters (mm) centimeters (cm) meters (i) kilometers (km) 0.03937 0.3937 3.281 0.6214 10.76 0.3861 2.471 inches inches feet miles square meters (mL) square kilometers (kin2) hectares (ha) liters (1) cubic meters (m3) cubic meters milligrams (mg) grams (gm) kilograms (kg) metric tons (mt) metric tons (mt) kilocalories (kcal)
Celsius degrees square feet square miles acres 0.2642 35.31 0.0008110 0.00003527 0.03527 2.205 2205.0 1.102 3.968 1.8(C6) + 32 gallons cubic feet acre-feet ounces ounces pounds pounds short tons BTU Fahrenheit degrees U.S. Customary to Metric inches inches feet (ft) fathoms miles (mi) nautical miles (nmi) square feet (ft')
acres square miles (mi 2 )
gallons (gal) cubic feet (ft acre-feet ounces (oz) pounds (lb) short tons (ton)
BTU Fahrenheit degrees 25.40 2.54 0.3048 1.829 1.609 1.852 0.0929 0.4047 2.590 3.785 0.02831 1233.0 mril I imeters centimeters meters meters ki 1 ometers kilometers square meters hectares square kilometers liters cubic meters.
cubic meters grams kilograms metric tons kilocalories Celsius degrees 28.35 0.4536
- 0. 9072
- 0. 2520 0.5556(F° - 32)
CONTENTS Page CONVERSION TABLE............................
i PREFACE.......................................................
iv ACKNOWLEDGMENTS v
NOMENCLATURE/TAXONOMY/RANGE....................................
1 MORPHOLOGY/IDENTIFICATION AIDS...............
I REASON FOR INCLUSION IN SERIES.....................
3 LIFE HISTORY 3
Reproductive Physiology/Strategy.............
3 Spawning-General......
4 Spawning Periodicity..................................
4 Spawning Behavior.................................................
5 Dissolved Oxygen Depletion (Spawning)......
5 Eggs 5
Egs.......................................
5 Yolk-Sac Larvae.
6.............................6 Larvae..................................................
6 Juveniles/Adults....
7 GROWTH CHARACTERISTICS...
8 THE FISHERY....................
9 Commercial and Recreational Fisheries.
9 Population Dynamics 9
ECOLOGICAL ROLE.....................
9 Food Habits/Feeding Behavior...................
I.....
9 Predators........................................
10 Competitors..........................................
10 Role as Estuarine Biomass Exporter...........
10 ENVIRONMENTAL REQUIREMENTS...............
10 Temperature.....................
10 Salinity................
I.11 LITERATURE CITED..................
12 iii
PREFACE This species profile is one of a series on coastal aquatic organisms, principally fish, of sport, commercial, or ecological importance.
The profiles are designed to provide coastal managers, engineers, and biologists with a brief comprehensive sketch of the biological characteristics and environmental require-ments of the species and to describe how populations of the species may be expected to react to environmental changes caused by coastal development.
Each profile has sections on taxonomy, life history, ecological role, environmental requirements, and economic importance, if applicable.
A three-ring binder is used for this series so that new profiles can be added as they are prepared.
This project is jointly planned and financed by the U.S. Army Corps of Engineers and the U.S. Fish and Wildlife Service.
Suggestions or questions regarding this report should be directed to:
Information Transfer Specialist National Coastal Ecosystems Team U.S.
Fish and Wildlife Service NASA-Slidell Computer Complex 1010 Gause Boulevard
- Slidell, LA 70458 or U.S.
Army Engineer Waterways Experiment Station Attention:
WESER Post Office Box 631 Vicksburg, MS 39180 This series should be referenced as follows:
U.S.
Fish and Wildlife Service.
1983.
Species profiles:
life histories and environmental requirements of coastal fishes and invertebrates.
U.S.
Fish and Wildlife
- Service, Division of Biological
- Services, FWS/OBS-82/11.
U.S. Army Corps of Engineers, TR EL-82-4.
This profile should be cited as follows:
- Fay, C.W.,
R.J. Neves, and G.B.
Pardue.
1983.
Species profiles:
life histories and environmental requirements of coastal fishes and invertebrates (Mid-Atlantic)
Atlantic silverside.
U.S. Fish and Wildlife Service, Division of Biological
- Services, FWS/OBS-82/11.10.
U.S.
Army Corps of Engineers, TR EL-82-4.
15 pp.
iv
ACKNOWLEDGMENTS We are grateful for the review by Dr. David Conover, State University of New York at Stony Brook, Long Island.
V
Figure 1. Atlantic silverside.
ATLANTIC SILVERSIDE NOMENCLATURE/TAXONOMY/RANGE Scientific name.
Menidia menidia Preferred comrion name.
Atlantic sil-verside (Figure 1).
Other common names.. Spearing, sper-Iing, green smelt, sand smelt, white bait, capelin, shiner (Bigelow and Schroeder 1953).
Class................
.Osteichthyes Order.
..Atheriniformes Family....
Atherinidae Geographical range:
Atlantic coast of North America, from just north of 47 degrees north latitude, in New Brunswick, Nova Scotia, and the Magdalen Islands (Gosline 1948),
south to Volusia County, Florida (Leim and Scott 1966).
Wide-spread and abundant in coastal waters and tributaries of the entire area (Massmann 1954; Rob-bins 1969)
(see Figure 2 for a map of the mid-Atlantic distribu-tion of Atlantic silverside).
MORPHOLOGY/IDENTIFICATION AIDS The following information was taken from summaries in Martin and Drewry (1978),
where a
detailed morphological description is available.
I
N.Y.
I, N.J.
i PHILADELPHIA ATLANTIC OCEAN MILES 0
50 100 0
50 100 KILOMETERS CHESAPEAKE BA Y Offshore distribution 0
W Area of high abundance in winter S
Area of high abundance in spring, summer, and fall IARLE
,SoUND
/L.
' O'kCAPE HA TTERAS Figure 2.
Mid-Atlantic distribution of the Atlantic silverside.
The offshore distribution boundary is representative of the majority of Atlantic silverside populations; however, National Marine Fisheries Service (NMFS) trawl surveys have reported Atlantic silversides offshore to 180 km (112 mi) in spring/sum-mer and to 150 km (93 mi) in winter (Conover and Murawski 1982).
2
Dorsal spines 3-7 (mean 4.6),
dorsal rays 7-11 (mean 8.6),
anal spines 1,
anal rays 19-29 (mean 23.6).
Lateral line scales between pectoral insertion and caudal fin 34-47 (mean 40.7).
Body elongate,
- slender, rounded to dorsally depressed.
Head triangu-lar, dorsally flattened; mouth terminal and slightly
- superior, maxillary not extending to front of eye.
Scales cycloid with entire
- margins, well imbricated.
.. Color: Dorsally translucent green to greenish-yellow; laterally
- silver, with well defined, longitudinal, metal-lically lustered, silver-colored stripe, edged above by dark line; ventrally white. Dorsal and caudal fin rays uni-formly spotted, and caudal fin usually tinged with yellow.
REASON FOR INCLUSION IN SERIES The Atlantic silverside is an important forage fish (Merriman 1941; Bayliff 1950; Bigelow and Schroeder 1953),
reaching high abundance in the shore-zone of salt marshes, estuaries and tidal creeks. This species is often the most ab.undant fish encountered in these areas (Mulkana 1966; Richards and Castagna 1970; Briggs 1975; Anderjson et al.
1977; Hillman et al.
1977).'
The importance of Atlantic silver-
- sides as forage for such piscivores as striped bass (Morone saxatilis),
Atlantic mackerel (Scomber scombrus),
and bluefish (Pomatomus saltatrix) has been well documented (Bayliff 1950.;
Bigelow and Schroeder 1953; Schaefer 1970).
Presumably then, the Atlantic silverside should be a key member of the estuarine food
- web, but until
- recently, little study.
has been devoted to its life
- history, particularly
-environmental require-ments (Conover and Ross 1982).
LIFE HISTORY Reproductive Physiology/Strategy Atlantic silversides are hetero-sexual;
- however, an. unusual mecha-nism of sex determination in this species has been identified.
Adult gender is apparently controlled by interaction of female parent genotype with water temperature regime during a specific and critical period of larval development (see LIFE HISTORY--Lar-vae section)
(Conover and Kynard 1981).
Reproductive mode varies from polygamy (Middaugh et al.
1981) to extensive promiscuity (Conover 1982).
Both sexes of the Atlantic silver-side mature by age
- 1.
Although 2-year-old specimens have been reported (Bayliff 1950; Conover and R6ss 1982),
apparently most adults die after completion of their first spawn-ing (perhaps because of physiological exhaustion)
(Conover and Ross 1982),
or are lost to other causes of mortal-ity before they reach age
- 2.
In Essex Bay, Massachusetts,.
2-year-old fish constituted 0.2% and 1.0%,
respectively, of the 1977 and 1978 spawning populations.
Both males and females were represented by 2-year-old individuals (Conover and Ross 1982).
Females are larger and heavier than males of the same age (Conover 1982),
a fact that may be related to the unusual mechanism of sex determination discussed in the LIFE HISTORY -Larvae section.
Little is known concerning fre-quency of spawning within a
season for an individual silverside.
A fre-quency of four or five times per female per season was reported in Conover (1979).
In laboratory studies of spawning activities of female Atlan-tic silversides in 85-1
- aquaria, 3
individual females spawned up to 20 separate times in a
season (Conover 1982).
The applicability of this spawning frequency to field environ-ments is
-unknown, since (1) ripe females were placed in test tanks individually, rather than in large schools as in natural environments; (2) spawning periodicity of an indi-vidual female was every 1 to 3 days, not coinciding with normal lunar cycles or observed natural spawning periodicity; and (3) no "tide-like" influences were applied in the labora-tory tests.
Fecundity of Atlantic silversides ranged from 4,725 to 13,525 total eggs.
The average number of eggs actually spawned in a
season was 4,500 to 5,000 per female.
It was noted that these eggs were probably released in four or five separate spawning events per female per year (Conover 1979).
A much lower fe-cundity estimate, from earlier studies, was an average of 500 eggs (Hilde-brand 1922) and a range up to 1,400 eggs (Kendall 1902).
Spawning-General Atlantic silversides spawn in the intertidal zone of nearly all major estuaries and tributaries within, their geographic range (Hildebrand 1922; Wang 1974).
Spawning areas are sea-ward of locations used by Menidia beryllina (inland silverside),
a closely related species (Smith 19.71).
The major spawning season of Atlantic sil-versides in the mid-Atlantic region extends from late March through June (Nichols 1908; Hildebrand 1922; Mid-daugh 1981).
Ripe females have been collected through July in Massachu-setts (Kuntz and Radcliffe 1917; Wil-liams and Shaw 1971) and in Chesa-peake Bay (Bayliff 1950; Rasin 1976),
at water temperatures between 130 and 30*C (550 and 860F)
(Middaugh and Lempesis 1976).
Spawning began at temperatures between
.160 and 200 C (610 and 680 F) in South
- Carolina, over a 3-year-period (Middaugh 1981).
Initiation of spawning is probably determined by water temperature, photoperiod, or, both (Middaugh and Lempesis 1976),
in conjunction with high tide and appropriate lunar phase during the spring months (Middaugh 1981; Conover 1982).
Spawninq Periodicitv Menidia menidia is one of over 50 fish species known to have lunar-related spawning cycles (.Johannes 1978; Conover 1982).
Spawning occurs strictly during daylight hours in large
- schools, and coincides with high tide (Middaugh 1981).
The first spawning activity usually occurs at a
new or full moon in early spring, and is fol-lowed by spawning peaks at approxi-mately 14-(Conover 1982) or 15-day (Middaugh 1981) intervals.
Some spawning activity was observed on days other than those of new or full moon (Middaugh 1981),
but up to 90t of the spawning within each 14-to 15-day stratum occurred over 1-(Conover 1982) to 3-day (Middaugh 1981) periods.
Some differences in spawning periodicity between South Carolina and Massachusetts populations of, Atlantic silverside have been reported.
Conover (1982) concluded that spawning periodicity in Massa-chusetts was highly correlated to the lunar phase, and that spawning inten-sity was dependent on relative height of a
given high tide.
In
- contrast, Middaugh (1981) found that the great-est correlation in South Carolina pop-ulations was between spawning perio-dicity and the coincidental occurrence of sunrise and high
- tide, approxi-mately every 15 days.
Days of high tide at sunrise also coincided fairly closely with new and full lunar phases during spring months.
Regardless, the periodicity-lunar phase correlation was not as high as the periodicity-sunrise and high tide correlation in the South Carolina population.
Addi-
- tionally, relative height of the high tide was not correlated with spawning 4
intensity (Middaugh 1981).
During spring high
- tides, the greatest spawning intensity was observed at the slack (Middaugh 1981) or ebbing (Conover 1982) stages.
It is apparent from studies of Atlantic silverside spawning periodicity that specific.
mechanisms and adaptive significance of lunar-related spawning cycles are poorly understood (Conover 1982).
Spawning Behavior Middaugh et al.
(1981) described.
spawning behavior of Atlantic silver-sides in South Carolina.
One-half to 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> prior to a spawn, a single large school or several smaller schools of adults appeared 10 to 30 m (33 to 98 ft) offshore, adjacent to the eventual spawning site.
Schools swam parallel to shore, gradually moving shoreward with the flood stage until the leading edge of the school was 2 to 3 m (6 to 10 ft) from shore. Positions in relation to shore and swimming speed of the school were maintained until just before peak high tide, when several individuals moved suddenly into flooded shoreline vegetation, followed by the remainder of the spawning school.
Eggs were released as a
female crossed the axis of a potential attachment substrate such as a cord-grass plant. One to several males fol-lowed closely and deposited milt. Sev-eral variations on this general behavioral pattern were described in Middaugh et al.
(1981) and Conover (1982),
including spawning in aban-doned fiddler crab (Uca pugilator) burrows.
Dissolved Oxygen Depletion (Spawning)
Middaugh (1981) and Middaugh et al.
(1981) found that extremely high spawning densities, commonly observed during peak Atlantic silver-side spawning
- episodes, temporarily depleted dissolved oxygen concentra-tions in the immediate area of the most intense spawning activity.
Dissolved oxygen isopleths coincided closely with density gradients of spawning fish within a
school.
In an unusually intense spawning event on 30 April
- 1976, dissolved oxygen dropped from 6 mg/I to 0.7 mg/I in the center of the spawning mass.
An interesting consequence of this dissolved oxygen depletion was reported (Middaugh 1981).
Predators such as small bluefish and spotted seatrout (Cynoscion nebulosus),
sur-rounding spawning schools of Atlantic silversides, were unable to penetrate past the 4.0 mg/I and 2.5 mg/I dis-solved oxygen isopleths, respectively.
This apparently limited or prevented predation on the heaviest concentra-tions of Atlantic silversides during the time of peak spawning (Middaugh 1981).
The oxygen depletion in combi-nation with the energy drain, associ-ated with spawning appeared to affect the spent silversides (Middaugh 1981).
Spent fish from intense spawning events were observed offshore from spawning beds in tight but nonschool-ing aggregations, and appeared to be stuporous and in a state of physiolog-ical recovery. These stuporous aggre-gations could be approached by man, and presumably by predators, with relative ease.
Eggs Eggs of the Atlantic silverside generally range from 0.9 to 1.2 mm 1 in diameter (Wang 1974; Middaugh 1981),
though diameters up to 1.5 mm have been reported (Tracy 1910; Leim and Scott 1966).
Eggs are transparent, yellow to green, and have 5 to 12 large oil globules and numerous small globules (Kuntz - and Radcliffe 1917; Hildebrand 1922).
Eggs are demersal, adhesive, and found in shallow waters of estuarine intertidal zones (Kuntz and Radcliffe 1917; Hildebrand 1922; Middaugh 1981).
Substrates for egg attachment are submerged vegetation (Bayliff 1950),
particularly eelgrass (Middaugh 1981),
'25.4 mm = 1 inch.
5
cordgrass (Middaugh et al.
1981),
and filamentous algae (Conover 1982).
Sand (Wang 1974) and beach trash.
(Nichols 1908) may also harbor attached" eggs. Studies in Salem Har-bor, Massachusetts, indicated that egg attachment substrates there were more specific than those described for other silverside populations. Only algal mats of the filamentous brown algae Pilay-ella littoralis and Entermorpha spp.
were used, even though these algae were growing among various aquatic vascular plants such as Spartina alterniflora (Conover 1982).
Egg attachment is reinforced by several filaments (Hildebrand 1922; Middaugh 1981; Conover 1982) origi-nating from a
specific area of the chorion (Kuntz and Radcliffe 1917; Wang 1974),
which uncoil upon ovipo-sition (Ryder 1883; Hildebrand 1922).
Filaments are usually from five (Mid-daugh 1981) to eight (Ryder 1883) times the egg diameter in length.
Eggs may also adhere to each other in clusters (Hildebrand 1922; Leim and Scott 1966).
Incubation time for Atlantic sil-verside eggs was 3 days at 30*C (860 F),
5 days at 25*C (77*F),
10 days at 200C (68°F),
15 days at 18'C (64°F),
and 27 days at 15'C (59"F)
(Costello et al.
.1957; Austin et al.
1975).
An equation for predicting incubation time from water temperature, calculated from data in Austin et al.
(1975) by Martin and Drewry.(1978),
is:
log(t) = 2.2672
- 0.0623(T) where t = time in days and T = incu-bation temperature in degrees C.
Middaugh (1981) found that maxi-mum egg abundance in South Carolina waters occurred at depths of 1.6 to 2.2 m (5.3 to 7.2 ft) below the mean low water (low tide) line.
Embryo viability was also highest in this depth
- range, though a
statistically significant correlation between embryo viability and depth of embryo location was not indicated.
Yolk-Sac Larvae Atlantic silverside yolk-sac larvae range from 3.8 to 5.0 mm total length (TL) at hatching (Wang 1974).
The proportion of the original yolk-sac remaining at hatching depends on incubation temperature; a
defined yolk-sac is absent when eggs are incubated at 250 C (770 F) or less (Bayliff 1950; Austin et al.
1975).
Remaining yolk is absorbed 2
(Mid-daugh and Lempesis 1976) to 5 (Rubi-noff 1958) days after hatching.
Yolk-sac larvae are transparent with pigmented eyes at hatching (Hildebrand 1922; Middaugh and Lempesis 1976).
Middaugh (1981) found that larval hatching occurred primarily at night during high tides, and suggested that decreased predation may be a benefit of nocturnal emergence.
Larvae Atlantic silverside larvae range from 5.5 to 15.0 mm TL (Wang 1974).
Both yolk-sac larvae, and larvae have a notably forward anus, rarely far-ther behind the snout than one-fourth of the total larval length (Martin and Drewry 1978).
Size at transformation to the juvenile stage is not estab-
- lished, but transformation occurs before 20 mm TL (Wang 1974) and is complete when the anus has migrated back along the ventral surface of the body to the approximate midpoint (Hildebrand 1922).
An unusual method of sex deter-mination during the larval stage of Atlantic silversides was demonstrated in a series of laboratory experiments by Conover and Kynard (1981).
Lar-vae subjected to a "cold fluctuating" temperature regime similar to tempera-tures experienced by larvae in May, between 110 and 191C (52' and 66*F),
produced more females than males.
. In
- contrast, a
"warm fluctuating" 6
temperature regime similar to tempera-tures experienced by larvae in July, between 170 and 250C (630 and 77 0 F),
produced significantly more males than females.
- Further, it was determined that the mechanism of sex determina-tion was not by selective egg or larval mortality, but rather the temperature regime experienced by larvae during a critical period, which was between 32 and 46 days after hatching. The water temperature regime experienced by larvae at that stage of development determined whether mostly males or females developed (Conover and Kynard 1981).
These laboratory find-ings were corroborated by examination of sex ratios in natural populations (Essex
- Bay, Massachusetts) over time (Conover 1982).
Dovel (1971) reported that Atlan-tic silverside larvae were present throughout low salinity areas of upper Chesapeake
- Bay, from April through December.
Larvae were most abundant in surface waters
(<
3 m,
< 10 ft) and at salinities of 8 or 9 ppt.
Some lar-vae were found in waters where salin-ities ranged from 1
to 14 ppt and water temperatures from 12' to 300C (540 to 86%F).
In the Mystic River
- Estuary, Connecticut, Atlantic silver-side larvae were found primarily in upper estuarine zones and
- marshes, where the salinity profile ranged from 2 ppt at the surface to 14 ppt at 2 m
(6 ft) depth.
All larvae were collected in May and June and ranged from 5.2 to 7.5 mm TL (Pearcy and Richards.
1962).
Juveniles/Adults Juvenile Atlantic silversides range in size from about 20 mm TL (Wang 1974)
- to approximately 91 mm TL (males) or-98 mm TL (females)
(Leim and Scott 1966; Conover and Ross 1982).
The juvenile stage lasts from the completion of anal vent migration along the ventral midline (Martin and Drewry 1978) to cessation of growth in late fall (Conover 1982).
Smaller juveniles select habitats over vegetated substrates more often than the sand and gravel substrates selected by larger juveniles and adults (Briggs and O'Conner 1971).
Juvenile and adult Atlantic sil-versides inhabit intertidal
- creeks, marshes, and shore zones of bays and estuaries in spring, summer, and fall (Hildebrand and Schroeder 1928; Bigelow and Schroeder 1953).
Tempo-ral variation in local abundance, probably due in part to fish move-ments in relation to tidal patterns, has been reported (Merriman 1947; Shenker and Dean 1979; Conover 1982; Conover and Ross 1982).
Dur-ing spring, summer, and fall, Atlantic silversides have often been
- reported, as the most abundant species in marsh and estuarine habitats (Pearcy and Richards 1962; Mulkana 1966; Richards and Castagna 1970; Briggs 1975; Anderson et al.
1977),
yet they may be entirely absent from the same areas during winter (Bayliff 1950; Hoff and Ibara 1977; Conover 1982; Conover and Ross 1982).
Geographic variability exists.with the winter ecology and habitat of adult Atlantic silversides (Conover and. Murawski 1982).
In populations from Chesapeake Bay northward, Atlantic silversides are rare or absent from shore zones or shallow waters in midwinter (Bayliff 1950; Hoff and Ibara 1977; Conover and Ross 1982).
Richards and Castagna -
(1970) reported that adult Atlantic silversides were captured in midwinter with bot-tom trawls in deepwater areas of Chesapeake Bay and estuarine chan-nels along eastern Virginia.
Winter catches of adults out to 15 km (913 mi)
(Clark et al.
1969; Fahay 1975) and 170 km (105.6 mi)
(Conover and Murawski 1982) offshore have been reported.
In South Carolina tidal
- creeks, however, adults were present in high abundance throughout winter (Cain and Dean 1976; Shenker and Dean 1979).
7
National Marine Fisheries Service (NMFS) survey
- data, collected with bottom trawls from Cape Cod, Massa-
- chusetts, to Cape
- Hatteras, North
- Carolina, was summarized by Conover and Murawski (1982).
From 1972 to 1979 (data pooled),
percent frequency of occurrence (number of stations captured divided by number of sta-tions surveyed) of Atlantic silversides in depth strata, between 5 and 27 m (16 and 89 ft),
peaked in January (34.3%).
Atlantic silversides also occurred in March (21.4%),
April (9.6'o),
and November (4.9%).
Depth strata from 5 to 27 m were not sam-pled in February.
At depth strata between 27 and 366 m (89 and 1,200 ft)
(1963 to 1979, data pooled),
per-cent frequency of occurrence peaked in F'ebruary (11.2%),
and dropped off in March (4.3%) and April (1.5%).
The majority (86%)
of all Atlantic silver-sides captured in the' NMFS surveys were at depths less than 50 m (164 ft) and water temperatures between 2' and 60 C (360 and 430F) (Conover and Murawski 1982).
Comparison of winter catch rates during different times of the day indicated that overwintering Atlantic silversides may migrate vertically in the water column during twilight peri-ods.
Consistently higher numbers of silversides were captured during the day with bottom trawls than at night in the same overwintering areas (Con-over and Murawski 1982).
Biochemical characteristics (through electrophoresis) of Atlantic silverside stocks (Morgan and Ulanow-icz 1976) and the genus Menidia (Johnson 1975) have been described.
The applicability of such information for separation of stocks and apparent subspecies of Menidia menidia (M.
m.
- menidia, southern subspecies, and M.
- m.
- notata, northern subspecies) is discussed in Morgan and Ulanowicz (1976).
GROWTH CHARACTERISTICS Growth of young-of-the-year Atlantic silversides from hatching to mid-autumn was 10-15 mm/month in Long Island Sound (Austin et al.
1973),
7-14 mm/month in a
Rhode Island estuary (Mulkana 1966),
and 20 mm/month in Essex
- Bay, Massachu-setts (Conover and Ross 1982).
Young-of-the-year males attained 91.5 mm and 3.9 g by November in Essex Bay,, and females attained 98.0 mm and 4.8 g (Conover and Ross 1982).
Growth of Atlantic silversides virtually ceases between November and March, at least in areas where winter offshore migrations occur (Bayliff 1950; Bigelow and Schroeder 1953; Conover 1982; Conover and Ross 1982).
Condition factor of young-of-the-year Atlantic silversides in Essex
- Bay, Massachusetts, dropped signifi-cantly. between September and Novem-ber for the large 1976 year class, but not for the less abundant. 1977 year class (Conover and Ross 1982).
For both year classes, the condition factor r-mained stable through winter, increasing in April and May of the following spring.
Conover and Ross (1982) suggested that the 1976 year class may haVe exceeded the carrying capacity of the Essex Bay nursery
- area, resulting in the observed reduction in condition during late stages of the growing season (October and November).
G rowth rates of age 11 male Atlantic silversides in Essex Bay averaged 5.8 mm/month and 1.1 g/month over the period 6 May to 5 November. Females grew 5.5 mm/month and 1.4 g/month over the same period.
By 5 November, mean lengths and weights of female Atlantic silver-sides exceeded values for males by 10 mm and 2.9 g
(Conover and Ross 1982).
8
THE FISHERY Commercial and. Recreational Fisheries Commercial or recreational fisher-ies *for Atlantic, silversides are not documented.
The authors have observed a small and scattered com-mercial bait fishery for Atlantic sil-versides using minnow traps or small seines.
Such localized bait fisheries probably have little if any impact on Atlantic silverside populations.
Population Dynamics In general, the Atlantic silverside is a short-lived species.
Two-year-old fish have been reported (Bayliff 1950; Conover and Ross 1982),
but the majority of estuarine populations of Atlantic silversides in
- spring, sum-
- mer, and fall are juveniles (age 0+)
and age 1
adults (Conover and Murawski 1982).
Abundance of the 1977 year class of silverside juveniles in Essex
- Bay, Massachusetts, in late October and early November (data pooled) was
.ý (95 fi-estimated at 1.88 1.16/m (95 conf-dence limits).
Mean biomass of juve-niles peaked in late October and early November at 7.8 +/- 2.8 9/m 2 Adult densities on spawning grounds the next spring (1978) were estimated at 0.009 +/- 0:002/m2
, indicating a
total overwintering mortality rate of 99%
(Conover and Ross 1982).
Conover and Ross (1982) examined Atlantic sil-
- verside mortality estimates from other coastal areas of Massachusetts and found that overwintering mortality averaged 97%0 north of Cape Cod and 88% south and west of Cape Cod. Sim-ilarly high overwintering mortality was reported by Warfel and Merriman (1944) in Connecticut, Bayliff (1950) in Chesapeake Bay, and Austin et al.
(1973) in New York.
Conover and Ross (1982) also found that overwintering mortality of Atlantic silversides was selective against larger fish, and total mortality was negatively related to mean size and condition of the juvenile year class prior to winter migration.
They suggested
- that, since densities of adults returning the following spring were similar regardless of the fall population
- size, a
density compensa-tory mechanism of overwintering mor-tality may occur in Atlantic silverside populations.
Conover (1982) demonstrated that sex ratios of Atlantic silversides in Essex
- Bay, Massachusetts, fluctuated seasonally, partly because of the unusual mechanism of sex determina-tion described for this species (Con-over and Kynard 1981)
(see LIFE
,HISTORY-- Larvae section).
Sex rat-ios in July and August consistently favored
- females, while sex ratios in September (year-class recruitment complete),
- October, and November favored males.
Sex.
ratios on the spawning grounds the following spring either favored, females (1978) or were not significantly different from 1:1 (1976, 1977).
ECOLOGICAL ROLE Food Habits/Feeding Behavior Information about larval food
- habits, feeding
- behavior, and daily ration is not available.
Juvenile and adult Atlantic silversides are oppor-tunistic omnivores.
Food items con-sumed include
- copepods, mysids, amphipods, cladocerans, fish
- eggs, squid,
- worms, molluscan
- larvae, insects,
- algae, diatoms, and detritus (Bigelow and Schroeder 1953; Leim and Scott 1966; Thomson et al.
1971).
Atlantic silversides feed. in large
- schools, often following the tidal ebb and flow along feeding areas.
Common feeding areas include gravel and sand 9
- bars, open
- beaches, tidal
- creeks, river mouths and flooded zones of marsh vegetation (Bayliff 1950; Bige-low and Schroeder 1953).
Information about feeding periodicity is not avail-able.
In laboratory tests, unfed larvae and larvae fed for the first time on day 4 all died by day 6.
Survival of larvae fed at the end of day 2 varied with salinity.
At 20 ppt, all larvae were dead by day 8, while at 30 ppt, 40' survived through day 14 (Mid-duagh and Lempesis 1976).
Predators Atlantic silversides are important forage for such gamefish as striped
- bass, Atlantic mackerel, and bluefish.
(Bayliff 1950; Bigelow and Schroeder 1953; Schaefer 1970).
Other fish
- species, egrets, terns, gulls, cormo-
- rants, and blue crabs (Callinectes sapidus) also prey on spawning schools of Atlantic silversides (Mid-daugh 1981).. Blue crabs, ruddy turn-stones (Arenaria interpres morinella),
semipalmated sandpipers (Ereunetes pusillus),
and in particular, mummi-chogs (Fundulus heteroclitus),
may prey on eggs and larvae of Atlantic silversides (Middaugh 1981; Conover 1982).
Competitors Definitive studies of competitive interactions between Atlantic silver-sides and other species are lacking.
Some competition with the closely related inland silverside (Menidia beryllina) may occur, although these two atherinids appear to be spatially separated in many areas. The Atlantic silverside generally selects habitats more seaward than those of the inland silverside (Robbins 1969).
Role as Estuarine Biomass Exporter silversides migrate to offshore waters during late fall.
Numbers of age I
adults returning the following spring indicated very high overwintering mortality (99%).
Few if any age I fish make it to age 2; most age 1 fish die after spawning or during their second winter of life.
This essentially annual life
- cycle, with high mortality off-
- shore, suggests that Atlantic silver-sides are important exporters of sec-ondary production and biomass from marsh and estuarine systems to off-shore areas (Conover and Murawski 1982).
ENVIRONMENTAL REQUIREMENTS Temperature Eggs of Atlantic silverside toler-ated water temperatures as low as 15' C
(590 F),
but larvae that hatched died within 24 hr unless warmer water was located (Austin et al.
1975).
Temperatures as high as 30'C (860F) were also tolerated by eggs.
Visible yolk was present upon hatching in 20%
of the larvae reared at 30'C, but was absent in larvae hatched at 25'C (770 F) or less (Austin et al.
1975).
Optimum temperatures for hatching of
- eggs have not been determined.
Thermal shock of an 8'C (14'F) increase produced no mortality of Atlantic silverside larvae reared at 170 and 20'C (63' and 68°F),
19' mortal-ity at 25'C (77'F),
and 11% mortality at 30'C (86'F)
Thermal shock of a 14' C
(25' F) increase produced. 3%
mortality of larvae reared at 17'C (630 F),
0% at 20-C (680F),
and 1009% at256 and 300 C (770 and 86' F)
(Austin et al.
1975).
Austin et al.
(1975) con-cluded that, since Atlantic silverside larvae would be present in Long Island Sound at seasonal temperatures between 15' and 20'C (59' and 68'F),
the larval population would experience minimal stress from nuclear power-plant development on Long Island.
Conover and Murawski (1982) demonstrated that age 0*
Atlantic 10
Juvenile Atlantic silversides tol-erated water temperatures between 3T and 31'C (370 and880F),and preferred a
temperature range of 18' "to 250 C (640 to 77°F) in upper Chesapeake Bay, during summer and fall (Dovel 1971).
Juveniles and adults accli-mated to 6VC (43'F) and 8'C (46'F),
- however, preferred water tempera-tures of 150C (59' F)
(Meldrim and Gift 1971).
In
- general, avoidance behavior of juveniles and adults was observed when test temperatures were 110 to 14°C (200 to 25'F) higher than the acclimation temperature' (Meldrim and Gift 1971).
Pearce (1969) reported an upper lethal temperature of 32.00C (900 F) for Atlantic silversides col-lected from the Cape Cod Canal, Mas-sachusetts.
Critical thermal maxima (defined as the temperature at which opercular movements ceased for 30 seconds) for Atlantic silversides col-lected from the Patuxent
- River, Maryland, were 30.5'C (87 0 F) and 33.80C (93'F) for acclimation tempera-tures of 50C (41'F) and 15'C (599F),
respectively (Hall et al.
1982).
Atlantic silversides exposed to three different fluctuating temperature
- regimes, between 5 'C and 15 0 C, exhibited critical thermal maxima intermediate to the above values (Hall et al.
1982).
Lower and upper 48-hr median tolerance limits (TLM, the temperature at which 50%0 of test fish died by 48 hr) were determined by Hoff and Westman (1966) for a range of acclimation temperatures.
The lower TLM values for acclimation temperatures of 70, 14", 21', and 280 C (450,
- 570, 700, and 82°F)were 1.5' 20, 50, and 9.5'C (35', 36",
41',
-aod 49'F), respectively.
Upper TLM values for the same four acclimation temperatures were 220, 260, 300, and 320C (720,
- 790, 860, and 90'F),
respectively (Hoff and Westman 1966).
Salinity In laborat6ry tests, hatching was delayed 18 hr at 20 ppt salinity and 42 hr at 10 ppt, compared to hatching time at 30 ppt (incubation temperature was 21.1 0C or 70 0 F).
Percentage hatch was also reduced at salinities below 30 ppt, and optimum salinity for hatching was 30 ppt. Survival of lar-vae through 14 days was approxi-mately 77%0 at 30 ppt compared to only 23% at 20 ppt. Growth rate of larvae through day 14 was lower at 20 ppt compared to 30 ppt (Middaugh and Lempesis 1976).
Juvenile and adult Atlantic silversides tolerated salinities from freshwater (Tagatz and Dudley 1961; Tagatz 1967) to 37.8 ppt (Tagatz and Dudley 1961).
Juveniles were captured from upper Chesapeake Bay in salinities from 1 to 14 ppt, but preferred 7 to 8 ppt (Dovel 1971).
11
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M.S.
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109 pp.
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0., and B.
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Kynard.
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1971.
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71 pp.
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An annotated list of larval and juvenile fishes cap-tured with surface-towed meter nets in the South Atlantic Bight during four RV Dolphin cruises between May, 1967 and February, 1973.
NOAA Tech.
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A.
1948. Speciation in the fishes of the genus Menidia.
Evo-lution 2: 306-313.
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W., Jr.,
D.
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Abell.
1982.
Thermal response of Atlantic silversides (Menidia menidia) acclimated to constant and asymmetric fluctuat-ing temperatures.
Arch.
Hydro-biol. 94: 318-325.
Hildebrand, S.
F.
1922.
Notes on habits and development of eggs and larvae of the silversides, Menidia menidia and M. beryllina.
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N.
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Abundance, diversity, and stability in shore-zone fish communities in an area of Long Island Sound affected by the thermal discharge of a
nuclear power station.
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G., and R.
M.
Ibara.
1977.
Factors affecting the seasonal abundance, composition and di-versity of fishes in a southeastern New England estuary.
Estuarine Coastal Mar. Sci. 5: 665-678.
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G., and J.
R.
Westman.
1966.
The temperature tolerances of three species of marine fishes.
J. Mar. Res. 24(2): 131-139.
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E.
1978.
Reproductive strategies of coastal marine fishes in the tropics.
Environ.
Biol.
Fishes 3: 65-84.
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1975.
Biochemical sys-tematics of the Atherinid genus Menidia.
Copeia 1975: 662-691.
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C.
1902.
Notes on the silversides of the genus Menidia of the east coast of the United
- States, with descriptions of two new subspecies.
Rep.
U.
S.
Fish.
Comm. (1901): 241-267.
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and L.
Radcliffe.
1917.
Notes on the embryology and lar-val development of twelve teleos-tean fishes.
U.
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Fish.
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H.,
and W.
B.
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Fishes of the Atlantic coast of Canada.
Fish.
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155: 1-485.
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D.,
and G.
E.
Drewry.
1978.
Development of fishes of the mid-Atlantic
- Bight, Volume VI.
U.
S.
Fish Wildl.
Serv. Biol.
Serv.
Program FWS/OBS-78/12.
416 pp.
- Massmann, W.
H.
1954.
Marine fishes in fresh and brackish waters of Virginia rivers.
Ecology 35:
75-78.
- Meldrim, J.
W.,
and J.
J' Gift.
1971.
Temperature preference, avoid-ance and shock experiments with estuarine fishes. Ichthyol. Assoc.
Bull.
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75 pp.
- Merriman, D.
1941.
Studies on striped bass of the Atlantic coast. U.
S.
Fish Wildl. Serv. Fish.
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13
- Merriman, D.
1947.
Notes on the midsummer ichthyofauna of a
Connecticut beach at different tide levels. Copeia 1947: 281-286.
- Middaugh, D.
P.
1981.
Reproductive ecology and spawning periodicity of the Atlantic silverside. Copeia 1981: 766-776.
- Middaugh, D.
P.,
and P.
W. Lempe-sis.
1976.
Laboratory spawning and rearing of a marine fish, the silverside Menidia menidia meni-dia. Mar.
Biol. 35: 295-300.
- Middaugh, D.
P.,
G.
I. Scott, and J.
M.
Dean.
1981.
Reproductive behavior of the Atlantic silver-side.
Environ.
Biol.
Fishes 6:
269-276.
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P.,
II, and N.
I. Ulanow-icz. 1976.
The frequency of mus-cle protein polymorphism in Meni-dia menidia along the Atlantic coast. Copeia 1976: 356-360.
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The growth and feeding habits of juvenile fishes in two Rhode Island estuaries.
Gulf Res.
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1958. Raising the Atheri-nid fish, Menidia menidia, in the laboratory. Copeia 1958: 146-147.
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2448:
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15
50272-101 REPORT DOCUMENTATION REPORT NO.
2.
PAGE FWS/OBS-82/1.10*
- 4. Title and Subtitle Species Profiles:
Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Mid-Atlantic)
-- Atlantic Silverside
- 7. Author(s)
Clemon W. Fay, Richard J. Neves, Garland B. Pardue
- 9. Performing Organization Name and Address Department of Fisheries and Wildlife Sciences Virginia Polytechnic Institute and State University Blacksburg, VA 24061
- 3. Recpient's Accession No.
- 5. Reort ite 98 6ao,*tober 1983 6.
S. Pedor--ing Organizationi Riept. N10.
- 10. Project/T..si/Work Unit No.
- 11. Contract(C) or Grant(G) No.
(C)
(G) 1Z. Sponsoring Organization Name and Address
- 13. Type of Report & Period Covered National Coastal Ecosystems Team U.S. Army Corps of Engineers Fish and Wildlife Service Waterways Experiment Station U.S. Department of the Interior P.O. Box 631 14.
Washington, DC 20240 Vicksburg, MS 39180
- 15. Supplementary Notes
- U.S.
Army Corps of Engineers report No.
TR EL-82-4
. 16. Abstract (Limit: 200 -ords)
Species profiles are literature summaries of the taxonomy, morphology, range, life history, and environmental requirements of coastal aquatic species.
They are prepared to assist in environmental impact assessment.
The Atlantic silverside (Menidia menidia) is an important link in estuarine food webs as an opportunistic omnivore and as forage for large piscivores such as striped bass (Morone saxatilis) and bluefish (Pomatomus saltatrix).
Many times the Atlantic silverside is the most abundant fish species encountered in estuaries and tribu-taries.
They mature at age I and spawn in the intertidal zone of estuaries from March to June in the mid-Atlantic region.
Few 2-year-old fish are ever encountered, so the Atlantic silverside is basically a short-lived species.
Most spawning occurs at high tide during new or full moon phases.
Eggs are adhesive and are found attached to submerged vegetation.
Larvae, juveniles, and adults generally inhabit similar areas.
Sex is determined in larval development 32 to 46 days after hatching, and is a function of parental genotype and water temperature regime during the critical period.
Fisheries for this species are not documen-ted.
Eggs can tolerate water temperatures between 15' and 30'C, and larvae need temperature above 150C for survival.
Larvae tolerate relatively acute temperature increases.
Upper lethal temperatures for juveniles and adults range from 30.50 to 33.8 0C, depending on acclimation temperature.
Salinities of 20 ppt or lower significantly delay hatching and affect larval survival.
Juveniles and adults tolerate the full range of naturally occurring salinities (i.e., freshwater to at least 37.8 ppt).
- 17. Document Analysis
- a. Descriptors Estuaries Fishes Growth Feeding
- b. Identifiers/Open.Ended Terms Atlantic silverside Menidia menidia Salinity requirements Temperature requirements Life history Spawning
- c. COSATI Field/Group
- 18. Availability Statement Unl imited
- 19. Security Class (This Report)
- 21. No. of Pages Unclassified 15
- 20. Security Class (This Page)
- 22. Price t n c lfl gch i f ip2 r
, ee 51-9.18)
OPTIONAL FORM 27Z (4-77)
(Formerly NTIS-35)
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REGION I Regional Director U.S. Fish and Wildlife Service Lloyd Five Hundred Building, Suite 1692 500 N.E. Multnomah Street Portland, Oregon 97232 REGION 4 Regional Director U.S. Fish and Wildlife Service Richard B. Russell Building 75 Spring Street, S.W.
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