ML17309A733

Annual Environ Operating Rept 1993, Vols 1 & 2.W/940426 Ltr

ML17309A733
Person / Time
Site:	Saint Lucie
Issue date:	12/31/1993
From:	Sager D FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
AB-631, L-94-110, NUDOCS 9405040192
Download: ML17309A733 (161)

Text

ACCELERATED DISTMBUTION DEMONST$&TION SYSTEM 0 ', ~

REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

DOCKET FACIL:50-389 St. Lucie Plant, Unit 2, Florida Power 6 Light Co. 05000389

,AUTH;NAME AUTHOR AFFILIATION SAGER,D.A. Florida Power & Light Co.

RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

"St Lucie 6 2 426 t r. Annual 2 Environ Operating Rept 1993," Vols 1 D

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NOTE TO ALL "RIDS" RECIPIENTS PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LINIS FOR DOCUMENTS YOU DON'T NEED!

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0 P.O. Box 128, Ft. Pierce, FL 34954-0128 April 26, 1994 L-94-110 10 CFR 50.4 10 CFR 50.36 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555

'e: St. Lucie Unit Docket Nos. 50-389 2

1993 Annual Environmental 0 eratin Re ort-In accordance with Section 5.4.1 of the St. Lucie Unit 2 Environmental Protection Plan (EPP), enclosed is the Annual Environmental Operating Report for 1993.

Should there be any questions on this information, please contact us ~

Very truly yours, D. A. ager Vice esident St. Lucie Plant DAS/CDW/kw cc: Stewart D. Ebneter, Regional Administrator, Region Senior Resident Inspector, USNRC, St. Lucie Plant II, USNRC Attachment DAS/PSL 81108-94 Qg ~8 940S040192 93123i PDR ADOCK 05000389 J'DR, ~

an FPL Group company

I 1 94PGPgoy9P FLORIDA POWER 8c LIGHT COMPANY ST. LUCIE UNIT 2 ANNUALENVIRONMENTAL OPERATING REPORT 1993 VOLUME 1 APRIL 1994 FLORIDA POWER & LIGHT COMPANY JUNO BEACH, FLORIDA APPLIED BIOLOGY, INC.

DECATUR, GEORGIA

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ENVIRONMENTALOPERATING REPORT TABLE OF CONTENTS TABLE OF CONVERSION FACTORS FOR METRIC UNITS EXECUTIVE

SUMMARY

Introduction Turtle Nesting Survey Intake Canal Monitoring INTRODUCTION

Background

Area Description Plant Description TURTLES Introduction Materials and Methods 10 Nesting Survey .. 10 Intake Canal Monitoring Studies to Evaluate and/or Mitigate Intake Entrapment . 15 Results and Discussion 15 Nesting Survey 15 Spatial Distribution of Loggerhead Turtle Nests .... 15 Long-Term Trends in Loggerhead Turtle Nesting 18 Seasonal Patterns of Loggerhead Turtle Nesting 19 Predation on Loggerhead Turtle Nests 20 Green and Leatherback Turtle Nesting, 21 Intake Canal Monitoring ~ ~ 23 Relative Abundance and Temporal Distribution 23 Size-Class Distributions 25 Sex Ratios 28 Capture Efficiencie 29 Relative Condition 31 Mortalities 33 Recapture Incidents 34 Summary 35 UTERATURE CITED ... 39 FIGURES 47 TABLES

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TABLE OF CONVERSION FACTORS FOR METRIC UNITS To convert Multi I b To obtain centigrade (degrees) ( C x 1.8) + 32 fahrenheit (degrees) centigrade (degrees) C + 273.18 kelvin (degrees) centimeters (cm) 3.937 x 10 inches centimeters (cm) 3.281 x10 feet centimeters/second (cm/sec) 3.281 x 10 feet per second cubic centimeters (cm ) 1.0 x 10 liters grams (g) 2.205 x 10 pounds grams (g) 3.527 x 10 ounces (avoirdupois) hectares (ha) 2.471 acres kilograms (kg) 1.0 x10 grams kilograms (kg) 2.2046 pounds kilograms (kg) 3.5274 x 10 ounces (avoirdupois) kilometers (km) 6.214 x 10 miles (statute) kilometers (km) 1.0 x 10 millimeters liters (I) 1.0 x 10 cubic centimeters (cd) liters (I) 2.642 x 10 gallons (US liquid) meters (m) 3.281 feet meters (m) 3.937 x 10 inches meters (m) 1.094 yards milligrams (mg) 1.0 x10 grams milligrams/liters (mg/I) 1.0 parts per million milliliters (ml) 1.0 x 10 liters (US liquid) millimeters (mm) 3.937 x 10 inches millimeters (mm) 3.281 x 10 feet square centimeters (cm ) 1.550 x 10 square inches square meters (m ) 1.076 x 10 square feet square millimeters (mm ) 1.55 x 10 square inches

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EXECUTIVE

SUMMARY

INTRODUCTION The St. Lucie Plant is an electric generating station on Hutchinson Island in St.

Lucie County, Florida. The plant consists of two nuclear-fueled 850-MW units; Unit 1 was placed on-line in March 1976 and Unit 2 in May 1983. This document has been prepared to satisfy the requirements contained in the United States Nuclear Regulatory Commission's Appendix B Environmental Protection Plan (EPP) to St. Lucie Unit 2 Facility Operating License No. NPF-16. This report discusses environmental protection activities related to sea turtles as required by Subsection 4.2 of the EPP. Other routine annual reporting requirements are addressed in Volume 2, also entitled "St. Lucie Unit 2 Annual Environmental Operating Report".

TURTLE NESTING SURVEY Since monitoring began in 1971, there have been considerable year-to-year fluc-tuations in sea turtle nesting activity on Hutchinson Island. However, data collected through 1993 have shown no long-term reductions in nesting on the island. Relatively high nesting during recent years may actually reflect an increase in the number of nest-ing females in the study area. On a smaller scale, power plant operation has had no significant effect on nesting near the plant. Low nesting activity in 1975 and again in 1981 -1983 in the vicinity of the plant was attributed to nighttime construction activities associated with installation of plant intake and discharge structures. Nesting returned to normal or above normal levels following both periods of construction. During 1991,

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daytime construction activities associated with velocity cap repairs had no apparent ef-fect on nesting. Formal requirements to conduct nesting surveys expired in 1986 but this program was voluntarily continued through 1993 with agreement from federal and state agencies.

INTAKE CANAL MONITORING Since plant operation began in 1976, 2,838 sea turtles (including 150 recaptures) representing five different species have been removed from the intake canal. Seventy-nine percent of these were loggerheads. Differences in the numbers of turtles found during different months and years have been attributed primarily to natural variation in the occurrences of turtles in the vicinity of the plant, rather than to operational influen-ces of the plant itself. The majority of turtles removed from the intake canal (about 94 percent) were captured alive and released back into the ocean. Ongoing evaluations and improvements to the canal capture program have substantially reduced mortalities of entrapped sea turtles during. recent years. Turtles confined between the A1A barrier net and intake headwalls typically reside in the canal for a relatively short period prior to capture, and most are in good to excellent condition when caught.

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INTRODUCTION BACKGROUND This document has been prepared to satisfy the requirements contained in the United States Nuclear Regulatory Commission's (NRC) Appendix B Environmental Protection Plan to St. Lucie Unit 2 Facility Operating License No. NPF-16.

In 1970, Florida Power & Light Company (FPL) was issued Permit No. CPPR-74 by the United States Atomic Energy Commission, now the Nuclear Regulatory Com-mission, that allowed construction of Unit 1 of the St. Lucie Plant, an 850-MW nuclear-powered electric generating station on Hutchinson Island in St. Lucie County, Florida.

St Lucie Plant Unit 1 was placed on-line in March 1976. In May 1977, FPL was issued Permit No.'CPPR-144 by the NRC for the construction of a second 850-MW nuclear-powered unit. Unit 2 was placed on-line in May 1983 and began commercial operation in August of that year.

St. Lucie Plant Units 1 and 2 use the Atlantic Ocean as a source of water for once-through condenser cooling. Since 1971, the potential environmental effects resulting from the intake and discharge of this water have been the subject of FPL-sponsored biotic studies at the site.

Baseline environmental studies of the marine environment adjacent to the St. Lucie Plant were described in a series of reports published by the Florida Department of Natural Resources (Camp et al., 1977; Futch and Dwinell, 1977; Gallagher, 1977; Gal-lagher and Hollinger, 1977; Worth and Hollinger, 1977; Moffler and Van Breedveld,

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1979; Tester and Steidinger, 1979; Walker, 1979; Walker et al., 1979; Walker and Steidinger, 1979; Lyons, 1989). The results of Unit 1 operational and Unit 2 preopera-tional biotic monitoring at the St. Lucie Plant were presented in six annual reports (ABI, 1977, 1978, 1979, 1980a, 1981b, 1982). In January1982, a National Pollutant Discharge Elimination System (NPDES) permit was issued to FPL by the US Environmental Protec-tion Agency (EPA). The EPA guidelines for the St. Lucie site biological studies were based on the document entitled "Proposed St. Lucie Plant Preoperational and Opera-tional Biological Monitoring Program - August 1981" (ABI, 1981c). Findings from these studies were reported in three annual reports (ABI, 1983, 1984a, 1985a). The EPA biotic monitoring requirements were deleted from the NPDES permit in 1985.

Jurisdiction for sea turtle studies is with the NRC, which is considered to be the lead federal agency relative to consultation under the Endangered Species Act.

Previous results dealing exclusively with sea turtle studies are contained in ten annual environmental operating reports covering the period from 1983 through 1992 (ABI 1984b, 1985b, 1986, 1987,'1988, 1989, 1990,'1991, 1992, 1993). This report describes the 1993 environmental protection activities related to sea turtles, as required by Sub-section 4.2 of the St. Lucie Plant Unit 2 Environmental Protection Plan.

AREA DESCRIPTION The St. Lucie Plant is located on a 457-ha site on Hutchinson Island on Florida's east coast (Figures 1 and 2). The plant is approximately midway between the Ft. Pierce and St. Lucie Inlets. It is bounded on its east side by the Atlantic Ocean and on its west side by the Indian River Lagoon.

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Hutchinson Island is a barrier island that extends 36 km between inlets and ob-tains its maximum width of 2 km at the plant site. Elevations approach 5 m atop dunes bordering the beach and decrease to sea level in the mangrove swamps that are com-mon on much of the western side. Island vegetation is typical of southeastern Florida coastal areas; dense stands of Australian pine, palmetto, sea grape and Spanish bayonet are present at the higher elevations, and mangroves abound at the lower eleva-tions. Large stands of black mangroves, including some on the plant site, have been killed by flooding for mosquito control over past decades.

The Atlantic shoreline of Hutchinson Island is composed of sand and shell hash with intermittent rocky promontories protruding through the beach face along the southern end of the island. Submerged coquinoid rock formations parallel much of the island off the ocean beaches. The ocean bottom immediately offshore from the plant site consists primarily of sand and shell sediments. The unstable substrate limits the establishment of rooted macrophytes.

The Florida Current, which flows parallel to the continental shelf margin, begins to diverge from the coastline at West Palm Beach. At Hutchinson Island, the current is approximately 33 km offshore. Oceanic water associated with the western boundary of the current periodically meanders over the inner shelf, espe'cially during summer months.

PLANT DESCRIPTION The St. Lucie Plant consists of two 850-MW nuclear-fueled electric generating units that use nearshore ocean waters for the plant's once-through condenser cooling

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water system. Water for the plant enters through three submerged intake structures located about 365 m offshore (Figure 2). Each of the intake structures is equipped with a velocity cap to minimize fish entrainment. Horizontal intake velocities are less than 30 cm/sec. From the intake structures, the water passes through submerged pipes (two 3.7 m and one 4.9 min diameter) under the beach and dunes that lead to a1,500-rn long intake canal. This canal transports the water to the plant. After passing through the plant, the heated water is discharged into a 670-m long canal that leads to two buried discharge pipelines. These pass underneath the dunes and beach and along the ocean floor to the submerged discharges, the first of which is approximately 365 m offshore and 730 m north of the intake.

Heated water leaves the first discharge line from a Y-shaped nozzle (diffuser) at a design velocity of 396 cm/sec. This high-momentum jet entrains ambient water, result-ing in rapid heat dissipation. The ocean depth in the area of the first discharge is about 6 m. Heated water leaves the second discharge line through a series of 48 equally spaced high velocity jets along a 323-m manifold (multiport-diffuser). This diffuser starts 168 m beyond the first discharge and terminates 856 m from shore. The ocean depth along this diffuser is from about 10 to 12 m. As with the first diffuser, the purpose of the second diffuser is to entrain ambient water and rapidly dissipate heat. From the points of discharge at both diffusers, the warmer water rises to the surface and forms a surface plume of heated water. The plume then spreads out on the surface of the ocean under the influence of wind and currents and the heat dissipates to the at-mosphere.

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TURTLES The NRC's St. Lucie Unit 2 Appendix B Environmental Protection Plan issued April 1983 contains the following technical specifications:

4.2 Terrestrial A vatic Issues Issues on endangered or threatened sea turtles raised in the Unit 2 FES-OL [NRC, 1982] and in the Endangered Species Biological As-sessment (March 1982) [Bellmund et al., 1982] will be addressed by programs as follows:

Beach nesting surveys for all species of sea turtles will be conducted on a yearly basis for the period of 1982 through 1986. These sur-veys will be conducted during the nesting season from ap-proximately mid-April through August.

The Hutchinson Island beach will be divided into 36 one-km-long survey areas. In addition, the nine 1.25-km-long survey areas used in previous studies (1971-1979) will be maintained for comparison purposes. Survey areas will be marked with numbered wooden pla-ques and/or existing landmarks.

The entire beach will be surveyed seven days a week. All new nests and false crawls will be counted and recorded in each area. After counting, all crawl tracks will be obliterated to avoid recounting.

Predation on nests by raccoons or other predators willbe recorded as it occurs. Records will be kept of any seasonal changes in beach topography that may affect the suitability of the beach for nesting.

4.2.2 A program that employs light and/or sound to deter turtles from the intake structure will be conducted. The study will determine with laboratory and field experiments if sound and/or light will result in a reduction of total turtle entrapment rate.

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The study shall be implemented no later than after the final removal from the ocean of equipment and structures associated with con-struction of the third intake structure and the experiments shall ter-minate 18 months later. Four months after the conclusion of the experimental period, a report on the results of the study will be sub-mitted to NRC, EPA, National Marine Fisheries Service (NMFS), and the US Fish and Wildlife Service (USFWS) for their evaluation. If a statistically significant reduction in annual total turtle entrapment rate of 80 percent or greater can be demonstrated, using the developed technology and upon FPL receiving written concurrence by NRC, EPA, NMFS, and USFWS then permanent installation of the deterrent system shall be completed and functioning no later than 18 months after the agencies'oncurrence. The design of this study needs to take into account the significant annual variation in turtle entrapment observed in the past.

If an 80 percent reduction of turtle entrapment cannot be projected to all three intake structures, then an interagency task force com-posed of NRC, EPA, NMFS, USFWS, and FPL shall convene 18 months after completion of the third intake and determine if other courses of action to mitigate and/or reduce turtle entrapment are warranted (such as physical barrier, emergence of new technology or methods to deter turtles).

4.2.3 Alternative methods or procedures for the capture of sea,turtles entrapped in the intake canal will be evaluated. If a method or pro-cedure is considered feasible and cost effective and may reduce capture mortality rates, it will be field tested in the intake canal.

4.2.5 Ca ture and Release Pro ram Sea turtle removal from the intake canal will be conducted on a con-tinuing basis. The turtles will be captured with large mesh nets, or other suitable nondestructive device(s), if deemed appropriate. A formalized daily inspection, from the shoreline, of the capture device(s) will be made by a qualified individual when the device(s) are deployed. The turtles will be identified to species, measured, weighed (if appropriate), tagged and released back into the ocean.

Records of wounds, fresh or old, and a subjective judgement on the condition of the turtle (e.g., barnacle coverage, underweight) will be maintained. Methods of obtaining additional biological/physiologi-cal data, such as blood analyses and parasite loads, from captured

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sea turtles will be pursued. Dead sea turtles will be subjected to a gross necropsy, if found in fresh condition.

INTRODUCTION Hutchinson Island, Florida, is an important rookery for the loggerhead turtle, Caret-ta caretta and also supports some nesting of the green turtle, Chelonia ~mdas and th I th I kl hl,~dh I I Id td II 1,1999;9 .1999;9 I-lagher et al., 1972; Worth and Smith, 1976; Williams-Walls et al., 1983). Allthree species are protected by state and federal statutes. The federal government classified the log-gerhead turtle as a threatened species. The leatherback turtle and the Florida nesting population of the green turtle are listed by the federal government as endangered species. Because of reductions in world populations of marine turtles resulting from in-tentional harvest, incidental capture by various fisheries and loss of habitat due to coastal development (Magnuson et al., 1990), maintaining the vitality of the Hutchin-son Island rookery is important.

It has been a prime concern of FPL that the construction and subsequent opera-tion of the St. Lucie Plant would not adversely affect the Hutchinson Island rookery.

Because of this concern, FPL has sponsored monitoring of marine turtle nesting ac-tivity on the island since 1971.

Daytime surveys to quantify nesting, as well as nighttime turtle tagging programs, were conducted in odd numbered years from 1971 through 1979. During daytime nest-ing surveys, nine 1.25-km-long survey areas were monitored five days per week (Figure 3). The St. Lucie Plant began operation in 1976; therefore, the first three survey years (1971, 1973 and 1975) were preoperational. Though the power plant was not operat-

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ing during 1975, St. Lucie Plant Unit No. 1 ocean intake and discharge structures were installed during that year. Installation of these structures included nighttime construc-tion activities conducted offshore from and perpendicular to the beach. Construction had been completed and the plant was in. full operation during the 1977 and 1979 sur-veys.

A modified daytime nesting survey was conducted in 1980 during the preliminary construction of the ocean discharge structure for St. Lucie Plant Unit 2. During this study, four of the previously established 1.25-km-long survey areas were monitored.

Additionally, eggs from turtle nests potentially endangered by construction activities were relocated.

Every year from 1981 through 1993, 36 1-km-long survey areas comprising the entire island were monitored seven days a week during the nesting season (Figure 3).

Ttle St. Lucie Plant Unit 2 discharge structure was installed during the 1981 nesting

-season. Offshore and beach construction of the Unit,2 intake structure proceeded throughout the 1982 nesting season and was completed near the end of the 1983 season. Construction activities associated with installation of both structures were similar to those conducted when Unit 1 intake and discharge structures were installed.

Eggs from turtle nests potentially endangered by construction activities were relocated during all three years.

During 1991, another major offshore construction project was undertaken to replace damaged velocity caps on the three intake structures. A large elevated plat-form, from which repair activities were conducted, was erected around the three struc-

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tures. Construction occurred throughout the nesting season. However, in contrast to previous offshore projects, work was restricted almost entirely to daylight hours, nighttime lighting of the work area was minimal, and no equipment or materials were used on the beach. A sea turtle protection plan implemented in support of the project included caging of nests along a 1,500 m section of beach west of the platform and release of hatchlings to unaffected areas to the north and south. This plan was intended to mitigate any negative effects potentially resulting from required safety and naviga-tional lighting on and near the platform.

Requirement 4.2.1 of the NRC's St. Lucie Unit 2 Appendix B Environmental Protec-tion Plan was completed with submission of the 1986 nesting survey data (ABI, 1987).

The nesting survey was continued voluntarily through 1993 with agreement from federal and state agencies. Results are presented in this report and discussed in relation to previous findings.

In addition to monitoring sea turtle nesting activities and relocating nests away from plant construction areas, removal of turtles from the intake canal has been an in-tegral part of the St. Lucie Plant environmental monitoring program. Turtles entering the ocean intake structures are entrained with cooling water and rapidly transported through the intake pipes into an enclosed canal system where they must be manually captured and returned to the ocean. Since the plant became operational in 1976, turtles entrapped in the intake canal have been systematically captured, measured, weighed, tagged and released.

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Previous publications and technical reports have presented findings of the nest-ing surveys, nest relocation activities and canal capture program (Gallagher et al., 1972; Worth and Smith, 1976; ABI, 1978, 1980a, 1981a, 1982, 1983, 1984b, 1985b, 1986, 1987, 1988, 1989, 1990, 1991, 1992; Williams-Walls et al., 1983; Proffitt et al., 1986; Ernest et al., 1988, 1989; Martin et al., 1989a, 1989b; Wibbels et al., 1991). Results of studies to assess the effects of thermal discharges on hatchiing swimming speed have also been reported (ABI, 1978; O'ara, 1980). The purpose of this report is to 1) present 1993 sea turtle nesting survey data and summarize observed spatial and tem-poral nesting patterns since 1971, 2) document and summarize predation on turtle nests since 1971, and 3) present 1993 canal capture data and summarize comparable data collected since 1976.

MATERIALSAND METHODS

~Ni S Methodologies used during previous turtle nesting surveys on Hutchinson Island were described by Gallagher et al. (1972), Worth and Smith (1976) and ABI (1978, 1981a, 1982, 1987, 1988, 1989). Methods used during the 1993 survey were designed to allow comparisons with these previous studies.

On 12 and 14 April 1993, preliminary nest surveys were conducted along Hutchin-son Island from the Ft. Pierce Inlet south to the St. Lucie Inlet. From 16 April through 10 September, nest surveys were conducted on a daily basis. To confirm that nesting had ceased, additional surveys were conducted on 13 and 15 September. Biologists used small off-road motorcycles to survey the island each morning. New nests, non-10

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'esting emergences (false crawls), and nests destroyed by predators were recorded for each of the 36 1-km-long survey areas comprising the entire island (Figure 3). The nine 1.25-km-long survey areas established by Gallagher et al. (1972) also were monitored so comparisons could be made with previous studies.

During the daily nest monitoring, any major changes in topography that may have affected the beach's suitability for nesting were recorded. In addition, each of the 36 1-km-long survey areas has been systematically analyzed and categorized based on beach slope (steep, moderate, etc.), width from high tide line to the dune, presence of benches (areas of abrupt vertical relief) and miscellaneous characteristics (packed sand, scattered rock, vegetation on the beach; exposed roots on the primary dune, etc.).'n a cooperative effort, data from stranded turtles found during beach surveys were routinely provided to the Florida Department of Environmental Protection and the National Marine Fisheries Service (NMFS) through the Sea Turtle Stranding and Sal-vage Network.

Intake Canal Monitorin Most turtles entrapped in the St. Lucie Plant intake canal were removed by means of large-mesh tangle nets fished between the intake headwalls and a barrier net located at the Highway A1A bridge (Figure 2). Nets used during 1993 were from 30 to 40 m in length, 3 to 4 m deep and composed of 40 cm stretch mesh nylon twine. Large floats were attached to the surface, and unweighted lines used along the bottom. Turtles en-tangled in the nets generally remained at the water's surface until removed.

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Since its inception in 1976, ABI's canal capture program has been under continual review and refinement in an attempt to minimize both entrapment times and in-juries/mortalities to entrapped sea turtles. Prior to April 1990, turtle nets were usually deployed on Monday mornings and retrieved on Friday afternoons. During periods of deployment, the nets were inspected for captures by ABI personnel at least twice each day (mornings and afternoons). Additionally, St. Lucie Plant personnel checked the nets periodically, and ABI was notified immediately if a capture was observed. ABI's sea turtle specialists were on call 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> a day to retrieve captured turtles from the plant Beginning April 1990, after consultation with NMFS, net deployment was scaled back to daylight ho~rs only. Concurrently, surveillance of the intake canal was in-creased and ABI personnel remained on site for the duration of each day's netting ac-tivities. This measure decreased response time for removal of entangled turtles from nets and provided an opportunity to improve daily assessments of turtle levels within the canal. Records of daily canal observations were compared with capture data to as-sess capture efficiencies.

The A1A barrier net is used to confine turtles to the easternmost section of the in-take canal, where capture techniques have been most effective. This net is constructed of large diameter polypropylene rope and has a mesh size of 20.3 cm x 20.3 cm. A cable and series of large floats are used to keep the top of the net above the water' surface, and the bottom is anchored by a series of heavy blocks. The net is inclined at a slope of 3:1, with the bottom positioned upstream of the surface cable. This reduces 12

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bowing in the center and minimizes the risk of a weak or injured turtle being pinned un-derwater by strong currents.

In the past, the integrity of the barrier net was occasionally compromised, and turtles were able to move west of A1A. These turtles were further constrained downstream by an underwater intrusion detection system (UIDS) consisting, in part, of a large barrier positioned perpendicular to the north-south arm of the canal (Figure 2). The UIDS security barrier also consists of 20.3 cm x 20.3 cm mesh.

Prior to completion of the UIDS in December 1986, turtles uncontained by the A1A barrier net were usually removed from the canal at the intake wells of Units 1 and 2 (Figure 2). There they were retrieved by means of large mechanical rakes or specially designed nets. Following construction of the UIDS barrier, all but the smallest in-dividuals were unable to reach the intake wells. Thus, as required, tangle nets were also deployed west of A1A. Improvements made to the A1A barrier net during 1990 have effectively confined all turtles larger than 32.5 cm to the eastern end of the canal.

Formal daily inspections of the intake canal were made to determine the numbers, locations and species of turtles present. Surface observations were augmented with periodic underwater inspections using SCUBA, particularly in and around the A1A bar-rier net. Because of the reduction in total netting hours since April 1990, increased ef-fort has been directed toward hand capture of turtles. This effort, accomplished by diving and use of dip nets, has proved very effective during periods of good water clarity.

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Regardless of capture method, all turtles removed from the canal were identified to species, measured, weighed, tagged, and examined for overall condition (wounds, abnormalities, parasites, etc.). Healthy turtles were released into the ocean the same day of capture. Sick or injured turtles were treated and occasionally held for observa-tion prior to release. When treatment was warranted, injections of antibiotics and vitamins were administered by permitted veterinarians. Resuscitation techniques were used if a turtle was found that appeared to have died recently. Beginning in 1982, necropsies were conducted on dead turtles found in fresh condition; one necropsy was performed during 1993.

Since 1982, blood samples have been collected and analyzed to determine the sex of immature turtles. Blood was removed from the paired dorsal cervical sinuses of subject turtles using the technique described by Owens and Ruiz (1980). The sa'rnples were maintained on ice and later centrifuged for 15 minutes to separate cells and serum.

Sex determinations were subsequently made by researchers at Texas A 8 M Univer-sity using radioimmunoassay for serum testosterone (Owens et al., 1978).

Florida Power L Light Company and Applied Biology, Inc. continued to assist other sea turtle researchers in 1993. Since the program began, data, specimens and/or assistance have been given to the Florida Department of Environmental Protection, National Marine Fisheries Service, US Fish and Wildlife Service, US Army Corps of En-gineers, Smithsonian Institution, South Carolina Wildlife and Marine Resources Division, Center for Sea Turtle Research (University of Florida), Florida Atlantic Univer-sity, University of Central Florida, Texas A 8 M University, University of Rhode Island, University of South Carolina, University of Illinois, University of Georgia, Virginia Institute 14

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of Marine Science, Western Atlantic Turtle Symposium, South Atlantic Fishery Manage-ment Council, Florida Marine Fisheries Commission, Harbor Branch Oceanographic Institution and the National Research Council.

Studies to Evaluate and or Miti te Intake Entra ment A program that assessed the feasibility of using light and/or sound to deter turtles from entering the St. Lucie Plant intake structures was conducted in 1982 and 1983 and completed in January 1984. As required, test results and evaluations were written up and a presentation was made to the NRC, National Marine Fisheries Service and the Florida Department of Natural Resources on 11 April 1984. Requirement 4.2.2 of

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the NRC's St. Lucie Unit 2 Appendix B Environmental Protection Plan is considered completed with submission of deterrent study findings.

RESULTS AND DISCUSSION Nestin Surve S atial Distribution of Lo erhead Turtle Nests Since 1981, 36 1-km-long segments comprising the island's coastline have been surveyed. The distribution of nests among these 36 survey areas has shown an in-crease in nesting from north to south along the northern half of the island (Figure 4; ABI, 1987, 1993). Along the southern half of the island there has either been no gradient or a gradient of decreasing nesting from north to south.

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Though beach dynamics may.,sometimes affect the selection of nesting sites by:

loggerhead turtles (Worth and Smith, 1976; Williams-Walls et al., 1983), no consistent relationship was apparent when field observations of beach widths were compared to the spatial distribution of nests along the island (ABI, 1987). Therefore other factors must also contribute to the selection process. Offshore bottom contours, spatial dis-tribution of nearshore reefs, type and extent of dune vegetation, and degree of human activity on the beach at night have been identified as some of the factors affecting nest-ing (Caldwell, 1962; Hendrickson and Balasingam, 1966; Bustard, 1968; Bustard and Greenham, 1968; Hughes, 1974; Davis and Whiting, 1977; Mortimer, 1982). Relation-ships between spatial nesting patterns and specific environmental conditions are often difficultto establish because of the interrelationship of the factors involved.

Not all ventures onto the beach by a female turtle culminate in successful nests.

These "false crawls" (non-nesting emergences) may occur for many reasons and are commonly encountered at other rookeries (Baldwin and Lofton; 1959; Schulz, 1975; Davis and Whiting, 1977; Talbert et al., 1980; Raymond, 1984). Davis and Whiting (1977) suggested that relatively high percentages of false crawls may reflect disturban-ces or unsatisfactory nesting beach characteristics. Therefore, certain factors may af-feet a turtle's preference to emerge on a beach, while other factors may affect a turtle' tendency to nest after it has emerged. An index which relates the number of nests to the number of false crawls in an area is useful in estimating the post-emergence suitability of a beach for nesting. In the present study this index is termed "nesting suc-cess" and is defined as the percentage of total emergences that result in nests.

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Historically, the pattern of loggerhead emergences on the island has generally paralleled the distribution of nests (ABI, 1987, 1993), and this same trend was apparent in 1993 (Figure 5). In contrast, nesting success by loggerheads along the island has typically lacked gradients (Figure 6; ABI, 1987, 1993). Thus, the relatively high num-bers of loggerhead nests observed in certain areas are usually a result of more turtles coming ashore in those areas rather than of more preferable nesting conditions being encountered by the turtles, after they emerged.

Any of the factors previously identified (i.eoffshore bottom contours, distribution of reefs, type and extent of dune vegetation, and human activity on the beach at night) may affect loggerhead turtle emergence patterns and several have been reported to affect emergence patterns on Hutchinson Island (ABI, 1988, 1989; Martin et al., 1989).

Undoubtedly a combination of factors account for the overall distribution of emergen-ces and therefore the overall nesting pattern on the island.

Nesting surveys on Hutchinson Island were initiated in response to concerns that the operation of the.St. Lucie Plant might negatively impact the local sea turtle rookery.

Previous analysis, using log-likelihood tests of independence (6-test; Sokal and Rohlf, 1981) demonstrated that the construction of the plant's offshore intake and discharge structures significantly reduced nesting at the plant site during construction years 1975, 1981, 1982 and 1983 (Proffitt et al., 1986; ABI, 1987). However, nesting at the plant consistently returned to levels similar to or greater than those at a control site in years following construction (Figure 7). During 1991 when offshore construction was restricted almost entirely to daylight hours, nests were more abundant at the plant site than at the control site. Data collected through 1993 have shown that power plant

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operation exclusive of nighttime intake/discharge:construction has had no apparent ef-fect on nesting.

Lon -Term Trends in Lo erhead Turtle Nestin Various methods were used during surveys prior to 1981 to estimate the total number of loggerhead nests on Hutchinson Island based on the number of nests found in the nine 1.25-km-long survey areas (Gallagher et al., 1972; Worth and Smith, 1976; ABI, 1980a). Each of these methods were subsequently found to consistently overes-

"timate island totals (ABI, 1987). Since whole-island surveys began in 1981, it has been possible to determine the actual proportion of total nests deposited in the nine areas.

This has then allowed extrapolation from the nine survey areas to the entire island for C

years prior to 1981 ~

From 1981 through 1993 the total number of nests in the nine areas varied from 32.5 to 35.6 percent of the total number of nests on the island (Table 1). This is slight-ly higher than the 31.3 percent which would be expected based strictly on the propor-tion of linear coastline comprised by the nine areas. Using the thirteen-year mean of 33.81 percent, estimates of the total number of nests on Hutchinson Island can be cal-culated by multiplying the number of nests in the nine areas by 2.958. This technique, when applied to the nine survey areas during the thirteen years in which the entire is-land was surveyed, produced whole-island estimates within 5.3 percent of the actual number of nests counted. Because the proportion of nests recorded in the nine sur-vey areas remained relatively constant over the last thirteen years, this extrapolation 18

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procedure should provide a fairly accurate estimate of total loggerhead nesting for years prior to 1981.

It is clear that loggerhead nesting activity on Hutchinson Island fluctuates con-siderably from year to year (Table 1; Figure 8). Annual variations in nest densities also are common at other rookeries (Hughes, 1976; Davis and Whiting, 1977; Ehrhart,-1980)

'nd may result from non-annual reproductive behavior (Frazer, 1989). Nonetheless, data collected through 1993 suggest an overall increase in nesting on Hutchinson Is-land since surveys began in 1971. Total nesting activity was greatest during 1991 when 6,812 loggerhead nests were recorded. No relationships between total nesting activity and power plant operation or intake/discharge construction were indicated by year-to-year variations in total nesting on Hutchinson Island.

Seasonal Patterns of Lo erhead Turtle Nestin

.,"The loggerhead turtle nesting season usually begins between mid-April and early -..

May, attains a maximum during June or July, and ends by mid-September (ABI, 1987).

Nesting activity during 1993 followed this same pattern (Figure 9).

Cool water intrusions frequently occur over the continental shelf of southeast Florida during the summer (Taylor and Stewart, 1958; Smith, 1982). Worth and Smith (1976), Williams-Walls et al. (1983) and ABI (1993) suggested that these intrusions may have been responsible for the temporary declines in loggerhead turtle nesting activity previously observed on Hutchinson Island. Temperature data collected during 1993 in-dicated that cool water intrusions occurred during mid-June, late June and early August (Figure 9). Corresponding declines in loggerhead nesting during these periods sug-19

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gest that cool water intrusions also caused temporary nesting declines during the 1993 nesting season.

Though natural fluctuations in temperature have been shown to affect temporal nesting patterns on Hutchinson Island, there has been no indication that power plant operation has affected these temporal patterns (ABI, 1988).

Predation on Lo erhead Turtle Nests Since nest surveys began in 1971, raccoon predation has been a major cause of turtle nest destruction on Hutchinson Island. Researchers at other locations have j

reported raccoon predation levels as high as 70 to nearly 100 percent (Davis and Whit-ing, 1977; Ehrhart, 1979; Hopkins et al., 1979; Talbert et al., 1980). Raccoon predation of loggerhead turtle nests on Hutchinson Island has not approached this level during any study year, though levels for individual 1.25-km-long areas have been as high as 80 percent. Overall predation rates for-survey years 1971 through 1977 were between;,

21 and 44 percent, with a high of 44 percent recorded in 1973. A pronounced decrease in raccoon predation occurred after 1977, and overall predation rates for the nine areas have not exceeded 10 percent since 1979. A decline in predation rates on Hutchinson Island has been variously attributed to trapping programs, construction activities, habitat loss and disease (Williams-Walls et al., 1983; ABI, 1987).

During 1993, seven percent (402) of the loggerhead nests (n =5,752) on the is-land were depredated by raccoons. As in previous years (ABI, 1993), predation of turtle nests was primarily restricted to the most undeveloped portion of the island (i.e., Areas E through S; Figure 10).

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Ghost crabs have been reported by numerous researchers as important predators of sea turtle nests (Baldwin and Lofton, 1959; Schulz, 1975; Diamond, 1976; Fowler, 1979; Hopkins et al., 1979; Stancyk, 1982). Though turtle nests on Hutchinson Island probably have been depredated by ghost crabs since nesting surveys began in 1971, this source of nest destruction did not become apparent until 1983. Quantification of ghost crab predation was initiated the same year.

Overall predation rates by ghost crabs have varied from 0.1 to 2.1 percent from 1983 - 1992 (ABI, 1993). During 1993, 0.1 percent (8) of the loggerhead nests

'(n'='5,752) on the'island were depredated by ghost crabs (Figure 10). Nests destroyed by a combination of raccoon and ghost crab predation have been included as raccoon ~

predations in previous discussions. When these combination predations are included as crab predations, the overall predation rates by ghost crabs range from 0.4 to 3;2 percent. During 1993, 2.5 percent (144 nests) were destroyed by either ghost crabs or a combination of ghost crabs and raccoons.

Green and Leatherback Turtle Nestin Green and leatherback turtles also nest on Hutchinson Island, but in fewer num-bers than loggerhead turtles. Prior to 1981, both survey (nine 1.25-km-long sections) and inter-survey areas were monitored for the presence of green and leatherback nests. Thirty-one kilometers of beach from Area 1 south to the St. Lucie Inlet were in-cluded in that effort. During whole-island surveys from 1981 through 1993, only 2.6 per-cent (7) of the leatherback nests (n = 266) and only 1.4 percent (12) of the green turtle nests (n =831) were recorded on the five kilometers of beach north of Area 1. There-21

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fore, previous counts of green and leatherback nests within the.31 kilometers surveyed probably were not appreciably different from total densities for the entire island. Based on this assumption, green and leatherback nest densities may be compared among all survey years, except 1980, when less than 15 kilometers of beach were surveyed.

Prior to 1993, the number of nests observed on the island ranged from 5 to 146 for green turtles and from 1 to 44 for leatherbacks (Figure 11). During the 1993 survey, 37 green turtle and 10 leatherback turtle nests were'recorded on Hutchinson Island.

Temporal nesting patterns for these species differ from the pattern for loggerhead turtles. Green turtles typically nest on Hutchinson Island from mid-June through the first or second week of September. During 1993, green turtles nested from 12 June through 12 September. Leatherback turtles usually begin nesting in March or April and continue to nest through early to mid-July. During 1993 this species nested from 30 March through 12 July.

Considerable fluctuations in green turtle nesting on the island have occurred among survey years (Figure 11). This is not unusual since there are drastic year-to-year fiuctuations in the numbers of green turtles nesting at other breeding grounds (Carr et al., 1982) Despite these fluctuations, data collected through 1993 suggest an

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overall increase in nesting since 1971 and may reflect an increase in the number of nesting females in the Hutchinson Island area. During 1993, green turtles nested most frequently along the southern half of the island. This is consistent with results of pre-vious surveys.

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Leatherback turtle nest densities have remained low on Hutchinson Island; however, increased nesting during recent years (Figure 11) may reflect an overall in-crease in the number of nesting females in the Hutchinson Island area. During 1993, leatherback turtles primarily nested on the southern half of the island.

Intak anal M nit rin Entrainment of sea turtles at the St. Lucie Plant has been attributed to the presumed physical attractiveness of the offshore structures housing the intake pipes rather than to plant operating characteristics (ABI, 1980b and 1986). The velocity caps supported above the openings to each intake pipe eliminate vertical water entrainment and substantially reduce current velocities near the structures by spreading horizontal draw over an arc of 360 ~ Even when both units are operating at full capacity, turtles must actively swim into the mouth of one of the intake pipes before they encounter cur-rent velocities sufficiently strong,to effect. entrainment.,Consequently,,a turtle'. entrap-ment relates primarily to the probability that it will detect and subsequently enter one ~

of the intake structures.

Relative Abundance and Tem oral Distribution During 1993, a record number of sea turtles were captured in the intake canal of the St. Lucie Plant. All five species inhabiting coastal waters of the southeastern United States were represented, including 147 loggerheads, 179 green turtles, 5 leatherbacks, 4 Kemp's ridleys and 2 hawksbilfs (Table 2). Since intake canal monitoring began in May 1976, 2,230 loggerhead (including 135 recaptures), 558 green (including 15 recap-tures), 15 leatherback, 22 Kemp's ridley and 13 hawksbill captures have taken place 23

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at the St. Lucie Plant. Annual catches for all species combined ranged from a low of 33 in 1976 (partial year of plant operation and monitoring) to 337 in 1993.

Except for 1993, when the green turtle was the most abundant species in the canal, loggerheads have dominated annual captures. Since 1977, the first full year of plant operation, the number of loggerheads captured each year ranged from 62 in 1981 to 195 in 1986 (Figure 12). Numbers have exhibited considerable year-to-year fiuctua-tions with no persistent trends evident.

The number of green turtles captured each year since 1977 has ranged from 3 in 1979 to a record high of 179 in 1993 (Figure 12). Increasing numbers of captures over the last two years may reflect an increase in the number of turtles inhabiting the near-shore coastal area near the plant or may simply represent natural variation. Another, possibility relates to changes in the physical characteristics of the intake structures. As a result of a major reconstruction project undertaken in 1991, the structures may now be more attractive to green turtles, thereby increasing their probability of entrainment.

Additional years of capture data will be required before any long-term population trends can be established.

, During 1993, the monthly catch of loggerheads ranged from 3 (October) to 33 (January), with a monthly mean of 12.3 (+8.5; Table 3). The numbers of captures during October were considerably below average, while captures in January and December were considerably higher than average. Over the entire monitoring period, monthly catches have ranged from 0 to 39, with the greatest number of captures oc-curring during January 1983.

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When data from all full years of monitoring (1977-1993) are combined, the highest mean number of loggerhead captures (16.7 + 9.2) occurred in January; fewest average captures were recorded in November (5.8 + 4.1; Table 3) However, as

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evidenced by minimum and maximum values, monthly catches have shown con-siderable annual variability. Months having relatively low catches one year often have had relatively high catches in another.

Green turtles have been caught during every month of the year, with average monthly catches for all years combined ranging from 0.7 (+0.9) in July to 6.9 (+9.7) in January (Table 4). Seasonal abundance patterns of green turtles have been mu'ch more pronounced than for loggerheads, with 53 percent of all captures occurring be-tween January and March. During March 1993, 55 green turtles were captured, the largest number of captures for this species for-any month on record,

.- Catches of leatherbackshawksbills and Kemp's ridleys have, been infrequent and scattered. throughout the 18 year study period (Figure -13): Each species has shown ~

rather. pronounced seasonal occurrences; 67percent of all leatherbacks were cap-tured in March and April, 61 percent of the hawksbilts were collected between July and September, and 86 percent of the Kemp's ridleys were caught between December and April.

Size-Cia Distributions Although several straight-line and curved measurements were recorded for turtles removed from the intake canal, only one straight-line measurement has been used in analyses presented here. Straight-line carapace length (SLCL) was measured from the 25

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precentral scute to the notch between the postcentral scutes (minimum carapace length of Pritchard et al., 1983). To date, loggerheads removed from the intake canal have ranged in length (SLCL) from 40.2 to 112.0 cm (x = 66.7 + 14.0 cm) and in weight from 10.7 kg to 174.2 kg (x = 49.3 + 31.8 kg).

A carapace length of 70 cm approximates the smallest size of nesting loggerhead females observed along the Atlantic east coast (Hirth, 1980). However, adults can only be reliably sexed on external morphological characteristics (i.e., relative tail length) after attaining a somewhat larger size. Recent data suggest that some males may not ma-ture, and thus might not be distinguishable from females, until they are about 85.0 cm long. Based on these divisions, data were segregatedinto three groups: juveniles (<70 cm), adults (>85 cm) and transitional (7145 cm). The latter group probably includes both mature and immature individuals.

Of the 2,114 loggerhead captures between 1977 and 1993 for which length data were recorded, 69.7 percent were Juveniles, the majority of these measuring between

'50 and 70 cm SLCL (Figure 14; Table 5). The remaining individuals were nearly equal-ly divided between adults and animals in the transitional size class. Similar size-frequen-cy distributions, indicating a preponderance of juveniles, have been reported for loggerheads inhabiting'the Mosquito/Indian River Lagoon (Mendonca and Ehrhart, 1982), the Canaveral ship channel (Kenwood, 1987), and Georgia and South Carolina (Hillestad et al., 1982). These data suggest that coastal waters of the southeastern United States constitute an important developmental habitat for loggerhead sea turtles.

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Seasonal patterns of abundance for various size classes indicated that juvenile loggerheads were slightly more abundant during the winter than at other times of the year (Table 5). About 48 percent of the juveniles were captured between January and April. Abundances decreased in spring and remained relatively constant during the summer and early fall before decreasing again to lowest levels in November. The seasonal distribution of adult loggerheads was much more pronounced, 76 percent of all captures occurring between May and August. This represents the major portion of the nesting season on Kutchinson Island.

Green turtles'removed from the intake canal over the entire study period ranged in size from 20;0 to108.0 cm SLCL (x = 36.5 + 13.4 cm) and 0.9 kg to177.8 kg (x =

9.4 + 17.3 kg). Nearly all (97 percent) were juveniles, with over 75 percent 40 cm or less in length (Figure 15). Although these immature turtles exhibited distinct winter pul-ses, some small individuals were captured throughout the year (Table 4). To date, only 10 adult green turtles (SLCL') 83-cm; Witherington and Ehrhart, "1989) have been removed from the canal; all were captured during or shortly after the nesting season.

The 13 hawksbills removed from the canal ranged in size from 34.0 to 83.4 cm SLCL (x = 48.9 + 14.5 cm) and in weight from 6.4 to 86.6 kg (x = 21.6 + 23.4 kg).

All but two were juveniles (SLCL (63 cm; Witzell, 1983). Similarly, all but one of the 22 Kemp's ridleys captured at the St. Lucie Plant were juveniles (SLCL (60.0 cm; Hirth, 1980). Carapace lengths for the ridleys ranged from 25.9 to 62.0 cm SLCL (x = 37.5

+ 10.6 cm) and weights from 2.8 to 31.8 kg (x = 9.1 + 8.3 kg). The 15 leatherbacks removed from the canal ranged in length from 112.5 to 150.0 cm, and at least 12 were adults (SLCL >121 cm; Hirth, 1980). The largest leatherback for which an accurate 27

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weight was obtained, a female with a curved carapace length of 158.5 cm, weighed 334.8 kg.

Sex Ratios Since intake canal monitoring began in 1976, 329 adult loggerheads (SLCL ) 85.0 cm) have been sexed. Females predominated males by a ratio of 5.8:1.0, which sig-nificantly departs from a 1:1 ratio (X, P (0.05). Consequently, temporal patterns in the number of adult loggerhead captures were heavily influenced by the numbers of females present;.When sexes were separated, it was evident that males were relative-ly evenly distributed among months, whereas 88 percent of the females were taken during the nesting season (May through September; Figure 16).

The number of adult female loggerheads captured at the St. Lucie Plant has in-creased noticeably since 1983. From 1977 (first full year of plant operation) through 1983, an average of 4.6 adult females (+ 3.2; range = 1-10) were entrapped each .

year, whereas since then, an average of 24.9 females per year were captured (+ 6.8; range = 16-35). This increase corresponds to a general rise in loggerhead nesting ac-tivity near the plant (Figure 17). Increased nearshore movement associated with nest-ing increases the probability of a turtle detecting one of the intake structures and hence the probability of entrainment.

Since September 1982, 435 individual juvenile and sub-adult loggerhead turtles (SLCL (70.0 cm) captured in the canal were sexed by Texas A 8 M University re-searchers using a bioimmunoassay technique for blood serum testosterone. Females significantly (X; P <0.05) outnumbered males by a ratio of 2.2:1.0. This female bias is 28

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consistent with findings of Wibbels et al. (1987) for other coastal loggerhead popula-tions in the southeastern United States.

Of the 10 adult green turtles captured since monitoring began, six were males and four were females. Fourteen immature green turtles have been sexed through blood work: 12 females and 2 males, Of the six adult leatherback turtles for which.sex was recorded, three were females and three were males. The two adult hawksbills and one Kemp's ridtey were all females. No sex information exists for juveniles of any of these species.

Ca ture Efficiencies Netting'methodologies have been under continual review and refinement as net materials," configurations and placement have been varied in an effort to minimize sea turtle entrapment times. Additionally, alternative capture techniques have been evaluated and potential deterrent systems tested'in the laboratory. Current capture, procedures have proven to provide a safe, efficient and cost-effective program for removing entrapped turtles from the intake canal, Formal daily inspections of the intake canal are conducted every day that capture nets are deployed (usually five days each week), and the number, location, and rela-tive size of entrapped turtles are recorded on field observation forms. During 1993, about 65 percent of the turtles entering the canal were caught within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of first sighting. Because of differences in mean size, loggerheads typically residedin the canal for shorter periods than the smaller green turtles.

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Since April 1990 when the current daytime netting program was implemented, 93 percent of all loggerheads were captured within one week of first sighting, with a mean entrapment period of 2.7 (+ 4.0) days (Figure 18). Over that same period, green turtles, which are less easily entangled in the large mesh nets, had a mean entrapment time of 3.8 (+ 6.5) days. Ninety-five percent of all green turtles were captured within two weeks of first sighting. Better utilization of currents and eddies, adjustments to tether-ing lines, multi-net deployments and increased efforts to hand capture turtles have con-tributed to.reduced entrapment times during recent years.

Entrapment times may be extended for turtles swimming past the A1A barrier net (ABI, 1987). Prior to barrier net repairs in 1990, the top of the net was occasionally sub-merged or the anchor cable pulled free from the bottom, allowing turtles that would otherwise be restrained by the net to pass. Because'capture efforts west of the A1A bridge were generally less effective than those near the intake headwalls, most turtles breaching the barrier net were not caught until they entered the intake wells of Units 1 and 2. Prior to installation of the UIDS barrier in 1986; about 15 percent of all turtles entrapped in the canal were removed from the intake wells. Because of their relatively small sizes, a much larger proportion of greens (51.6 percent) reached the plant than loggerheads (10.1 percent). Since 1986, the percentage of greens caught at the intake wells has decreased to 24.3 percent, while all loggerheads have been prevented from reaching the plant. During 1993, 40 of the 179 green turtle captures (22.3 percent) oc-curred at the intake wells. One Kemp's ridley was also taken from the intake wells during 1993.

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During 1993, 88 percent of all turtles entrapped in the canal were captured east of the A1A bridge, 259 by netting and 37 by hand. The effective confinement of turtles east of A1A has been a major contributor to the high capture efficiency achieved during recent years.

Relative Condition Turtles captured alive in the intake canal of the St. Lucie Plant were assigned a relative condition based on weight, activity, parasite infestation, barnacle coverage, wounds, injuries and any other abnormalities which might have affected overall vitality.

During 1993, 91.8 percent (135) of all loggerheads found in the canal were alive and in good to excellent condition. Only 8.1 percent (12) of loggerhead captures involved individuals in fair or poor condition. Of the 179 green turtles removed from the intake canal during 1993, 166 (92.7 percent) were in good to excellent condition, 12 (6.7 per-cent) were in fair condition, and 1 (0.6 percent) was dead.

Over the entire monitoring period, about 78 and 84 percent, respectively, of all loggerhead and green captures involved turtles in good to excellent condition (Table 6). Captures of individuals in fair to poor condition occurred about 15 percent of the time for loggerheads and 10 percent of the time for greens. All of the hawksbills and all but one of the leatherbacks were removed from the canal in good to excellent con-dition. About 55 percent of the Kemp's ridleys fell into these categories.

Relative condition ratings can be influenced by a number of factors, some related and others unrelated to entrainment and/or entrapment in the intake canal. Ratings of good to excellent indicate that turtles have not been negatively impacted by their entrap-31

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ment in the canal, at least as evidenced by:physical appearance. Although ratings of fair or poor imply reduced vitality, the extent to which entrainment/entrapment is responsible is often indeterminable. In some instances, conditions responsible for lower ratings, such as injuries, obviously were sustained prior to entrainment.

During 1993, 25 of the 337 turtles captured (7.4 percent) had noticeable injuries, such as missing appendages, broken or missing pieces of carapace or deep lacera-tions. Most of these were old, well-healed wounds, and did not require medical atten-tion.

All but six of the turtles caught during 1993 were released into the ocean im-mediately after capture. Two small green turtles were very lethargic and were held for observation. Relatively low water and air temperatures at the time of their captures were thought to be responsible for this inactivity. Because they otherwise appeared to be in good health, they were released one or two days later. Four other turtles, three logger-heads and one Kemp's ridley, were in obvious ill health or suffered from serious injuries and were transported to Sea World of Florida for appropriate medical treatment and rehabilitation. The Kemp's ridley had a badly cracked carapace and was underweight.

One of the loggerheads had ingested fishing line. The remaining two loggerheads were noticeably underweight, lethargic and heavily infested with barnacles and leeches, a condition referred to as "diseased turtle syndrome". This condition has been reported from several other locales and is unrelated to a turtle's entrapment in the canal (Ehrhart, 1987).

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~Mrt'~iiti Sea turtle mortalities have been closely monitored throughout the life of the canal capture program in an attempt to assign probable causes and take appropriate remedial action to minimize future occurrences. Previous analyses of capture data iden-tified drowning in nets (A1A barrier net, UIDS barrier, and tangle nets), drowning in the intake pipes during periods of reduced intake flow, injuries sustained from dredging operations and injuries sustained from the mechanical rakes used in the intake wells as probable mortality factors (ABI, 1987). Although difficultto quantify, the entrapment and subsequent demise of injured or sick turtles has probably accounted for a portion of observed mortalities.

Over the entire 18 year monitoring period, 130 (5.8 percent) of the 2,230 logger-heads and 24 (4.3 percent) of the 558 green turtles entrapped in the canal were found dead (Table 6). Mortalities spanned the range of size classes for loggerheads (SLCL

= 47.5-103 cm), while all green turtle mortalities involved juveniles less than 42 cm in

'ength. The four Kemp's ridley mortalities documented at the plant during 1987 and 1988 were the only deaths for this species to date; no leatherback or hawksbill mor-talities have occurred at the St. Lucie Plant.

Modifications to capture procedures, improvements to the A1A barrier net and virtual elimination of low flow conditions within the canal have resulted in a substantial reduction in sea turtle mortalities over the life of the canal capture program. Mortality rate, expressed as the percentage of total captures involving dead animals, declined from 7.8 percent during the period 1976-1984 to 4.1 percent since 1984 (Table 2).

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During 1993, only one mortality (0.3=percent of all captures), a small green turtle, was documented. It was removed from the plant's intake wells. Injuries to the carapace suggested that it may have been impacted by the mechanical rakes used to remove debris from the wells. A necropsy performed on the moderately decomposed carcass indicated that the animal was in apparent good health and had been feeding on algae prior to its death.

Re tur Incident

'ince the St.,Lucie Plant capture program began, most turtles removed from the intake canal have been tagged and released into the ocean at various locations along Hutchinson Island. Consequently, individual turtles can be identified as long as they retain their tags. Over the 18 year history of turtle entrapment at the St. Lucie Plant, 92 individuals (78 loggerheads and 14 green turtles) have been removed from the canal more than once. Several other turtles with tag scars have also been recovered, indicat-ing that the actual number of recaptures may be higher.

Of the 78 individual loggerheads known to have been caught more than once, 53 were caught twice and 14 were caught three times. The remainder were captured on four or more separate occasions, with one individual being caught 11 times. Release site did not appear to have any effect on a turtle's probability of being recaptured.

Turtles released both north and south of the plant returned. Recaptures also did not appear to be related to size, as both juveniles and adults were captured more than once (range of SLCL = 47-89 cm). As for overall captures, the majority of recapture incidents involved juveniles (SLCL < 70 cm).

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Recapture intervals for loggerheads ranged from less than one day to 858 days, with a mean of 152 days (+180 days). About 57 percent of all loggerhead recapture incidents occurred within 3 months of previous capture and 89 percent within one year (Figure 19). The average interval between first and last capture was 268 days (+367 days). The longest period between first and last capture was 5.3 years. These data suggest that residency times of loggerheads within the nearshore habitat adjacent to the St. Lucie Plant are relatively short. Similar findings have been reported for loggel'-

heads inhabiting the Mosquito/Indian River Lagoons of east-central Florida (Mendon-ca and Ehrhart, 1982).

All but one of the green turtles caught more than once were captured twice, with one individual being caught three times. Recapture intervals ranged from 10 to 252 days. Mean interval between first and last capture was 111 (+74) days.

SUMMARY

A gradient of increasing loggerhead turtle nest densities from north to south along the northern half of Hutchinson Island has been shown during most survey years. This gradient may result from variations in beach topography, offshore depth contours, dis-tribution of nearshore reefs, onshore artificial lighting and human activity on the beach at night. Low nesting activity in the vicinity of the power plant during 1975 and from 1981 through 1983 was attributed to nighttime construction activities associated with installation of power plant intake and discharge structures. Nesting returned to normal or above normal levels following both periods of construction. During 1991, daytime construction activities associated with velocity cap repairs had no apparent effect on 35

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nesting. Statistical analyses indicate that power plant operation, exclusive of nighttime construction, has had no significant effect on nest densities near the plant.

There have been considerable year-to-year fluctuations in loggerhead nesting ac-tivity on Hutchinson Island from 1971 through 1993. Fluctuations are common at other rookeries and may result from non-annual reproductive behavior.Despite these fluc-tuations, loggerhead nesting activity has remained high during recent years and may reflect an overall increase in the number of nesting females in the Hutchinson Island area. No relationship between total nesting on the island and power plant operation or intake/discharge 'construction was indicated.

Temporal nesting patterns of the Hutchinson Island population may be influenced by natural, large scale fluctuations in water temperature, such as those produced by the cool water intrusions that frequently occur over the continental shelf of southeast Florida during the nesting season. However, localized fluctuations in water tempera-ture associated with power plant operation have had no apparent effect on nesting.

Since nesting surveys began in 1971, raccoon predation was considered the major cause of turtle nest destruction on Hutchinson Island. From 1971 through 1977, overall predation rates in the nine survey areas were between 21 and 44 percent.

However, a pronounced decrease in raccoon predation occurred after 1977, and over-all predation rates in the nine survey areas have not exceeded ten percent since 1979.

Decreased predation by raccoons probably reflects a decline in the raccoon popula-tion. Ghost crab predation on turtle nests may be more significant than previously doc-cumented but remains relatively minor compared to raccoon predation.

36

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During 1993, 37 green turtle and 10 leatherback turtle nests were recorded on Hutchinson Island. Nesting activity by these two species exhibited considerable annual fluctuations, as has been recorded at other rookeries, but has remained relatively high during recent years. This may reflect an overall increase in the number of nesting green and leatherback turtles in the Hutchinson Island area.

During 1993, 147 loggerheads, 179 green turtles, 5 leatherbacks, 2 hawksbills, and 4 Kemp's ridleys were removed from the St. Lucie Plant intake canal. Since monitor-ing began in May 1976, 2,230 loggerhead, 558 green, 15 leatherback, 13 hawksbill and 22 Kemp's ridley turtles have been captured. Over the life of the monitoring program, annual catches for loggerhead turtles have ranged from 33 in 1976 (partial year of plant operation and monitoring) to a high of 195 in 1986. Yearly catches of green turtles have ranged from 0 in 1976 to 179 in 1993. Differences in the number of turtles entrapped during different years and months are attributed primarily to natural variation in the oc-currence of. turtles in the vicinity. of the offshore intake structures, rather than to plant operating characteristics.

Size-class distributions of loggerhead turtles removed each year from the canal have consistently been predominated by juveniles between 50 and 70 cm in straight line carapace length. Over 75 percent of all green turtles entrapped in the canal were juveniles 40 cm or less in length. For both species, the largest number of captures for all years combined occurred during the winter, but these seasonal peaks were much more pronounced for green turtles. Sex ratios of both adult and immature loggerheads caught in the canal continued to be biased towards females.

37

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During 1993, about 92 and 93 percent, respectively, of all loggerheads and green turtles removed from the canal were categorized by physical appearance as being in good to excellent condition. Over the entire 18 year monitoring period, 78 and 84 per-cent, respectively, of ail loggerhead and green turtle captures have involved individuals in these categories; 15 percent of the loggerheads and 10 percent of the green turtles removed from the canal have been in fair or poor condition.

About seven percent of the turtles removed from the intake canal during 1993 had substantial injuries, and most of those were apparently sustained prior to entrapment.

Once in the canal, turtles confined east of A1A typically had very brief residency times.

Thus the relative condition of most turtles was not affected by their entrapment.

During 1993, one green turtle mortality was recorded in the intake canal. Injuries to the carapace suggested that it may have been struck by the rakes used to remove debris from the plant's intake wells. Program modifications, including continual surveil-lance of tangle nets during periods of deployment, improvements to the integrity of the A1A barrier net and greater effort to hand capture turtles have contributed to a sub-stantial decline in sea turtle mortalities during recent years.

38

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'ITERATURE CITED t ABI (Applied Biology, Inc). 1977. Ecological monitoring at the Florida Power & Light Co. St.

Lucie Plant, annual report 1976. Volumes I and II. AB44. Prepared by Applied Biology, Inc. for Florida Power 8 Light Co., Miami.

. 1978. Ecological monitoring at the Florida Power 8 Light Co. St. Lucie Plant, annual report 1977. Volumes I and II. AB-101. Prepared by Applied Biology, Inc. for Florida Power & Light Co., Miami.

. 1979. Florida Power & Light Company, St. Lucie Plant annual non-radiologi-cal environmental monitoring report 1978. Volumes II and III, Biotic monitoring. AB-177. Prepared by Applied Biology, Inc. for Florida Power 8 Light Co., Miami.

. 1980a. Florida Power & Light Company, St. Lucie Plant annual non-radiologi-cal environmental monitoring report 1979. Volumes II and III, Biotic monitoring. AB-244. Prepared by Applied Biology, Inc. for Florida Power & Light Co., Miami ~

. 1980b. Turtle entrainment deterrent study. AB-290. Prepared by Applied Biology, Inc. for Florida Power & Light Co., Miami.

. 1981a. Successful relocation of sea turtle nests near the St. Lucie Plant, Hutchinson Island, Florida. AB-317. Prepared by Applied Biology, Inc. for Florida Power

& Light Co., Miami.

. 1981b. Florida Power & Light Company, St. Lucie Plant annual non-radiologi-cal environmental monitoring report 1980. Volumes II and III, Biotic monitoring. AB-324. Prepared by Applied Biology, Inc. for Florida Power & Light Co., Miami.

. 1981c. Proposed St. Lucie Plant preoperational and operational biological monitoring program - August 1981. AB-358. Prepared by Applied Biology, Inc. for Florida Power 8 Light Co., Miami.

. 1982. Florida Power &. Light Company, St. Lucie Plant annual non-radiologi-cal environmental monitoring report 1981. Volumes II and III, Biotic monitoring. AB-379. Prepared by Applied Biology, Inc. for Florida Power 8 Light Co., Miami.

. 1983. Florida Power & Light Company, St. Lucie Plant annual non-radiologi-cal aquatic monitoring report 1982. Volumes I and II. AB-442. Prepared by Applied Biol-ogy, Inc. for Florida Power & Light Co., Miami.

39

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ABI (Applied Biology, Inc.). 1984a. Florida Power 8 Light Company, St. Lucie Plant annual non-radiological environmental monitoring report 1983. Volumes I and II. AB-530.

Prepared by Applied Biology, Inc. for Florida Power 8 Light Co., Miami.

. 1984b. Florida Power 8 Light Company, St. Lucie Unit 2 annual environ-mental operating report 1983. AB-533, Prepared by Applied Biology, Inc. for Florida Power 8 Light Co., Miami.

. 1985a. Florida Power 8 Light Company, St. Lucie Plant annual non-radiologi-cal environmental monitoring report 1984. AB-553. Prepared by Applied Biology, Inc.

for Florida Power 8 Light Co., Juno Beach.

. 1985b. Florida Power & Light Company, St. Lucie Unit 2 annual environ-mental operating report 1984. AB-555. Prepared by Applied Biology, Inc. for Florida Power 8 Light Co., Juno Beach.

. 1986. Florida Power 8 Light Company, St. Lucie Unit 2 annual environmen-tal operating report 1985. AB-563: Prepared by Applied Biology, Inc. for Florida Power 8 Light Co., Juno Beach.

. 1987. Florida Power 8 Light Company, St. Lucie Unit 2 annual environmen-tal operating report 1986. AB-579. Prepared by Applied Biology, Inc. for Florida Power 8 Light Co., Juno Beach.

. 1988. Florida Power 8'Light Company, St. Lucie Unit 2 annual environmen-tal operating report 1987. AB-595. Prepared by Applied Biology, Inc. for Florida Power 8 Light Co., Juno Beach.

. 1989. Florida Power 8 Light Company, St..Lucie Unit 2 annual environmen-tal operating report 1988. AB-596. Prepared by Applied Biology, Inc. for Florida Power 8 Light Co., Juno Beach.

. 1990. Florida Power 8 Light Company, St. Lucie Unit 2 annual environmen-tal operating report 1989. AB-603. Prepared by Applied Biology, Inc. for Florida Power 8 Light Co., Juno Beach.

. 1991 Florida Power 8 Light Company, St. Lucie Unit 2 annual environmen-

~

tal operating report 1990. AB-610. Prepared by Applied Biology, Inc. for Florida Power 8 Light Co., Juno Beach.

. 1992. Florida Power 8 Light Company, St. Lucie Unit 2 annual environmen-tal operating report 1991. AB-617. Prepared by Applied Biology, Inc. for Florida Power

& Light Co., Juno Beach.

40

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ABI (Applied Biology, Inc.). 1993. Florida Power 8 Light Company, St. Lucie Unit 2 annual en-vironmental operating report 1992. AB-623. Prepared by Applied Biology, Inc. for Florida Power & Light Co., Juno Beach.

Baldwin, W.P., Jr. and J.P. Lofton, Jr. 1959. The loggerhead turtles of Cape Romain, South Carolina. Previously unpublished manuscript abridged and annotated by D.K. Caldwell, without the authors. In D.K. Caldwell and A. Carr, coordinators, The Atlantic logger-head sea turtle, Caretta caretta caretta (L), in America. Bulletin of the Florida State Museum, Biological Sciences, 4(10):319-348.

Bellmund, S., M.T. Masnik and G. LaRoche. 1982. Assessment of the impacts of the St. Lucie 2 Nuclear Station on threatened or endangered species. US Nuclear Regulatory Com-mission, Office of Nuclear Reactor Regulation.

Bustard, H.R. 1968. Protection for a rookery: Bundaberg sea turtles. Wildlife in Australia 5:43-44.

Bustard, H.R. and P. Greenham. 1968. Physical and chemical factors affecting hatching in the green aea turtle, (dhelonia ~mdaa (L.). Ecology 49(2):269-276.

Caldwell, D.K. 1962. Comments on the nesting behavior of Atlantic loggerhead sea turtles,

~ ~

based primarily on tagging returns. Quarterly Journal of the Florida Academy of Scien-

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ces 25(4):287-302.

Caldwell, D.K., A. Carr and L.H. Ogren. 1959. Nesting and migration of the Atlantic logger-head turtle. In D.K. Caldwell and A. Carr, coordinators, The Atlantic loggerhead sea turtle Caretta caretta caretta (L.), in America. Bulletin of the Florida State Museum, Biological Sciences, 4(10):295-308.

t Camp, D.K., N.W. Whiting and R.E. Martin, 1977. Nearshore rriarine ecology at Hutchinson Island, Florida: 1971-1974. V. Arthropods. Florida Marine Research Publications 25:

Carr, A., A. Meylan, J. Mortimer, K. Bjorndal and T. Carr. 1982. Surveys of sea turtle popula-tions and habitats in the Western Atlantic. NOAATechnical Memorandum NMFS-SEFC-91:1-82.

Davis, G.E., and M.C. Whiting. 1977. Loggerhead sea turtle nesting in Everglades National Park, Florida, U.S.A. Herpetologica 33:18-28.

~

ht 9

d,A.W.

t ~ ~ 1916. 6

~ dt ~ tt

~

I gf d tt fh 9 t flit dt,~Wt 9 t imbricata L., on Cousin Island, Seychelles. Biological Conservation 9:199-215.

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I

Ehrhart, LM. 1979. Reproductive characteristics and management potential of the sea turtle rookery at Canaveral National Seashore, Florida. Pages 397-399 in Linn, R.M., ed.

Proceedings of the First Conference on Scientific Research in the National Parks, 9-12 November, 1976, New Orleans, La. NPS Trans. and Proc. Ser. No. 5.

Ehrhart, L.M. 1980. Threatened and endangered species of the Kennedy Space Center:

marine turtle studies. In A continuation of baseline studies for environmentally monitor-ing space transportation systems (STS) at John F. Kennedy Space Center. Contract No. NAS-10-8986. Vol IV, NASA Report 163122. September 1980.

~

~ 1987. Marine turtle mortality in the vicinity of Port Canaveral, Florida, 1977-84. In W.N.

Witzell, editor, Ecology of East Florida Sea Turtles, pages 1-20. NOAATechnical Report NMFS 53.

Ernest, R.G., R.E. Martin, B.D. Peery, D.G. Strom, J.R. Wilcox and N.W. Walls. 1988. Sea turtle entrapment at a coastal power plant. Pages 270401 in Mahadevan, K., R.K. Evans, P.

Behrens, T. Biffar and L Olsen, eds. Proceedings, Southeastern Workshop on Aquatic Ecological Effects of Power Generation. Report No. 124, Mote Marine Laboratory, Sarasota, Florida.

Ernest, R.G., R.E. Martin, N.W. Walls and J.R. Wilcox. 1989. Population dynamics of sea turtles

~ ~ ~ ~

utilizing shallow coastal waters off Hutchinson Island, Florida. Pages 57-59 in Eckert,

'.A., K.L. Eckert and T.H. Richardson, compilers. Proceedings of the Ninth Annual

~ ~ ~ ~

t Workshop on Sea Turtle Conservation and Biology. NOAA Technical Memorandum NMFS-SEFC-232.

F owler, L.E. 1979. Hatching success and nest predation in the green sea turtle, Chelonia

~mdas at Tortuguero, Costa Rica. Ecology 60(5):645-955.

Frazer, N.B. 1989. Nesting cycles in sea turtles: typical, but not cycles. Pages 61-64 in Eck-ert, S.A., K.L Eckert and T.H. Richardson, compilers. Proceedings of the Ninth Annual Workshop on Sea Turtle Conservation and Biology. NOAA Technical Memorandum NMFS-SEFC-232.

i Futch, C.R. and S.E. Dwinell. 1977. Nearshore marine ecology at Hutchinson Island, Florida:

1971-1974. IV. Lancelets and Fishes. Florida Marine Research Publications 24: 1-23.

L Gallagher, R.M. 1977. Nearshore marine ecology at Hutchinson Island, Florida: 1971-1974.

II. Sediments. Florida Marine Research Publications 23: 6-24.

r Gallagher, R.M. and M.L. Hollinger. 1977. Nearshore marine ecology at Hutchinson Island, Florida: 1971-1974. I. Introduction and rationale. Florida Marine Research Publications 23: 1-5.

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Gallagher, R.M., M.L Hollinger, R.M. Ingle and C.R. Futch. 1972. Marine turtle nesting on Hutchinson Island, Florida in 1971. Florida Department of Natural Resources, Special Scientific Report 37:1-11.

I Hendrickson, J.R. and E. Balasingam. 1966. Nesting beach preferences of Malayan sea turtles. Bulletin of the National Museum Singapore 33(10):69-76.

t Henwood, T.A. 1987. Movements and seasonal changes in loggerhead turtle, Caretta caret-ta aggregations in the vicinity of Cape Canaveral, Florida (1978-84). Biological Con-i servation 40:191-202.

Hiltestad, H.O., J.l. Richardson, C. McVea, Jr. and J.M. Watson, Jr. 1982. Worldwide inciden-I tal capture of sea turtles. Pages 489%96 in Bjorndal, K.A., ed. Biology and conserva-tion of sea turtles. Smithsonian Institution Press, Washington, D.C.

Hirth, H.F. 1980. Some aspects of the nesting behavior and reproductive biology of sea turtles.

~ ~ ~

~

American Zoologist 20:507-523. ~

Hopkins, S.R., T.M. Murphy, Jr., K.B. Stansell and P.M. Wilkinson. 1979. Biotic and abiotic

~ ~ ~ ~ ~

factors affecting nest mortality in the Atlantic loggerhead turtle. Proceedings Annual Conference of Southeastern Fish and Wildlife Agencies 32:213-223.

~

~

i Hughes, G.R. 1974. The sea turtles of southeast Africa, 1. Status, morphology and distribu-

~

~ ~ ~ ~

tions. South African Association for Marine Biological Research, Oceanographic Research Institute, Investigational Report No. 35:1-144.

I . 1978. Irregular reproductive cycles in the Tongaland loggerhead sea turtle, Caretta caretta (L.) (Cryptodira:Chelonidae). Zoologica Africans 11(2):285-29'l.

i Lyons, W.G. 1989. Nearshore marine ecology at Hutchinson Island, Florida: 1971-1974. Part XI. Mollusks. Florida Marine Research Publication 47:1-131.

Magnuson, J.J., K.A. Bjorndal, W.D. DuPaul, G.L. Graham, D.W. Owens, C.H. Peterson, P.C.H. Pritchard, J.l. Richardson, G.E. Saul, and C.W. West. 1990. Decline of the sea turtles: causes and prevention. National Academy Press, Washington, D.C. 259p.

t Martin, R.E., R.G. Ernest, N.W. Walls and J.R. Wilcox. 1989a. Size distribution and seasonal abundance of loggerhead and green turtles in nearshore waters off Hutchinson Island, Florida. Pages 334-335 in Ogren, L., F. Berry, K. Bjorndal, H. Kumpf, R. Mast, G.

Medina, H. Reichart and R. Witham, editors. Proceedings of the Second Western At-lantic Turtle Symposium. Mayaguez, Puerto Rico, 12-16 October 1987. NOAA Techni-cal Memorandum NMFS-SEFC-226.

43

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~ k

~

~

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Martin, R.E., R.G. Ernest, N.W. Walls and J.R. Wilcox. 1989b. Long-term trends in sea turtle nesting on Hutchinson Island, Florida. Pages 111-113 in Eckert, S.A., K.L. Eckert and T.H. Richardson, compilers. Proceedings of the Ninth Annual Workshop on Sea Turtle Conservation and Biology. NOAA Technical Memorandum NMFS-SEFC-232.

i Mendonca, M.T. and L.M. Ehrhart. 1982. Activity, population size and structure of the imma-ture Cheionia ~mdas and Caretta caretta in Mosquito Lagoon, Florida. Copeia1982 (1) 161-167.

MoNer, M.D. and J.F. Van Breedveld. 1979. Nearshore marine ecology at Hutchinson Island, r Florida: 1971-1974.X. Benthic algae species list. Florida Marine Research Publications 34: 118-122.

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)" '

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NMFS (National Marine Fisheries Service). 1978. Final EIS listing and protecting the green sea turtle (Chelonia ~mdas, loggerhead sea turtle (Caretta ~caretta and the Pacific Ridley sea turtle e idochel s ~olivacea under the Endangered Species Act of 1973. Nation-al Marine Fisheries Service, Dept. of Commerce, Washington, D.C.

NRC (US Nuclear Regulatory Commission). 1982. Final environmental statement related to r the operation of St. Lucie Plant Unit 2. Docket No. 50-389.

O'ara, J.'1980. Thermal influences on the swimming speed of loggerhead turtle hatchlings.

I Copeia 1980(4):773-780.

l Owens, D.W., J.R. Hendrickson, V. Lance and I.P. Callard. 1978. A technique for determin-ing sex of immature Chelonia ~mdas using a radioimmunoassay. Herpetologica 34:270-273.

t Owens, D.W. and G.J. Ruiz. 1980. New methods of obtaining blood and cerebrospinal fluid from marine turtles. Herpetologica 36:17-20.

Pritchard, P.C., P.R. Bacon, F.H. Berry, A.F. Carr, J. Fletemeyer, R.M. Gallagher, S.R. Hop-kins, R.R. Lankford, R. Marques M., L.H. Ogren, W.G. Pringle, Jr., H.A. Reichart and R. Witham. 1983. Manual of sea turtle research and conservation techniques. Prepared for the Western Atlantic Turtle Symposium, San Jose, Costa Rica, July 1983. 126 pp.

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Proffitt, C.E;-, R.E. Martin, R.G. Ernest, B.J. Graunke, S.E. LeCroy, K.A. Muldoon, B.D. Peery, J.R. Wilcox and N. Williams-Walls. 1986. Effects of power plant construction and opera-tion on the nesting of the loggerhead sea turtle (Caretta ~caretta:1971-1984. Copeia 1986(3): 813-816.

Raymond, P.W. 1984. The effects of beach restoration on marine turtles nesting in south Brevard County, Florida. M.S. thesis, University of Central Florida.

Routa, R.A. 1968. Sea turtle nest survey of Hutchinson Island, Florida. Quarterly Journal i Florida Academy of Sciences 30(4):287-294.

Schulz,.J.P. 1975. Sea turtles nesting in Surinam. Zoologische Verhandelingen, uitgegeven door het Rijksmuseum van Natuurlijke Historic te Leiden, No. 143:1-144.

Smith, N.P. 1982. Upwelling in Atlantic shelf waters of south Florida. Florida Scientist 45(2):125-t 138.

Sokal, R.R. and F.J. Rohlf. 1981. Biometry. The principles and practice of statistics in biologi-r cal research. W.H. Freeman and Company, San Francisco. 859 pp.

tancyk, S.E. 1982. Non-human predators of sea turtles and their control. Pages 139-152 in

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Bjorndal, K.A., ed. Biology and Conservation of Sea Turtles. Smithsonian Institution

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l Press. Washington, D.C. ~ ~

Talbert, O.R., S.E. Stancyk, J.M. Dean and J.M. Will. 1980. Nesting activity of the loggerhead I turtle (Caretta ~caretta in South Carolina. I: A rookery in transition. Copeia 1980:(4)709-718.

t Taylor, C.B., and H.B. Stewart. 1958. Summer upwelling along the east coast of Florida. Jour-nal of Geophysical Research 64(1):33-40.

i Tester, L.A. and K.A. Steidinger. 1979. Nearshore marine ecology at Hutchinson Island, Florida: 1971-1974. Vll. Phytoplankton, 1971-1973. Florida Marine Research Publica-tions 34: 16-61.

Walker, L.M. 1979. Nearshore marine ecology at Hutchinson Island, Florida: 1971-1974. IX.

I Diel plankton, 1973-1974. Florida Marine Research Publications 34: 99-117.

Walker, L.M., B.M. Glass and B.S. Roberts. 1979. Nearshore marine ecology at Hutchinson t Island, Florida: 1971-1974. Vill. Zooplankton, 1971-1973. Florida Marine Research Publications 34: 62-98.

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Walker, LM. and K.A. Steidinger. 1979. Nearshore marine ecology at Hutchinson Island, Florida: 1971-1974. Vl. Plankton dynamics, 1971-1973. Florida Marine Research Publications 34: 1-15.

i Wibbels, T., R.E. Martin, D.W. Owens, and M.S. Amoss, Jr. 1991. Female-biased sex ratio of immature loggerhead sea turtles inhabiting the Atlantic coastal waters of Florida.

Canadian Journal of Zoology. 69:2973-2977.

'Wibbels, T., D.W. Owens, Y. Morris, and M. Amoss. 1987. Sexing techniques and sex ratios for immature loggerhead sea turtles captured along the Atlantic coast of the United States. Pages 65-74 in W.N. Witzell, editor. Ecology of East Florida Sea Turtles. NOAA Technical Report NMFS-53.

I Williams-Walls, N., J. O'ara, R.M. Gallagher, D.F. Worth, B.D. Peery and J.R. Wilcox. 1983.

Spatial and temporal trends of sea turtle nesting on Hutchinson Island, Florida, 1971-1979.'Bulletin of Marine Science 33(1):55-66.

Witherington, B.E. and L.M. Ehrhart. 1989. Status and reproductive characteristics of green turtles (Chelonia ~mdas nesting in Florida. Pages 35t452 in Ogren, L., F. Berry, K.

Bjorndal, H. Kumpf, R. Mast, G. Medina, H. Reichart and R. Witham, editors. Proceed-ings of the'Second Western Atlantic Turtle Symposium. Mayaguez, Puerto Rico, 12-16 October 1987. NOAA Technical Memorandum NMFS-SEFC-226.

Wl II WN ISSS St p I Ill I pt Id I Ih h h stilt NI,~WN I I pl (Linnaeus, 1766). FAO Fisheries Synopsis, 137:1-78.

t Worth, D.F. and M.L. Hollinger. 1977. Nearshore marine ecology at Hutchinson Island, Florida:

1971-1974. III. Physical and chemical environment. Florida Marine Research Publica-tions 23: 25-85.

Worth, D.F., and J.B. Smith. 1976. Marine turtle nesting on Hutchinson Island, Florida, in 1973.

t Florida Marine Research Publications 18:1-17.

46

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85.0 cm) in the intake canal, St. Lucie Plant, 1977-1993, and numbers of loggerhead emergences in Area 4 adjacent to the plant. (Nesting activity was not monitored in 1978).

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0 86 M 4S GO 55 60 DAYS BETWEEN FIRST SIGHTING AND CAPTURE Figure 18. Capture efficiency, expressed as days between first sighting and capture, for loggerhead (N = 416) and green turtles (N = 252) entrapped in the ihtake canal, St. Lucie Plant, April 1990 through December 1993.

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M 80 70 60 II 60 40 30 + INTERVAL BETHEEN SUCCESSIVE CAPTURES O INTERVAL BETWEEN FIRST AND LAST CAPTURE

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Figure 19. Recapture intervals for loggerheads entrapped more than once in the intake canal, St. Lucie Plant, 1976-1993. Intervals represent either time between successive captures (N = 132) or time between first and last captures (N = 75).

Cumulative percentage is the fraction of all recaptures occurring within a given interval. (Intervals between first and last capture exceeded 36 months for 4 individuals.)

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TABLE 1 ESTIMATES OF THE NUMBERS OF LOGGERHEAD TURTLE NESTS ON HUTCHINSON ISLAND BASED ON SURVEYS OF NINE 1.25-KM-LONG SURVEY AREAS, 1S71 - 1993, COMPARED TO THE ACTUALNUMBER OF NESTS ON THE ISLAND, 1981 - 1993 Extrapolation from the Actual number Number of nests in the nine nine sunrey areas to the of nests on the 1971 1420 4200 1973 1260 3727 1975 1493 4416 1977 2757 1979 1449 4286 1981 1031 3050 3115 1982 1634 4690 1983 1592 4709 4743 1984 1439 4257 4277 1623 4801 4877 1986 1839 5483 1987 4623 1988 1701 5032 4990 1989 1774 5247 5193 2177 6440 6700 1991 2409 7126 6812 1992 2150 6459 1878 5555 5752

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TABLE 2 TOTAL NUMBER OF SEA TURTLE CAPTURES AND (NUMBER OF DEAD) TURTLES REMOVED FROM THE INTAKE CANAL ST. LUCIE PLANT, 1976- 1993 1976 ss(4) ss(4) 1977 80(5) 5(2) 86(7) 1978 138(19) 6(1) 148(20) 1979 172(13) s(1) 175(14) 1980 116(5) 10(s) 126(8) 1981 62(5) 32(2) 97(7) 1982 101(16) 8 110(16) 1983 119(4) 2s(4) 142(8) 1984 148(3) 69(2) 220(5) 1985 157(4) 14 172(4) 1986 195(27) 22(1) 1 220(28) 1987 175(11) 35 6(2) 218(13) 1988 134(6) 42(2) 5(2) 181 (10) 1989 111(4) 17(1) 2 133(5) 112(1) 20(2) 132(3) 1991 107(1) 12 121(1) 1992 12S(2) 61(2) 1 2 187(4) 147 179(1) 5 2 4 337(1)

Total 2230(130) 558(24) 15(0) 13(0) 22(4) 2838(158)

Annual Mean 129.2 32.8 0.9 0.8 1.3 165.0 Std. Deviation 34.4 42.2 1.4 0.8 1.9 61.0 Excludes 1976 (partial year of plant operation).

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TABLE 3 TOTAL NUMBER OF LOGGERHEAD TURTLES REMOVED EACH MONTH FROM THE INTAKE CANAL ST. LUCIE PLANT, 1977 -1993 1977 Throu h 1993 Number of Percent of Standard January 12.9 39 16.7 9.2 February 213 97 29 12.5 5.6 March 8.7 27 11.2 6.9 15 April 198 9.0 24 11.7 7.1 May 8.3 28 10.8 8.5 June 11.2 30 14.5 9.1 July 209 9.2 27 11.9 8.9 15 August 197 8.9 34 11.5 8.9 September 6.5 19 8.3 5.5 October 139 6.0 17 7.8 5.3 November 103 4.5 15 5.8 4.1 December 123 5.2 14 6.7 4.4 14 Total 2197 39 147 Mean 10.8 12.3 Std. Deviation 7.6 8.5 First full year of plant operation. An additional 33 loggerheads were captured during 1976.

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TABLE 4 TOTAL NUMBER OF GREEN TURTLES REMOVED EACH MONTH FROM THE INTAKE CANAL ST. LUCIE PLANT, 1977 -1993 1977 Throu h 1993 Number of Percent of Standard January 118 21.1 37 6.9 9.7 16 February 15.4 28 5.1 6.8 28 March 16.1 55 5.3 13.0 55 April 8.1 23 2.7 5.3 23 May 18 3.2 2.0 June 3.9 1.7 July 2.0 0.7 0.9 August 15 2.7 0.9 September 13 2.3 0.8 1.5 October 38 6.8 18 2.2 4.4 November 47 8.4 14 2.8 4.2 14 December 55 9.9 19 3.2 5.3 19 Total 558 55 179 Mean 2.7 14.9 Std. Deviation 6.0 15.4 First full year of plant operation.

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TABLE 5 NUMBER OF MONTHLYCAPTURES BY SIZE CLASS FOR LOGGERHEAD TURTLES REMOVED FROM THE INTAKE CANAL ST. LUCIE PIANT, 1977-1993 Size classes SLCL in cm January 22 122 92 236 16.0 29 9.4 7 4 0 3.3 February 15 87 71 173 11.7 21 6.8 2 4 0 1.8 March 55 152 10.3 21 6.8 1 6 2 2.7 April 18 141 9.6 31 10.1 3 8 0 3.3 May 14 117 7.9 17 5.5 16 28 1 45 13.5 June 13 55 113 7.7 35 11.4 48 37 3 88 26.3 July 52 36 92 6.2 33 10.7 30 40 5 75 August 47 52 106 7.2 37 12.1 24 22 47 14.1 September 58 105 7.1 16 5.2 6 9 2 17 5.1 October 41 38 88 6.0 30 9.8 6 2 1 2.7 November 30 26 62 4.2 21 6.8 4 5 1 10 3.0 December 50 32 88 6.0 16 5.2 4 0 1.8 Total 130 751 592 1473 307 149 169 16 334

% of Total 69.7 14.5 15.8 Excludes 1976 (partial year of data).

No data were collected for 83 individuals.

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TABLE 6 RELATIVE CONDITION OF SEA TURTLES REMOVED FROM THE INTAKE CANAL ST. LUCIE PLANT, 1976- 1993 Relative 529 23.7 295 52.9 2 13.3 4 182 11 84.6 841 29.6 640 28.7 109 19.5 5 33.3 5 22.7 2 15.4 761 26.8 579 26.0 67 12.0 7 46.7 3 13.6 656 23.1 246 11.0 50 9.0 1 6.7 3 13.6 300 10.6 79 3.5 8 1.4 3 13.6 90 3.2 130 5.8 24 4.3 4 182 158 5.6 27 1.2 5 0.9 32 1.1 Total 2230 558 13 2838 1 Excellent: normal or above normal weight, active, very few or no barnacles or leeches, no wounds.

2 Very good: intermediate good to excellent.

3 Good: normal weight, active, light to medium coverage of barnacles and/or leeches, wounds absent, healed or do not appear to debilitate the animal.

4 Fair: intermediate poor to good.

5 Poor: emaciated, slow or inactive, heavy barnacle coverage and/or leech infestation, debilitating wounds or missing appendages.

6 Dead 7 Alive but otherwise condition not recorded.

FLORIDA POWER & LIGHT COMPANY ST. LUCIE UNIT 2 ANNUALENVIRONMENTALOPERATING REPORT (FPI 93)

APRIL 1994 VOLUME II

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ANNUALENVIRONMENTALOPERATING REPORT I. Introduction The St. Lucie Unit 2 Environmental Protection Plan (EPP) requires the submittal of an annual report for various activities at the plant site including the reporting on sea turtle monitoring programs, and other matters related to Federal and State environmental permits and certifications.

'his rcport and Volume I described below fulfillthese reporting requirements.

Sea Turtle Monitorin and Associated Activities A rcport on aquatic and terrestrial sea turtle monitoring programs as described in EPP Sections 4.2.1 (Beach Nesting Surveys), 4.2.3 (Studies to Evaluate and/or Mitigate Intake Canal Mortality) and 4.25 (Capture and Release Program) is concurrently submitted in a separate report (AB-631 Vol. I) prepared by Applied Biology, Inc. of Jensen Beach, Florida and Atlanta, Georgia.

Studies to evaluate and/or mitigate intake entrapment required by Section 4.2.2 of the EPP have been previously performed. A final report was submitted to the Office of Nuclear Reactor Regulation on April 18, 1985. With submittal of that report, the EPP requirement was fulfilled and will not be readdressed in this or future reports.

Surveillance and maintenance of the light screen to minimize sea turtle disorientation as required by Section 4.2.4 of the EPP is ongoing. The Australian Pine light screen or other vegetation located on the beach dune between the power plant and the ocean is routinely surveyed to determine its overall vitality. The vegetation line is surveyed for any gaps occurring from mortality, which would result in unacceptable light levels on the beach. Trees, vegetation or shade cloth are replaced as necessary to maintain the overall integrity of the light screen.

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III. Other Routine Re orts The following items for which reporting is required are listed by section number from the plant's Environmental Protection Plan (EPP):

5.4.1(a) EPP NONCOMPLIANCES AND CORRECTIVE ACTIONS TAKEN No noncompliances under EPP Section 5.4.1(a) were determined to have occurred during 1993.

5.4.1(b) CHANGES IN STATION DESIGN OR OPERATION TESTS AND EXPERIMENTS IN ACCORDANCE WITH EPP SUBSECTION 3.1 No plant site activities were determined to be reportable under Section 5.4.1(b) during 1993.

5.4.1(c) NONROUTINE REPORTS SUBMFITED TO THE NRC FOR THE YEAR 1993 IN ACCORDANCE WITH EPP SUBSECTION 5.4.2:

1. Report concerning a CERCLA reportable release of hydrazine to the onsite stormwater basin; reported to the NRC on January 14, 1993.

2. Report concerning an exceedance of the NPDES Permit maximum pH limitation for Neutralization Basin effluent; reported to the NRC on March 5, 1993.

3. Report concerning increased sea turtle entrapment in the plant's condenser cooling water intake canal; reported to the NRC on April 14, 1993.

4. Report concerning an exceedance of the NPDES Permit minimum pH limitation for sewage treatment plant effluent; reported to the NRC on July 6, 1993.

5. Report concerning an exceedance of the NPDES Permit maximum limitation for the once through cooling water system biocide treatment chemical, Clamtrol, CT - 1; reported to the NRC on November 1, 1993.

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