L-2024-054, 2023 Annual Environmental Operating Report

2023 Annual Environmental Operating Report

ML24101A197
Person / Time
Site:	Saint Lucie
Issue date:	04/09/2024
From:	Catron S Florida Power & Light Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
L-2024-054
Download: ML24101A197 (1)

Text

April 09, 2024 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 Re:

St. Lucie Units 1 and 2 Docket Nos. 50-335 and 50-389 2023 Annual Environmental Operating Report L-2024-054 10 CFR 50.4 In accordance with Section 5.D.1.b. of the St. Lucie Units 1 and 2 Environmental Protection Plans (EPP), attached is the Annual Environmental Operating Report for calendar year 2023.

If you have any questions regarding this submittal, please contact Kenneth Mack at 561-904-3635.

Sincerely, Steve C ron Licensin and Regulatory Compliance Director - Nuclear Fleet Florida Power & Light Company

Attachment:

Florida Power & Light Company - St. Lucie Plant - Annual Environmental Operating Report 2023 cc:

FDEP Siting Office Florida Power & Light Company 6501 S. Ocean Drive, Jensen Beach, FL 34957

FLORIDA POWER & LIGHT COMPANY ST. LUCIE PLANT ANNUAL ENVIRONMENTAL OPERATING REPORT 2023 FLORIDA POWER & LIGHT COMPANY JUNO BEACH, FLORIDA INWATER RESEARCH GROUP, INC.

JENSEN BEACH, FLORIDA

Environmental Operating Report Table of Contents Acronyms......................................................................................................................... 4 Executive Summary......................................................................................................... 5 1.0 Background........................................................................................................... 7 1.1 Area Description................................................................................................ 7 1.2 Plant Description............................................................................................... 7 1.3 Environmental Reporting................................................................................... 7 2.0 Sea Turtle Nest Monitoring................................................................................... 8 2.1 Methodology...................................................................................................... 8 2.1.1 Previous Methods & Projects....................................................................... 8 2.1.2 Current Methods........................................................................................ 1 O 2.2 Results for 2023.............................................................................................. 11 2.2.1 Loggerhead Nesting................................................................................... 12 2.2.2 Green Nesting............................................................................................ 12 2.2.3 Leatherback Nesting.................................................................................. 13 2.2.4 Predation.................................................................................................... 14 2.2.5 Poaching.................................................................................................... 14 3.0 Intake Canal Monitoring...................................................................................... 15 3.1 Barrier Nets..................................................................................................... 15 3.1.1 Background................................................................................................ 15 3.1.2 Current Methods & Results........................................................................ 17 3.2 Intake Pipe Cleaning & Maintenance............................................................... 17 3.3 Power Plant Outages....................................................................................... 17 4.0 Intake Canal Captures........................................................................................ 17 4.1 Methodology.................................................................................................... 18 4.1.1 Turtle Capture............................................................................................ 18 4.1.2 Data Collection........................................................................................... 19 4.2 Results for 2023.............................................................................................. 19 4.2.1 Loggerhead Captures................................................................................ 20 4.2.2 Green Captures.......................................................................................... 20 4.2.3 Leatherback, Hawksbill, Kemp's, & Olive Ridley Captures......................... 21 4.2.4 Recaptures................................................................................................. 21

4.2.5 Relative Condition...................................................................................... 22 4.2.6 Mortalities & Injuries................................................................................... 23 4.2.7 Intake Canal Nesting.................................................................................. 24 4.2.8 Smalltooth Sawfish and Giant Manta Ray Captures.................................. 24 5.0 Sea Turtle Protective Activities........................................................................... 25 5.1 NMFS Section 7 Consultations........................................................................ 25 5.2 Sea Turtle Stranding & Salvage Network and Turtle Walks............................ 27 5.2.1 Results for 2023......................................................................................... 27 5.3 Collaborative Efforts........................................................................................ 28 6.0 References.......................................................................................................... 29 7.0 Figures & Tables................................................................................................. 34 8.0 Annual Environmental Operating Report............................................................. 51 8.1 lntroduction...................................................................................................... 51 8.2 Sea Turtle Monitoring & Associated Activities................................................. 51 8.3 Taprogge Condenser Tube Cleaning System Operation................................. 51 8.4 Nonroutine Reports......................................................................................... 52 8.5 Routine Reports............................................................................................... 52 8.6 Figures & Tables............................................................................................. 53

Acronyms ABI BO DEP EAi ESA EPP FAU FPL FWC HBOI IRG LMC NMFS NRC PIT SSCL STSSN UESI UIDS Applied Biology, Inc.

Biological Opinion Department of Environmental Protection Ecological Associates, Inc.

Endangered Species Act Environmental Protection Plan Florida Atlantic University Florida Power & Light Florida Fish and Wildlife Conservation Commission Harbor Branch Oceanographic Institute lnwater Research Group, Inc.

Loggerhead Marinelife Center National Marine Fisheries Service Nuclear Regulatory Commission Passive Integrated Transponder Straight Standard Carapace Length Sea Turtle Stranding and Salvage Network Underwater Engineering Services, Inc.

Underwater Intrusion Detection System 4

Executive Summary Florida Power & Light's (FPL) St. Lucie Plant, located on South Hutchinson Island, consists of two 1,000 MWe nuclear-fueled electric generating units that use nearshore ocean water for the plant's once-through condenser cooling system. Water for this system enters through three submerged intake structures located 365 m offshore. Water passes through the structures and into submerged pipes (two 3. 7 m and one 4.9 m in diameter) running under the beach. It then passes into a 1,500 m long intake canal, which transports water to the plant. Turtles entering the ocean intake structures are entrained with cooling water and transported through the intake pipes into the enclosed canal system where they must be manually captured and returned to the ocean.

South Hutchinson Island is also an important rookery for loggerhead ( Caretta caretta),

green (Che/onia mydas), and leatherback (Dermoche/ys coriacea) turtles. Under the Endangered Species Act (ESA), the federal government has classified loggerhead and green turtles as threatened species while leatherbacks are classified as endangered. One of FPL's primary environmental concerns is to ensure that the operation of the St. Lucie Plant does not adversely affect sea turtle nesting. To monitor nesting trends, they have sponsored nesting surveys on the island since 1971. Biologists use all-terrain vehicles to survey the island each morning during nesting season. New nests, non-nesting emergences (false crawls), and nests negatively affected by predators are recorded. Data collected from beach nesting surveys are reported to the Florida Fish and Wildlife Conservation Commission (FWC) as part of a statewide survey program. In 2023, 14,360 loggerhead, 2,270 green, and 338 leatherback nests were recorded on South Hutchinson Island.

Since the plant became operational in 1976, turtles entrained in the intake canal have been systematically captured, measured, weighed, tagged, and released. During 2023, 921 sea turtles were removed from the intake canal, including 355 loggerheads, 557 greens, four Kemp's ridleys (Lepidoche/ys kempil), two hawksbills (Eretmoche/ys imbricata), two leatherbacks, and one olive ridley (Lepidoche/ys o/iviacae). Most of these turtles (97.7%) were captured alive and released back into the ocean. Twenty (2.2%)

were taken to rehabilitation facilities for treatment of injuries or disease and one turtle (0.1 %) was recorded as deceased.

Injuries and mortalities are categorized in two ways - causal to plant operations or non-causal to plant operations. These decisions are made in consultation with FWC and/or a qualified veterinarian. Not all mortalities and injuries are causal to plant operations, as some sea turtles enter the canal in either a moribund state or have pre-existing conditions related to disease, fisheries interactions, boat strikes, or shark attacks. Injuries causal to plant operations are recorded and are applied against the take 5

limit. The National Marine Fisheries Service (NMFS) issued a new Biological Opinion (BO) in August 2022. NMFS, based on fisheries experience, believed a 3-year period was more appropriate for setting take limits while reducing the likelihood of requiring reinitiation of ESA Section 7 consultation unnecessarily and issued new take limits based on the 3-years.

During 2023, there was one causal green turtle mortality and one causal green turtle injury. No hawksbill, Kemp's ridley, loggerhead, leatherback, or olive ridley turtles were injured or killed due to plant operation. One smalltooth sawfish (Pristis pectinata) was captured in the intake canal. No giant manta rays (Mobula birostris) were encountered at the St. Lucie Power Plant. Therefore, FPL has not exceeded the take limit for the 3-year period (2022 - 2024) under the latest BO issued by NMFS.

Three loggerheads and three green turtles nested on the canal banks during the 2023 sea turtle nesting season. The nests were relocated and later excavated to determine hatch success in accordance with FWC protocols.

The current BO also mandates that FPL participate in the Sea Turtle Stranding and Salvage Network (STSSN) as well as Public Service Turtle Walks. As participants in the STSSN, biologists routinely respond to sea turtle strandings in St. Lucie and Martin Counties. This activity involves the collection of information about turtles that are found dead, debilitated, or that have been impacted by human-related activities. During 2023, lnwater Research Group (IRG) biologists responded to 14 stranding events. Sea turtle nesting walks are conducted by FPL as public service programs during the summer sea turtle nesting season. Twelve turtle walks were conducted during 2023, with 237 members of the public participating.

The St. Lucie Plant sea turtle program continues to assist other sea turtle researchers, universities, nonprofit organizations, and state and federal agencies by providing data, specimens, and public outreach. Biologists collaborated with researchers on seven projects in 2023.

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1.0

Background

1.1 Area Description Florida Power & Light's (FPL) St. Lucie Plant is located on a 457-hectare site on South Hutchinson Island on Florida's east coast (Figures 1 & 2). South Hutchinson Island is a barrier island that extends 36 km between inlets and attains its maximum width of 2 km at the plant site. The plant is approximately midway between the Fort Pierce and St. Lucie Inlets and is bounded on the east by the Atlantic Ocean and on the west by the Indian River Lagoon. Elevations approach five meters atop dunes bordering the beach and decrease to sea level in the mangrove swamps that are common on the western side.

The Atlantic shoreline of South 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 Gulf Stream (Florida Current), which flows parallel to the continental shelf margin, begins to diverge from the coastline at West Palm Beach. At South Hutchinson Island, the current is approximately 33 km offshore. Oceanic waters associated with the western boundary of the current periodically meander over the inner shelf, especially during summer months.

1.2 Plant Description The St. Lucie Plant consists of two 1,000 MWe nuclear-fueled electric generating units that use nearshore ocean waters for the plant's once-through condenser cooling system.

Unit 1 was placed on-line in March 1976 and Unit 2 was placed on-line in April 1983.

Water for this system enters through three submerged intake structures located 365 m offshore (Figure 2). The intake structures are equipped with a velocity cap to minimize entrainment of marine life. Water passes through these structures and into submerged intake pipes (two 3.7 m and one 4.9 m in diameter) running under the beach. It then passes into a 1,500 m long intake canal, which transports it 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 along the ocean floor to the submerged discharges, the first of which is 730 m north of the intake and extends approximately 365 m offshore. The second pipeline is located just to the south of the first and is nearly twice as long.

1.3 Environmental Reporting St. Lucie 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 7

at the site (Applied Biology, Inc. [ABI] 1978, 1980, 1986-1989, 1994 ). Jurisdiction for sea turtle studies lies with the Nuclear Regulatory Commission (NRC), which is considered to be the lead federal agency relative to consultation under the Endangered Species Act (ESA). This document has been prepared to satisfy the requirements contained in Appendix B, Environmental Protection Plan (EPP); St. Lucie Units 1 and 2 Facility Operating License Nos. DPR-67 and NPF-16. Previous results dealing with sea turtle studies are contained in 37 annual environmental operating reports covering the period from 1983 through 2022 (ABI 1984-1994; Quantum Resources, Inc. 1995-2009; I nwater Research Group, Inc. [IRG] 2010-2022). This report describes the 2023 environmental protection activities related to sea turtles as required by Subsection 4.2 of the St. Lucie Units 1 and 2 EPP. Other routine annual reporting requirements are addressed in Section

8.

2.0 Sea Turtle Nest Monitoring Sea turtle nesting typically occurs along Florida's Atlantic coast from March through September. Furthermore, South Hutchinson Island is an important rookery for loggerhead (Caretta caretta), green (Chelonia mydas), and leatherback (Dermoche/ys coriacea) turtles (Meylan, Schroeder, & Mosier, 1995). Under the ESA, the federal government has classified loggerhead and green turtles as threatened species while leatherbacks are classified as endangered. One of FPL's primary environmental concerns is to ensure the operation of the St. Lucie Plant does not adversely affect sea turtle nesting and, as such, they have sponsored monitoring of nesting activity on the island since 1971.

2.1 Methodology 2.1.1 Previous Methods & Projects Daytime nesting surveys and nighttime turtle tagging programs were conducted in odd numbered years from 1971 through 1979. During daytime nesting 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) provided baseline data for nesting activity on South Hutchinson Island. Though the plant was not operating during 1975, the St. Lucie Plant Unit 1 ocean intake and discharge structures were installed during that year. Installation of these structures included nighttime construction activities conducted offshore from and perpendicular to the beach.

The plant was in full operation during the 1977 and 1979 surveys.

A modified daytime nesting survey was conducted in 1980 during the preliminary construction of the ocean discharge structure for St. Lucie Plant Unit 2. Four of the previously established 1.25 km-long survey areas were monitored. To mitigate any 8

adverse effects associated with construction activities, turtle nests proximal to the construction area were relocated.

The St. Lucie Plant Unit 2 discharge structure was installed during the 1981 nesting season. Construction of the Unit 2 intake structure proceeded throughout the 1982 nesting season and was completed near the end of the 1983 season. Mitigation activities associated with installation of both structures were similar to those conducted when the Unit 1 intake and discharge structures were installed. Analysis 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 (ABI, 1987). However, nesting at the plant consistently returned to levels similar to or greater than those at a control site in years following the construction.

During 1991, a major offshore construction project was undertaken to replace damaged velocity caps on the three intake structures. A large, elevated platform, from which repair activities were conducted, was erected around the three structures. Construction occurred throughout the nesting season. 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 was implemented to mitigate any negative effects resulting from the required safety and navigational lighting on and near the platform. The plan included caging nests along a 1,500 m section of beach west of the platform and the release of hatchlings to unaffected areas to the north and south.

During this period, nests were more abundant at the construction site than at the control site.

Reconstruction of the primary dune in front of the plant was completed by FPL prior to the beginning of the 2005 sea turtle nesting season. This project was required due to the widespread obliteration of the primary dune during the 2004 hurricane season. Despite the compact material and erosion problems associated with the reconstructed dune, nesting success was not noticeably different from that of the unaffected survey zones to the north and south of the project area.

In 2012, FPL implemented a construction project at the discharge canal headwall where a retaining wall was added landward of the beach-facing dune. Construction activities took place on a 100 m section on the crest of the primary dune line at the eastern end of the discharge canal. Daily sea turtle nesting surveys were performed as required by the construction permit. From the beginning of nesting season until May 21, nests were left in situ. Beginning on May 22, nests that could have been impacted by construction activities were relocated to a hatchery area approximately 1 km north of the construction site.

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Another dune restoration project in front of the plant was completed by FPL prior to the beginning of the 2013 sea turtle nesting season. This project was required due to erosion of the previous dune restoration area. Sea turtle nesting surveys were again performed in conjunction with the restoration activities. Sand placement began in January and was completed by mid-February (prior to the start of sea turtle nesting season). The planting of dune vegetation was subsequently completed in March. No nests or false crawls were recorded during the project timeframe.

Dune restoration activities were repeated in 2019 precipitated by damage from Hurricane Irma (2017). Dune planting was completed in front of the power plant in April and daily sea turtle nesting surveys were performed to ensure that nests were protected.

Subsequently, the beach in front of the discharge canal was renourished after the completion of the 2019 sea turtle nesting season in December. There were no remaining nests in the project area at that time.

In 2020, FPL completed construction of a breakwater consisting of submerged modular concrete "Reef Balls" parallel to and immediately offshore from the St. Lucie site. As such, an area of the beach 5,000 ft long directly in front of the power plant was designated for intensive nest marking and productivity analysis in association with the St. Lucie Power Plant Breakwater Project (DEP Permit #0314668-001-JC). Nest marking and inventories were conducted for every nest within this "project area", an effort that is mandated by the Department of Environmental Protection (DEP) for three complete sea turtle nesting seasons following the placement of the breakwater.

In 2023, an emergency dune restoration project in front of the plant was completed by FPL due to continued erosion caused during Hurricane Nicole (2022). Sand placement began in March and was completed by mid-April. The planting of dune vegetation was subsequently completed in April. Nighttime sea turtle nesting monitoring was performed in conjunction with the restoration activities. One leatherback nest and one leatherback false crawl were reported in the project area during restoration.

2.1.2 Current Methods Nesting surveys to satisfy environmental reporting requirements were completed in 1986 (ABI, 1987) but continued voluntarily through 1998 with agreement from federal and state agencies. In 1998, the continuation of the nesting survey program was mandated as part of the Biological Opinion (BO) and Incidental Take Statement issued by the National Marine Fisheries Service (NMFS). An amendment to the EPP was approved in 1999 to include these requirements.

From 1981 through 2023, 36 one-km-long segments comprising the island's coastline have been surveyed seven days a week during the nesting season (Figure 3). These 10

"zones" are identified starting with Zone A at the northern end of the island and continue through Zone JJ at the southern end. Since the 1994 nesting season, the southern half of the island (Zone T to Zone JJ) has been surveyed by Ecological Associates, Inc. (EAi),

and their data are included in this report.

Biologists used all-terrain vehicles to survey the island each morning. New nests, non-nesting emergences (false crawls), and nests affected by predators were recorded for each zone. Data collected from beach nesting surveys were then reported to the Florida Fish and Wildlife Conservation Commission (FWC) as part of both the Index Nesting Beach Survey and the Statewide Nesting Beach Survey.

2.2 Results for 2023 In 2023, Zones E-S were surveyed by lnwater Research Group, Inc. (IRG). EAi surveyed Zones A-D as part of a beach renourishment project south of the Fort Pierce Inlet. Data from those zones, as well as the south end of South Hutchinson Island, were supplied by EAi and were used to provide whole-island nesting totals (Figures 4 - 6).

Nesting surveys were conducted every other day in March for zones A-S on South Hutchinson Island. Eleven leatherback sea turtle nests were recorded in Zones A-S prior to the beginning of daily nesting surveys on April 1. From April 1 through September 30, nest surveys were conducted daily.

Not all ventures onto the beach by a female turtle result in a successful nest. These "false crawls" (non-nesting emergences) may occur for many reasons and are commonly encountered at other rookeries. Davis and Whiting (1977) suggest that relatively high percentages of false crawls may reflect disturbances or unsatisfactory nesting beach characteristics.

Historically, the distribution of loggerhead emergences on the island has been consistent with the distribution of nests, with no difference in nesting success among zones. We can only speculate over the current causes for differences in nesting success between zones (Figure 7). Recent beach renourishment, coastal construction projects, prolonged periods of drought, formation of large escarpments that prevent turtles from crawling above the high tide line, and light pollution from inland sources may have all contributed to lower nesting success in the northernmost zones. Nesting success in the zone that includes the plant (Zone 0) was lower than surrounding zones (Figure 7) and attributed to recent beach erosion and narrow beach profile within the zone.

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2.2.1 Loggerhead Nesting Most loggerhead nesting occurs on warm temperate and subtropical beaches (Dodd, 1988) with Florida representing one of the most important loggerhead rookeries in the world (Casale & Tucker, 2017; Ceriani & Meylan, 2017). According to the FWC Fish and Wildlife Research lnstitute's Statewide Nesting Beach Survey Program, over 90,000 loggerhead nests have been deposited annually on Florida beaches for the past five years. Moreover, the beaches in southeast Florida are especially prolific nesting areas, with South Hutchinson Island being a critically important nesting beach (Meylan, Schroeder, & Mosier, 1995). Between 4,000 and 15,000 loggerhead nests have been deposited annually on South Hutchinson Island during the last 30 years (Figure 4).

In 2023, 14,360 loggerhead nests were recorded on South Hutchinson Island (Figure 4).

In Zones A-S (the north end of the island) biologists observed 5,492 nests (Figure 8). The first recorded nest was on April 19, and the last loggerhead nest was recorded on September 7. There were 10,161 loggerhead false crawls observed in Zones A-S.

To assess nest productivity, 560 of the 5,492 loggerhead nests were inventoried.

Inventories were successfully completed on 177 nests, 149 nests were completely or heavily predated, 127 nests were not inventoried due to a change in marking scheme, 51 nests could not be located again, 55 nests washed out, and one nest was too decomposed to inventory. The 177 inventoried nests contained a cumulative total of 17,431 eggs. Of these, 9,834 successfully hatched and emerged from the marked nests.

This represents an emergence success rate of 56.4%. There were also 150 live loggerhead hatchlings found during nest excavations. However, these hatchlings were not considered to have successfully emerged from the nest.

Loggerhead nesting activity on South Hutchinson Island fluctuates considerably from year to year (Figure 4). Annual variations in nest densities are also common at other rookeries, and probably result from non-annual reproductive behavior (Heppell, Snover, & Crowder, 2003). Statewide trends mirror the nesting activity seen on South Hutchinson Island with three distinct periods: increasing 1989-1998, decreasing 1998-2007, and then increasing since 2007 (Ceriani et al., 2019). No relationships between annual fluctuations in nesting activity and plant operation or intake/discharge construction have ever been found.

2.2.2 Green Nesting The green turtle is the second most common sea turtle on Florida nesting beaches.

Approximately 99% of the green turtle nesting in Florida occurs on the Atlantic coast from Brevard through Broward Counties (Witherington, Herren, Bresette, 2006). On South Hutchinson Island, green turtles have had alternating years of nesting: a high nesting year followed by a low nesting year, although this pattern has become less distinct in recent 12

years. This biennial pattern is also seen at other locations throughout their nesting range (Witherington et al., 2006).

In 2023, 2,270 green turtle nests were recorded on South Hutchinson Island (Figure 5).

Biologists observed a total of 1,068 green turtle nests in Zones A-S (Figure 8). The first recorded nest of the season was on May 15, and the last green turtle nest was noted on October 16. There were 1,993 green turtle false crawls observed in Zones A-S.

To assess nest productivity, 212 of the 1,068 green turtle nests were marked. Inventories were successfully completed on 83 nests, 55 nests were not inventoried to a change in marking scheme, 35 nests could not be located, 34 nests were completely predated, four nests washed out, and one nest occupied the same egg chamber as an incubating loggerhead nest. The 83 inventoried nests contained a cumulative total of 8,905 eggs. Of these, 4,994 successfully hatched and emerged from the marked nests. This represents an emergence success rate of 56.1 %. In addition, there were 255 live green turtles found during nest excavations. These hatchlings were not considered to have successfully emerged from the nest.

2.2.3 Leatherback Nesting Leatherback nesting occurs on subtropical and tropical beaches. They inhabit Florida waters primarily during the nesting season (March-June) and are generally found in higher densities close to shore awaiting nesting forays onto the beach (Schroeder &

Thompson, 1987). Outside of nesting season, leatherbacks are often found in pelagic habitats as far north as the Canadian Maritimes where they feed primarily on jellyfish (Fossette et al., 2010).

In 2023, 338 leatherback sea turtle nests were recorded on South Hutchinson Island (Figure 6). Biologists observed a total of 97 leatherback nests in Zones A-S (Figure 8).

The first recorded nest was on March 19, and the last leatherback nest was recorded on July 16. There were 35 leatherback sea turtle false crawls observed in the surveyed areas A-S.

To assess nest productivity, 22 of the 97 leatherback turtle nests were marked.

Inventories were successfully completed on 15 nests, six nests could not be located again, and one nest washed out. The 15 nests that were inventoried contained a cumulative total of 995 eggs. Of these, 418 successfully hatched and emerged from the marked nests unaided. This represents an emergence success rate of 42.0%. There were also 13 live leatherback turtles found during nest excavations. These hatchlings were not considered to have successfully emerged from the nest.

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Leatherback nesting on South Hutchinson Island generally mirrors the nesting trend for the entire state of Florida. Stewart et al. (2011) demonstrated that the number of leatherback nests in Florida have increased more than 10% per year between 1979 and 2011. However, over the last several years nesting numbers have been on the decline (Figure 6). Leatherback nesting numbers began to rebound in 2020 but biologists will need to continue monitoring leatherback nesting to ascertain whether this is a true trend reversal, as we do not yet have enough data to make this determination.

2.2.4 Predation Historically, raccoon (Procyon lotor) predation has been the leading cause of turtle nest destruction on South Hutchinson Island (ABI, 1989). Though turtle nests on South Hutchinson Island have probably been depreciated by ghost crabs (Ocypode quadrata) since nesting surveys began, quantification of ghost crab predation did not begin until 1983. Occasionally, sea turtle nests are depreciated by other animals such as bobcats (Lynx rufus), fire ants ( Solenopsis invicta), and various species of birds. However, this only accounts for a small portion of the total number of predation events on South Hutchinson Island.

IRG biologists recorded a total of 547 predation events for South Hutchinson Island in 2023 within beach Sections A-S (Figure 9). Sea turtle nests on South Hutchinson Island were depreciated by raccoons, ghost crabs, and fire ants. Raccoons were the most abundant predator, accounting for 331 events. The second most abundant predators were ghost crabs, which accounted for 95 individual predation events. A combination of raccoon and ghost crab predation accounted for an additional 112 predation events.

Other predators accounted for only nine predation events.

Nest excavation provides an opportunity to account for predation activity more accurately.

For example, fire ant and ghost crab predation are not always evident from a cursory inspection of the sea turtle nest's surface. Predators impacted 29.1 % of nests (80 out of 275) where hatch success could be evaluated.

2.2.5 Poaching EAi documented four human disturbances in 2023, south of the Fort Pierce Inlet (Zones A-D). For two disturbances there was evidence of humans digging into marked loggerhead nests, but the egg chambers were not breached. In one instance, a human dug into a marked loggerhead nest and actively took hatchlings from the nest. For one disturbance, a human spray painted the sand at the clutch location with blue paint, as well as the stake marking the toe of the dune. For all four disturbances, FWC law enforcement was notified.

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3.0 Intake Canal Monitoring 3.1 Barrier Nets There are three barrier nets that stretch across the entire width of the intake canal; they are the primary 5-inch, 8-inch A-1-A, and 10-inch Underwater Intrusion Detection System (UIDS Barrier; Figure 2). These barrier nets serve to constrain the movement of turtles to facilitate capture and also help prevent the entrainment of debris from interfering with the availability of clean cooling water for the power plant.

Maintaining the integrity of the barrier nets is essential to reducing mortality rates and residency times of entrained sea turtles and is mandated by the most recent BO issued by NMFS. Daily inspections are performed from a small boat to remove floating debris and to repair holes at or near the water's surface. Periodic inspections of the barrier nets, as well as cleaning debris when warranted, are conducted by Underwater Engineering Services, Inc. (UESI).

In addition to scheduled inspections and cleaning of the nets, divers are deployed when the integrity of the nets are threatened by algae events. These algae events can cause undue stress to the net structures and may cause the nets to fail. Net failures increase both the risk of sea turtle mortalities and overall residency times. Turtles can become tangled in or pinned under a failed barrier net, leading to a causal drowning mortality.

Furthermore, if turtles have access to larger portions of the intake canal, it then becomes more challenging to quickly capture and release these animals back into their natural environment. The primary barrier net, with few exceptions, has effectively confined sea turtles to the eastern 200 meters of the intake canal.

3.1.1 Background In 1978, a barrier net at the A 1A bridge (Figure 2) was constructed to confine turtles to the easternmost section of the intake 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's surface and the bottom of the net is anchored by a series of concrete blocks. The net is inclined at a slope of 1: 1, with the bottom positioned upstream of the surface cable. This reduces bowing in the center and minimizes the risk of a weak or injured turtle being pinned underwater by strong currents.

In the past, the integrity of the barrier net was occasionally compromised, and turtles were able to move west of A 1 A. These turtles were further constrained downstream by a proprietary UIDS net consisting, in part, of a large barrier positioned perpendicular to the north-south arm of the canal (Figure 2). The UIDS security barrier has a mesh size of 15

22.9 cm x 22.9 cm. Prior to completion of the UIDS in December 1986, turtles unconfined by the A 1A barrier net were usually removed from the canal at the intake wells of Units 1 and 2 (Figure 2) with specially designed nets. Following construction of the UIDS barrier, only the smallest individuals were able to reach the intake wells. Improvements made to the A 1A barrier net in 1990 have effectively confined all turtles larger than 32.5 cm carapace length (28.7 cm carapace width) to the eastern end of the canal.

In January 1996 (in response to the large numbers of small green turtles entrained in the intake canal in the early 1990s), an improved barrier net design involving a smaller 12.7 x 12.7 cm mesh size was erected 150 m east of A1A (Figure 2). This additional "primary barrier net" was designed to confine all turtles with a carapace width greater than 18 cm to the extreme eastern portion of the intake canal. However, the integrity of this net was often compromised by incursions of seaweed, drift algae, jellyfish, and siltation. During these events, water velocities around the net increased dramatically creating an insufficient net slope that caused several sea turtle mortalities. To address this design problem and to further alleviate mortalities, FPL constructed a new net with a stronger mesh and added support structures. Dredging of the canal east of the A 1A net was also conducted to minimize water velocities around the new barrier net. All construction was completed by November 2002.

In October 2009, the primary barrier net and support structures failed due to an algae event, submerging the north half of the net 0.6-1.5 m underwater (IRG, 2010). UESI installed large floating buoys onto the primary net to create a temporary barrier. However, this temporary barrier net was found to be susceptible to partial submergence or failure due to severe algae/jellyfish events or at extreme high tides. Therefore, construction on a new permanent primary barrier net began in 2014 and was completed in January 2015.

In September 2017, Hurricane Irma led to the failure of both the primary and secondary barrier nets. The heavily damaged 8-inch A-1-A net was replaced immediately after the storm and the primary 5-inch net was replaced February 9, 2018.

In February 2019, several juvenile green turtles were removed from the intake wells. In response, UESI inspected the primary 5-inch barrier net and discovered that there were gaps along the bottom of the net. The uneven accumulation of sediment along the base of the barrier net had exerted significant pressure on the net and altered its configuration.

Under the direction of FPL, UESI repaired and then retensioned the primary barrier to improve its overall performance.

In April 2019, Ballard Marine Construction began dredging the intake canal to remove sediment buildup and ensure proper flow rates in the intake canal system. The secondary 8-inch barrier net was temporarily removed to facilitate this process prior to its successful completion in August 2019.

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In March 2022, UESI replaced the primary 5-inch net. The previous net exhibited signs of degradation and therefore was replaced and retensioned. The new net has performed as designed since installation.

3.1.2 Current Methods & Results Presently, the 5-inch and 8-inch barrier nets are inspected quarterly and the 10-inch UIDS net is inspected semiannually. In May and December 2023, UESI repaired small holes in the primary 5-inch barrier net.

3.2 Intake Pipe Cleaning & Maintenance Beginning in 2002, there was a steady increase in the number of sea turtles incurring scrapes during transit through the power plant intake pipes (the three large diameter pipes that initially bring water into the intake canal system from offshore). These scrapes varied in degree of severity, with most being minor and similar to those found on sea turtles that inhabit nearshore reefs. However, some scrapes were moderate or severe, causing some turtles to be sent to rehabilitation facilities for treatment. This prompted FPL to inspect the intake pipes in 2006 and schedule the cleaning of bio-fouling and marine debris that were thought to be causing the scrapes to entrained sea turtles.

Cleaning and removal of debris from the intake pipes and offshore intake structures began in October 2007 and were completed in February 2011. Additionally, two openings that extended from the top of the two 12-foot intake pipes were also sealed off during this time.

3.3 Power Plant Outages Decreased water flow during power plant outages likely reduces the number of turtles entrained into the intake canal. An outage occurs when the power generating unit is offline. There was one short-term power plant outage in 2023. Unit 2 was in outage from February 18 until March 18.

4.0 Intake Canal Captures 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 (Ecological Associates, Inc., 2000). The velocity caps, which are 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 a wider area. Even when both units are operating at full capacity, turtles must actively swim into the mouth of one of the structures before they encounter 17

current velocities sufficient enough to entrain them. 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 entrained in the intake canal have been systematically captured, measured, weighed, tagged, and released.

4.1 Methodology 4.1.1 Turtle Capture Historically, most turtles entrained in the St. Lucie Plant intake canal were removed using large-mesh tangle nets set near the intake canal headwalls at the extreme eastern end of the intake canal (Figure 2). Nets used were from 30 to 40 m in length, 3 to 4 m deep, and composed of 40 cm stretch mesh multifilament nylon. Large floats were attached to the surface and unweighted lines were used along the bottom. Turtles entangled in the nets generally remained at the water's surface until removed. Nets were usually deployed on Monday morning and retrieved on Friday afternoon. During periods of deployment, the nets were inspected for captures at least twice each day (mornings and afternoons). St.

Lucie Plant personnel checked the nets periodically and biologists were notified immediately if a capture was observed. 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 intake canal system.

Beginning in April 1990, after consultation with NMFS, net deployment was scaled back to daylight hours only. Concurrently, surveillance of the intake canal was increased, and biologists remained on site for the duration of each day's netting activities. This measure decreased response time for removal of entangled turtles and provided an opportunity to improve daily assessments of turtle abundance within the canal.

During each day's directed capture efforts, formal inspections of the intake canal were made to determine the number, location, and species of turtles present. Surface observations were augmented with periodic underwater inspections, particularly in and around the barrier nets. These observations allowed for a rough estimate of how many sea turtles were in each section of the canal on a given day.

The canal capture program has been under continual review and refinement to minimize both entanglement time and injuries/mortalities to sea turtles. Better utilization of currents and eddies, adjustments to tethering lines, multi-net deployments, and increased efforts to hand capture and dip net turtles have contributed to reduced residency times in recent years.

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4.1.2 Data Collection Regardless of capture method, all turtles removed from the canal are identified to species, measured, weighed, tagged with external flipper tags, and given a basic health assessment (noting body condition, any wounds, abnormalities, parasites, etc.). Since 1994, captured turtles have also been photographed dorsally and ventrally prior to release. Additionally, as of July 2001, Passive Integrated Transponder (PIT) tags are injected subcutaneously into the right front flipper. Healthy turtles are released into the ocean the same day of capture. When treatment is warranted, turtles are transported to an approved rehabilitation facility after consultation with FWC. Beginning in 1982, necropsies were conducted on dead turtles found in fresh condition. Currently, fresh dead turtles are held on ice and taken to a qualified veterinarian for necropsy. Methodologies associated with the canal capture program have remained essentially unchanged since 1994, making data comparable from that year through the current reporting period.

4.2 Results for 2023 Methods to remove sea turtles from the intake canal include the use of tangle nets, dip nets, and hand capture methods. Long-handled dip nets employed from small boats, the canal banks, and headwall structures are moderately effective in capturing turtles with carapace lengths of 40 cm or less. Snorkelers are also employed to hand capture turtles whenever water visibility permits. This technique has proven highly effective in the capture of turtles of all sizes, particularly less active individuals that are often found partially buried in the sediment near the primary barrier net. Moreover, proactive capture methods (hand capture and dip net) consistently reduce residency times for turtles in the intake canal.

During 2023, a total of 921 sea turtles were removed from the intake canal, including 355 loggerheads, 557 green turtles, four Kemp's ridleys, two leatherbacks, two hawksbills, and one olive ridley. (Figures 10 & 11; Table 1). The majority of these turtles (97.7%)

were captured alive and released back to the ocean. Twenty (2.2%) turtles were taken to rehabilitation facilities for treatment of injuries or disease, and one (0.1 %) turtle was dead.

Specifically, ten loggerheads and ten green turtles were sent to rehabilitation facilities for non-causal injuries. Additionally, there was one causal injury and one causal mortality (both green turtles).

In 2023, 921 turtles were captured east of the primary barrier net-713 by tangle nets, 24 by hand capture, 172 by dip net, and 12 off the primary barrier net. Proactive captures accounted for 21.3% of the turtles removed from the intake canal.

Three loggerheads and three greens nested on the canal banks during the 2023 sea turtle nesting season. The nests were relocated and later excavated to determine hatch 19

success in accordance with FWC protocols. The last intake canal nests were documented in 2019, 2021, and 2022.

4.2.1 Loggerhead Captures Historically, loggerheads have been the most abundant species entrained into the canal.

The number of loggerheads captured each year ranged from 62 in 1981 to 623 in 2004 (Table 1 ). During 2023, monthly captures of loggerheads ranged from three in March to 102 in June (Table 2), with a monthly mean of 30. Loggerhead capture rates have exhibited considerable year-to-year fluctuations but have shown an overall increasing trend between the time the power plant started operation through the early 2000's (Figure 1 O; Table 1 ). Since this time, the loggerhead capture rates have tapered off somewhat but have remained relatively stable. The size frequency of loggerheads ranges from predominately juvenile to sub-adult animals, with adult animals captured mainly during the nesting season of April through September (Figure 12).

Of the 355 loggerheads captured in 2023, 58 were juveniles (Straight Standard Carapace Length; SSCL < 70 cm), 143 were transitional (SSCL 70-84.9 cm), and 154 were adults (SSCL ~ 85 cm; Hirth, 1980; Figure 12). The intermediate group likely includes both mature and immature individuals. Of the 158 turtles classified as adults, 144 were females and 11 were males. Three additional loggerheads were recorded as male, even though their SSCL was less than 85 cm, because sex was apparent from the animal's tail length (Owens 1997). In addition, there was one loggerhead in the intermediate size class that was classified as female because it was discovered attempting to nest after its release.

4.2.2 Green Captures The number of green turtles captured each year has ranged from three in 1979 to a record high of 673 in 1995 (Figure 1 O; Table 1 ). A spike in green turtle captures, driven mainly by small juveniles (Bresette, Gorham, & Peery, 1998) during the mid-1990s, has leveled off to a capture rate consistently greater than numbers recorded prior to 1994. Size-class frequencies of green turtles at the intake canal are dominated by juvenile animals with adults captured in relatively small numbers during the nesting season of May through October (Figure 13).

During 2023, monthly green turtle captures ranged from six in July to 93 in both May and December (Table 2), with a monthly mean of 46. Of the 557 green turtles captured in 2023, there were 415 juveniles or sub-adults (SSCL < 85 cm) and 142 adults (Witherington and Ehrhart, 1989; Figure 13). Of the 142 turtles classified as adults, 68 were female, and 74 were male.

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4.2.3 Leatherback, Hawksbill, Kemp's, & Olive Ridley Captures Captures of leatherback, hawksbill, and Kemp's ridley turtles have been infrequent and scattered throughout the years (Figure 11; Table 1 ). However, each species has shown rather pronounced seasonal occurrences (Table 3). Leatherbacks are typically captured in March and April, hawksbills are captured between July and September, and Kemp's ridleys are caught between December and April. Previously, only one olive ridley had ever been captured at the St. Lucie site and it was encountered in May 2019.

In 2023, there were four Kemp's ridleys, two hawksbills, two leatherbacks, and one olive ridley captured in the intake canal of the St. Lucie Plant (Table 1 ). The Kemp's ridleys were sub-adults (SSCL ranged from 51. 7 cm to 57.2 cm). The leatherbacks were adult females (SSCL 129.5 cm and 133.6 cm; Stewart et al., 2007). The hawksbills included one adult female and one sub-adult (SSCL 68.5 cm and 78.4 cm; Meylan and Redlow, 2006). The olive ridley was an adult female with an SSCL of 65.6 cm (Zug, Chaloupka, &

Balazs, 2006). This is only the second olive ridley ever captured at the St. Lucie Power Plant.

4.2.4 Recaptures Since plant operation began in 1976, a total of 20,220 sea turtles (including recaptures) have been captured, including 11,356 loggerheads, 8,631 green turtles, 110 Kemp's ridleys, 74 hawksbills, 47 leatherbacks, and two olive ridleys (Table 1).

Most turtles removed from the intake canal have been tagged and released into the ocean at various locations along South Hutchinson Island. Individual turtles can be identified as long as they retain their tags. Over the history of the program at the St. Lucie Plant, 3,643 recapture events (879 loggerheads, 2,763 green turtles, and one Kemp's ridley) have occurred. The recapture rate in 2023 was 12.1 % for loggerheads and 24.8% for green turtles.

Occasionally, turtles are captured that have been tagged by other researchers; there were 14 such captures in 2023.

A female loggerhead was originally tagged by UCF researchers in 2010. A female loggerhead was originally tagged by Loggerhead Marinelife Center while nesting on Juno Beach in 2021. A female loggerhead was originally tagged by UCF researchers while nesting on Archie Carr National Wildlife Refuge in 2018. A male loggerhead was originally tagged by I RG during a separate research project near Jennings Cove, FL in 2006. A sub-adult loggerhead was originally tagged by NOAA/FWC in Florida Bay in 2005. A sub-adult loggerhead was originally tagged by IRG during a separate research project in Key West National Wildlife Refuge in 2012. A sub-adult loggerhead was originally tagged by 21

UCF in the Indian River Lagoon in 2015. A sub-adult loggerhead was originally rehabilitated, tagged, and released in 2020 by Brevard Zoo. A sub-adult loggerhead was originally rehabilitated, tagged, and released in 2020 by Brevard Zoo in 2022. A female green was originally tagged by UCF researchers in the Indian River Lagoon in 2004. A female green was originally tagged by UCF researchers while nesting on Archie Carr National Wildlife Refuge in 2019. A female green was originally tagged by UCF researchers in 2015. A male green was originally rehabilitated, tagged, and released in 2010 by Loggerhead Marinelife Center. Tagging information for a juvenile green turtle is pending.

4.2.5 Relative Condition Turtles captured alive in the intake canal of the St. Lucie Plant are assigned a relative condition based on weight, activity, parasite jnfestation, epibiont coverage, injuries, and any other abnormalities that might affect overall vitality. Relative condition ratings can be influenced by several factors, some related and others unrelated to entrainment into the intake canal. A rating of good indicates that turtles have not been negatively impacted by their entrapment in the canal, as evidenced by physical appearance. Although ratings of fair or poor imply reduced vitality, the extent to which entrainment and entrapment are responsible is often indeterminable. In some instances, acute injuries responsible for lower overall condition ratings, such as boat collision, fisheries gear entanglement, or disease were obviously sustained prior to entrainment. However, in recent years, turtles have been found with fresh scrapes and cuts incurred during the entrainment process.

Some of these incidents have had a negative effect on a sea turtle's overall condition and have been categorized as directly causal to plant operation. Causal determinations are made by consultation with personnel from FWC and/or a qualified veterinarian.

During 2023, of the 355 loggerheads captured, 95.2% (338) were alive and in good condition. Only 4.8% (17) of all loggerheads were in fair or poor condition and no turtles were recovered postmortem. Of the 557 green turtles removed from the intake canal, 97.7% (544) were in good condition, and 2.3% (13) were in fair or poor condition.

Since the 2016 Biological Opinion, FPL has been required to record the number of captured turtles with fresh scrapes caused by entrainment and categorize them as either minor, moderate, or severe. A severe fresh scrape is an injury that would generally require medical consultation and/or rehabilitation. Furthermore, the BO dictates that if the number of turtles with severe fresh scrapes reaches 0.5% of the number of captured turtles or if the number of turtles with moderate or severe fresh scrapes reaches 15% of the number of captured turtles during two consecutive years, FPL shall start the process for inspecting the intake pipes and evaluate and initiate corrective action within one month.

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Of the 921 turtles removed from the intake canal during the year, 851 were observed with fresh cuts or scrapes that may have been incurred during transit through the intake pipes.

Although these scrapes varied in degree of severity, most turtles were classified as having either none or only minor fresh scrapes (96.3%). No turtles were found with severe fresh scrapes this past year. However, 34 turtles had moderate fresh scrapes. Consequently,

3. 7% of turtles were categorized as having either moderate or severe fresh scrapes.

Moreover, both percentages were below the threshold required for action under the most recent BO.

4.2.6 Mortalities & Injuries Injuries and mortalities are categorized in two ways - causal to plant operation or non-causal to plant operation. These decisions are made in consultation with FWC and/or a qualified veterinarian. Not all mortalities and injuries are causal to plant operation as some sea turtles enter the canal in either a moribund state or have had pre-existing conditions related to fisheries, boat interactions, or disease. Injuries and mortalities causal to plant operation are recorded and applied against the take limit established by the most recent BO set forth by NMFS.

Sea turtle mortalities have been closely monitored throughout the history of the capture program in an attempt to assign probable cause and take remedial action to minimize future occurrences. Modifications to capture procedures, improvements to barrier nets, and virtual elimination of low flow conditions within the intake pipes have resulted in a substantial reduction in sea turtle mortalities over the life of the canal capture program.

The mortality rate declined from 7.9% during the period 1976-1984 to 1.3% for the period 1985 to present (Table 1 ). Over the entire monitoring program's history (1976-2022), 189 (1.7%) loggerheads and 140 (1.6%) green turtles entrained in the canal were dead. Five Kemp's ridley mortalities have been documented at the St. Lucie Plant (two each in 1987 and 1988, and one in 2022). The only hawksbill mortality was recorded in 2014, and there have been no leatherback mortalities in the history of the project.

In 2023, one sea turtle injury was recorded at the St. Lucie plant intake canal and was considered causal to plant operations.

On June 11, an adult female green was found with a 20 cm crack along the anterior carapace that was through bone tissue. This injury was old and reopened during entrainment and therefore was classified as causal.

In 2023, one sea turtle mortality was recorded at the St. Lucie plant intake canal and was considered causal to plant operations.

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On December 5, a juvenile green turtle was found in distress while entangled in the south tangle net. After consultation with the veterinarian, the turtle was held overnight for observation, however the turtle subsequently died. In accordance with protocol, it was taken for necropsy and causality determination in accordance with stranding protocols.

This turtle was determined to have drowned and was therefore deemed causal.

4.2.7 Intake Canal Nesting FPL's contracted biologists inspect the banks of the intake canal east of the 5-inch mesh barrier net for turtle tracks or other signs of nesting each morning during nesting season (March 1st -October 31st). On May 10, a loggerhead was found to have nested on the intake canal bank overnight. On May 27, a loggerhead was found to have nested on the intake canal bank overnight. On May 29, a loggerhead was found to have nested on the intake canal bank overnight. On June 12, a green was found to have nested on the intake canal bank overnight. On June 21, a green was found to have nested on the intake canal bank in the afternoon. On June 22, a green was found to have nested on the intake canal bank overnight. FWC was promptly notified after the discovery of each nest and the nests were relocated to the beach. These nests were marked and inventoried to determine hatch success in accordance with FWC protocols.

A total of 686 eggs were relocated to the beach adjacent to the intake canal. One loggerhead and one green turtle nest were successfully inventoried, and four nests were completely predated. None of the 71 eggs in the loggerhead nest hatched. Of the 138 eggs in the green turtle nest, 108 successfully hatched and emerged from the marked nests unaided. This represents an emergence success rate of 78.3%. There were also four live green turtles found during nest excavations. These hatchlings were not considered to have successfully emerged from the nest.

FWC was furnished with an official Relocated Nest Success Report, as well as a Statewide Nesting Beach Survey for this nest, after the completion of the 2023 sea turtle nesting season.

4.2.8 Smalltooth Sawfish and Giant Manta Ray Captures One smalltooth sawfish (Pristis pectinata) was removed from the St. Lucie Plant intake canal in 2023. Additional resources from IRG, FPL, and Harbor Branch Oceanographic Institute (HBOI) were called in to assist. Release was performed according to the Smalltooth Sawfish Handling, Transportation, and Release Protocols (FPL 2007) and recent smalltooth sawfish on-site training (2016). Tissue samples were collected, and tags applied by HBOI biologists under NMFS permit 25864.

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This capture occurred on January 5, 2023. The sawfish was in good condition with only minor fresh scrapes. The fish was a 3.87 m female weighing approximately 150 kg. It was successfully released into the ocean adjacent to the intake canal beach access. IRG biologists continued to monitor the three-mile stretch of beach along Hutchinson Island following the release for any possible delayed impacts on the captured smalltooth sawfish for seven days. There was no indication that the animal stranded, and it is presumed to still be living offshore.

The Incidental Take Limit established by the 2022 Biological Opinion is three non-lethal captures of U.S. Distinct Population Segment smalltooth sawfish (Pristis pectinata) during a three-year period (2022 - 2024).

No giant manta rays were encountered in the St. Lucie Plant intake canal in 2023. The Incidental Take Limit established by the 2022 Biological Opinion is three non-lethal captures giant manta rays (Mobula birostris) during a three-year period (2022 - 2024).

5.0 Sea Turtle Protective Activities 5.1 NMFS Section 7 Consultations In accordance with Section 7 of the ESA, FPL must submit a Biological Assessment to NMFS for review if FPL exceeds the Incidental Take Limit established by the most recent BO. The BO is an analytical document that looks at the effects of a federal action on endangered and threatened species.

Section 7(b) (4) of the ESA refers to the incidental take of listed species. It sets forth the requirements when a proposed agency action is found to be consistent with Section 7(a)

(2) of the ESA and the proposed action may incidentally take listed species. NMFS is responsible for issuing a statement that specifies the impact of any incidental take of endangered or threatened species. It also states that reasonable and prudent measures, and terms and conditions to implement the measures, be provided to minimize such impacts.

In 1999, FPL exceeded their anticipated incidental take limit established by the 1997 BO set forth by NMFS. This required reinitiating consultation under Section 7 of the ESA. As part of this consultation, FPL conducted a study on the factors influencing sea turtle entrainment (EAi, 2000). NMFS considered this information when developing the new BO that was issued on May 4, 2001.

In the 2001 BO, there were several changes, most importantly in the Incidental Take Statement. It stated that FPL would exceed their take limits for a calendar year if any of the following occur: 1) more than 1000 sea turtles are captured, 2) more than 1 % of the 25

total number of loggerhead and green turtles (combined) are injured/killed due to plant operation, 3) more than two Kemp's ridley sea turtles are injured/killed due to plant operation, or 4) if any hawksbill or leatherback sea turtles are injured/killed due to plant operation. In the case where 1 % of the combined loggerhead and green turtle captures is not a whole number, it is rounded up (e.g. 520 combined captures = take limit of 6).

Under Section 7 of the Endangered Species Act, a new consultation with NMFS is required if FPL meets or exceeds the take limits specified in the Incidental Take Statement.

In 2006, FPL exceeded their sea turtle take limit at the St. Lucie Plant and reinitiated Section 7 consultation. FPL identified the contributing factors that led to exceeding the take limit in 2006 and responded by cleaning the intake pipes and other compensatory measures.

The St. Lucie Plant continued to operate under the 2001 BO until NMFS issued a new BO in March 2016. The most significant change in the new BO was to the Incidental Take Statement. It stated that FPL would exceed its take limit if: 1) more than 623 loggerheads, 500 green turtle, seven hawksbills, eight Kemp's ridleys, or five leatherbacks are captured annually; 2) more than seven green turtles or three loggerheads are documented with severe causal injuries annually; 3) more than five green turtles or three loggerhead are documented as causal mortalities annually; 4) more than one hawksbill, Kemp's ridley, or leatherback are documented with either a severe causal injury or is a causal mortality every two years; 5) more than one smalltooth sawfish is captured every five years or any smalltooth sawfish are ever killed.

After 2016 BO was issued, FPL encountered three smalltooth sawfish (two in 2017 and one in 2019) in the intake canal of the St. Lucie site. Although the fish were in good condition and promptly released, FPL exceeded its take limit, and a Section 7 consultation was reinitiated. Also, in 2018, FPL exceeded its take of causal green turtle mortalities.

Then, in both 2018 and 2019, FPL exceeded its take limit because more Kemp's ridleys were captured than allowed (no more than eight can be encountered in any given year as stipulated in the Incidental Take Statement). FPL and the NRC then reinitiated section 7 consultations with NMFS.

The new BO was issued in August 2022. The previous BO set annual limits on incidental take at the St Lucie plant. Annual take estimates of the affected species can have variability because of natural and anthropogenic factors. NMFS, based on fisheries experience, believed a 3-year period (Table 4) was more appropriate for setting take limits while reducing the likelihood of requiring reinitiation of ESA Section 7 consultation unnecessarily.

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During 2023, there were 355 loggerheads, 557 green turtles, four Kemp's ridleys, two hawksbills, two leatherbacks, and one olive ridley captured. There was one causal mortality (one green turtle) and one causal injury (one green turtle). No hawksbill, Kemp's ridley, leatherback, loggerhead, or olive ridley turtles were injured or killed. One smalltooth sawfish was captured and no manta rays were encountered in the intake canal.

Therefore, FPL has not exceeded the take limit for the 2022 - 2024 time period under the latest BO issued by NMFS (Table 4).

5.2 Sea Turtle Stranding & Salvage Network and Turtle Walks An amendment to the EPP, Requirement 4.2.1 of the St. Lucie Unit 2 operating license Appendix B, was approved in 1999. This mandated that participation in the Sea Turtle Stranding and Salvage Network (STSSN) and Public Service Turtle Walks was to become part of the BO and Incidental Take Statement issued by NMFS.

As participants in the STSSN, IRG's sea turtle biologists routinely respond to sea turtle strandings in St. Lucie and Martin Counties. This activity involves the collection of information on turtles that are found dead, debilitated, or that have been impacted by human-related activities. All permit holders participating in this program are required to complete a STSSN stranding report for each dead or debilitated turtle encountered.

Completed stranding reports are then sent to FWC.

Sea turtle nesting walks are conducted by FPL as part of their public outreach programs during the summer sea turtle nesting season. These turtle walks educate the public about relevant sea turtle protection issues and, in most cases, allow the public to view a nesting loggerhead sea turtle.

5.2.1 Results for 2023 During 2023, IRG biologists responded to 12 stranding events (one loggerhead and 11 green) in St. Lucie County. One live turtle was transported to a rehabilitation facility. The remaining 11 turtles were found dead in various stages of decomposition. The probable cause of stranding included three boat strikes, two with severe papillomatosis, one fisheries interaction, and one post-hatchling washback. The remaining five turtles were either too decomposed, had injuries of unknown origin, or otherwise lacked any salient wounds or abnormalities to indicate a probable cause of death.

During 2023, IRG biologists responded to two stranding events (two green) in Martin County. Both turtles were found dead in various stages of decomposition. The probable cause of stranding included one with severe papillomatosis. The other remaining turtle was either too decomposed, had injuries of unknown origin, or otherwise lacked any salient wounds or abnormalities to indicate a probable cause of death.

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FPL conducted 12 turtle walks between June 2 and July 8, 2023. During these programs, a total of 237 people attended, and on nine out of the 12 turtle walks participants were able to view a nesting female loggerhead turtle.

5.3 Collaborative Efforts IRG biologists continue to assist other sea turtle researchers, universities, nonprofit organizations, and state and federal agencies by providing data, specimens, and public outreach. IRG biologists at the St. Lucie Plant continued to collaborate with other researchers on seven research projects in 2023.

IRG biologists continued to work with collaborators on multiyear projects. Unhatched eggs were collected from loggerhead nests for stable isotope analysis by the Florida Fish and Wildlife Research Institute. A Ph.D. student from Arizona State University continued to utilize the large flow-through experimental testing tank at the St. Lucie site to study the behavioral responses of sea turtles to different technologies that may help keep them away from anthropogenic hazards such as fishing gear. IRG biologists collected blood samples for researchers from Loggerhead Marinelife Center (LMC) studying fibropapillomatosis in loggerhead turtles. Cloaca swabs were collected for a Florida Atlantic University (FAU) graduate student examining antibiotic resistance in the microbiome of sea turtles. Juvenile green turtles were scanned with a metal detector as part of a FAU graduate student project examining the effectiveness of the devices to find ingested fishing hooks.

In 2023, IRG biologists also assisted University of Central Florida researchers to satellite tags to male green turtles entrained in the intake canal. Blood samples from loggerhead and green turtles were collected for a FAU honors thesis student investigating sea turtle immune function.

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6.0 References Applied Biology, Inc. (1978). Ecological Monitoring at the Florida Power & Light Company, St. Lucie Plant, Annual Report 1977, Volumes I and II (AB-101).

Prepared by Applied Biology, Inc. for Florida Power & Light Company, Miami.

Applied Biology, Inc. (1980). Florida Power & Light Company, St. Lucie Plant Annual Non-Radiological Environmental Monitoring Report 1979, Volumes II and Ill, Biotic Monitoring (AB-244). Prepared by Applied Biology, Inc. for Florida Power &

Light Company, Miami.

Applied Biology, Inc. (1984). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Report 1983 (AB-533). Prepared by Applied Biology, Inc. for Florida Power & Light Company, Juno Beach.

Applied Biology, Inc. (1985). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Report 1984. Prepared by Applied Biology, Inc. for Florida Power & Light Company, Juno Beach.

Applied Biology, Inc. (1986). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Report 1985 (AB-563). Prepared by Applied Biology, Inc. for Florida Power & Light Company, Juno Beach.

Applied Biology, Inc. (1987). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Report 1986 (AB-579). Prepared by Applied Biology, Inc. for Florida Power & Light Company, Juno Beach.

Applied Biology, Inc. (1988). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Report 1987 (AB-595). Prepared by Applied Biology, Inc. for Florida Power & Light Company, Juno Beach.

Applied Biology, Inc. (1989). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Report 1988 (AB-596). Prepared by Applied Biology, Inc. for Florida Power & Light Company, Juno Beach.

Applied Biology, Inc. (1990). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Report 1989). Prepared by Applied Biology, Inc. for Florida Power & Light Company, Juno Beach.

Applied Biology, Inc. (1991 ). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Report 1990 (AB-610). Prepared by Applied Biology, Inc. for Florida Power & Light Company, Juno Beach.

Applied Biology, Inc. (1992). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Report 1991 (AB-617). Prepared by Applied Biology, Inc. for Florida Power & Light Company, Juno Beach.

Applied Biology, Inc. (1993). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Report 1992 (AB-623). Prepared by Applied Biology, Inc. for Florida Power & Light Company, Juno Beach.

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Applied Biology, Inc. (1994). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 1993 (AB-631). Prepared by Applied Biology, Inc., for Florida Power & Light Company, Juno Beach.

Bresette, M., Gorham, J., & Peery, B. (1998). Site fidelity and size frequencies of juvenile green turtles (Chelonia mydas) utilizing nearshore reefs in St. Lucie County, Florida. Marine Turlle Newsletter, 82, 5-7.

Casale, P. & Tucker, AD. (2017). Caretta (amended version of 2015 assessment). The IUCN Red List of Threatened Species 2017: e.T3897 A 119333622.

https://dx.doi.org/10.2305/IUCN.UK.2017 2.RLTS.T3897A119333622.en. Downloaded on 19 January 2021.

Ceriani, S. A, Casale, P., Brost, M., Leone, E. H., and Witherington, B.

E. (2019). Conservation implications of sea turtle nesting trends: elusive recovery of a globally important loggerhead population. Ecosphere 10 (11):

e02936.10.1002/ecs2.2936 Ceriani, S.A & Meylan, AB. (2017). Caretta caretta (Norlh West Atlantic subpopulation) (amended version of 2015 assessment). The IUCN Red List of Threatened Species 2017: e.T84131194A119339029. https://dx.doi.org/10.2305/

IUCN.UK.2017-2.RLTS.T84131194A119339029.en. Downloaded on 19 January 2021.

Davis, G.E., & Whiting, M.C. (1977). Loggerhead sea turtle nesting in Everglades National Park, Florida, USA, Herpetologica, 33, 18-28.

Dodd, C.K., Jr. (1988). Synopsis of the biological data on the loggerhead sea turlle Caretta caretta (Unnaeus1758). U.S. Fish and Wildlife Service Biological Report 88(14).

Ecological Associates, Inc. (2000). Physical and Ecological Factors Influencing Sea Turlle Entrainment Levels at the St. Lucie Power Plant 1976-1998. Submitted to FPL.

Fossette, S., Hobson, V.J., Girard, C., Calmettes, B., Gaspar, P., Georges, J., & Hays, G.C. (2010). Spatio-temporal foraging patterns of a giant zooplanktivore, the leatherback turtle. Journal of Marine Systems, 81, 225-234.

Heppel, S.S., Snover, M.L., & Crowder, L.B. (2003). Sea Turtle Population Ecology. In P. L. Lutz, J. A Musick, & J. Wyneken (Eds.), Biology of Sea Turtles Volume II (pp. 275-306).

Hirth, H.F. (1980). Some aspects of the nesting behavior and reproductive biology of sea turtles, American Zoologist, 20, 507-523.

lnwater Research Group, Inc. (2010). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 2009. Prepared by lnwater Research Group, Inc. for Florida Power & Light Company, Juno Beach, FL.

30

lnwater Research Group, Inc. (2011). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 2010. Prepared by lnwater Research Group, Inc. for Florida Power & Light Company, Juno Beach, FL.

lnwater Research Group, Inc. (2012). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 2011. Prepared by lnwater Research Group, Inc. for Florida Power & Light Company, Juno Beach, FL.

lnwater Research Group, Inc. (2013). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 2012. Prepared by lnwater Research Group, Inc. for Florida Power & Light Company, Juno Beach, FL.

lnwater Research Group, Inc. (2014). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 2013. Prepared by lnwater Research Group, Inc. for Florida Power & Light Company, Juno Beach, FL.

lnwater Research Group, Inc. (2015). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 2014. Prepared by lnwater Research Group, Inc. for Florida Power & Light Company, Juno Beach, FL.

lnwater Research Group, Inc. (2016). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 2015. Prepared by lnwater Research Group, Inc. for Florida Power & Light Company, Juno Beach, FL.

lnwater Research Group, Inc. (2017). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 2016. Prepared by lnwater Research Group, Inc. for Florida Power & Light Company, Juno Beach, FL.

lnwater Research Group, Inc. (2018). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 2017. Prepared by lnwater Research Group, Inc. for Florida Power & Light Company, Juno Beach, FL.

lnwater Research Group, Inc. (2019). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 2018. Prepared by lnwater Research Group, Inc. for Florida Power & Light Company, Juno Beach, FL.

lnwater Research Group, Inc. (2020). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 2019. Prepared by lnwater Research Group, Inc. for Florida Power & Light Company, Juno Beach, FL.

lnwater Research Group, Inc. (2021 ). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 2020. Prepared by lnwater Research Group, Inc. for Florida Power & Light Company, Juno Beach, FL.

lnwater Research Group, Inc. (2022). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 2021. Prepared by lnwater Research Group, Inc. for Florida Power & Light Company, Juno Beach, FL.

Meylan, A.B., Schroeder, B. & Mosier, A. (1995), Sea turtle nesting activity in the state of Florida, 1979-1992. Florida Marine Research Publications, 52, 1-51.

31

Meylan, A., and A. Redlow. 2006. Eretmochelys imbricata - Hawksbill Turtle. Pp. 105-127 In Biology and Conservation of Florida Turtles. Meylan, P.A. (Ed.). Chelonian Research Monographs No. 3.

Owens, D. (1997) Hormones in the Life History of Sea Turtles. In P. L. Lutz & J. A.

Musick (Eds.), The Biology of Sea Turtles (pp. 315-341).

Quantum Resources Inc. (1995). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 1994. Prepared by Quantum Resources Inc. for Florida Power & Light Company, Juno Beach, FL.

Quantum Resources Inc. (1996). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 1995. Prepared by Quantum Resources Inc. for Florida Power & Light Company, Juno Beach, FL.

Quantum Resources Inc. (1997). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 1996. Prepared by Quantum Resources Inc. for Florida Power & Light Company, Juno Beach, FL.

Quantum Resources Inc. (1998). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 1997. Prepared by Quantum Resources Inc. for Florida Power & Light Company, Juno Beach, FL.

Quantum Resources Inc. (1999). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 1998. Prepared by Quantum Resources Inc. for Florida Power & Light Company, Juno Beach, FL.

Quantum Resources Inc. (2000). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 1999. Prepared by Quantum Resources Inc. for Florida Power & Light Company, Juno Beach, FL.

Quantum Resources Inc. (2001 ). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 2000. Prepared by Quantum Resources Inc. for Florida Power & Light Company, Juno Beach, FL.

Quantum Resources Inc. (2002). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 2001. Prepared by Quantum Resources Inc. for Florida Power & Light Company, Juno Beach, FL.

Quantum Resources Inc. (2003). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 2002. Prepared by Quantum Resources Inc. for Florida Power & Light Company, Juno Beach, FL.

Quantum Resources Inc. (2004). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 2003. Prepared by Quantum Resources Inc. for Florida Power & Light Company, Juno Beach, FL.

Quantum Resources Inc. (2005). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Reporl 2004. Prepared by Quantum Resources Inc. for Florida Power & Light Company, Juno Beach, FL.

32

Quantum Resources Inc. (2006). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Report 2005. Prepared by Quantum Resources Inc. for Florida Power & Light Company, Juno Beach, FL.

Quantum Resources Inc. (2007). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Report 2006. Prepared by Quantum Resources Inc. for Florida Power & Light Company, Juno Beach, FL.

Quantum Resources Inc. (2008). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Report 2007. Prepared by Quantum Resources Inc. for Florida Power & Light Company, Juno Beach, FL.

Quantum Resources Inc. (2009). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Report 2008. Prepared by Quantum Resources Inc. for Florida Power & Light Company, Juno Beach, FL.

Schroeder, B.A. & Thompson, N.B. (1987). Distribution of the loggerhead turtle (Caretta caretta) and leatherback turtle (Dermochelys coriacea) in the Cape Canaveral, Florida area; results from aerial surveys (NOAA Technical Report, NMFS-53).

Stewart, K., Johnson, C., & Godfrey, M. H. (2007). The minimum size of leatherbacks at reproductive maturity, with a review of sizes for nesting females from the Indian, Atlantic and Pacific Ocean basins. The Herpetological Journal, 17(2), 123-128.

Stewart, K., Sims, M., Meylan, A., Witherington, B., Brost, B., & Crowder, L. (2011).

Leatherback nests increasing significantly in Florida, USA; trends assessed over 30 years using multilevel modeling. Ecological Applications, 21(1), 263-273.

Witherington, B.E., & Ehrhart, L. M. (1989). Status and reproductive characteristics of green turtles (Chelonia mydas) nesting in Florida. In Ogren, L., F. Berry, K.

Bjorndal, H. Kumpf, R. Mast, G. Medina, H. Reichart and R. Witham (Eds.),

Proceeding of the Second Western Atlantic Turtle Symposium, Mayaguez, Puerto Rico, 12-16 October 1987 (pp-351-352). NOAA Technical Memorandum NMFS-SEFC-226.

Witherington, B., Bresette, & Herren, R. (2006). Chelonia mydas - green turtle. In Meylan, P.A. (Eds.), Biology and Conservation of Florida Turtles (pp90-104).

Chelonian Research Monographs.

33

7.0 Figures & Tables FLORIDA GULF OF MEXICO

+

-N-I Figure 1. Location of St. Lucie Plant on South Hutchinson Island, Florida.

34 I

INDIAN RIVER HUTCHINSON ISLAND INDIAN RIVER ATLANTIC OCEAN Figure 2. St. Lucie Plant cooling water intake and discharge system.

35

DRAWING NOT TO SCALE FPL

./u~~-- ST. LUCIE PLANT

~

-N-I Figure 3. Designation and location of nine 1.25 km segments (in brackets) and 36 one km segments surveyed for sea turtle nesting on South Hutchinson Island (1971-2023).

36

V)

V)

QJ z 16,000 14,000 12,000 10,000 8,000 6,000 4,000 T

• 2,000

~

en

~

+

+

U)

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co en en

~

~

U)

~

U)

~

U)

~

U)

~

00 en en 0

0

~

~

N en en en 0

0 0

0 0

~

~

~

N N

N N

N Year Figure 4. Number of loggerhead turtle nests on South Hutchinson Island from 1971 through 2023. Values for 1971 through 1979 are estimates (Section 2.1.1 ); values for 1981 through 2023 are from whole island surveys.

37

(/)

t; QJ z 2,500 2,000 1,500 1,000 500 0..........,:

~.~.~.TT T

T T

.~ T T

O'\\

U)

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O'\\

O'\\

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0 N

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N 0

N U) 0 N

N 0

N Figure 5. Number of green turtle nests on South Hutchinson Island from 1971 through 2023. Values for 1971 through 1979 are estimates (Section 2.1.1 ); values for 1981 through 2023 are from whole island surveys.

38

V)

~

600 500 400

~ 300 z

200 100 O****TTT T TT en U) en co en U) co en en en U) en en Year C

C N

U)

C C

N C

N U)

C N

N C

N Figure 6. Number of leatherback turtle nests on South Hutchinson Island from 1971 through 2023. Values for 1971 through 1979 are estimates (Section 2.1.1 ); values for 1981 through 2023 are from whole island surveys.

39

VI VI QJ u

u 100%

75%

~ 50%

+,I VI QJ z 25%

0%

• Loggerhead D Green A

B C

D E

F G

H J

K L

M N

0 p

Q R

s Figure 7. Loggerhead and green turtle nesting success (percentage of emergences resulting in nests) for each of the 1 km Zones A through S (North to South) on South Hutchinson Island for the 2023 nesting season.

40

900

• Loggerhead D Leatherback D Green 800 700 600 500 V, t:

a, z 400 300 200 100 0

A B

C D

E F

G H

J K

L M

N 0

p Q

R s

Zone t

Plant Figure 8. Number of turtle nests by species for each of the 1 km Zones A through S (North to South) on South Hutchinson Island for the 2023 nesting season (N=6,657 nests).

41

35%

30%

25%

C 0

.+i 20%

ra

"'C QJ

i..

c..

1n 15%

QJ z 10%

5%

0%

A B

C D

E F

G H

J Zones K

L M

N 0

t

• % Raccoons Only D % Crabs Only D % Raccoons and Crabs Ill% Other p

Q R

Plant s

Figure 9. Percentage of sea turtle nests depreciated by 1 km Zones A through S (North to South) on South Hutchinson Island for the 2023 nesting season.

42

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I Figure 11. Number of Kemp's ridley, olive ridley, hawksbill, and leatherback turtles captured and removed each year from the intake canal at the St. Lucie Plant, 1976 through 2023.

44 I

I

90 80 70 60

~ 50 I..

s

~

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Figure 12. Size distribution (Straight Standard Carapace Length; SSCL) of loggerhead turtles (N=355) captured and removed from the intake canal at the St. Lucie Plant during 2023.

45

U')

QJ 120 100 -+-----

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Figure 13. Size distribution (Straight Standard Carapace Length; SSCL) of green turtles (N=557) captured and removed from the intake canal at the St. Lucie Plant during 2023.

46

Year 1976-1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 19941 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 20141 2015 2016 2017 2018 2019 2020 2021 2022 2023 Total Mean*

Loggerhead 962 157 195 175 134 111 112 107 123 147 164 254 349 188 393 302 344 270 341 538 623 484 419 227 420 260 295 302 232 303 275 274 316 250 238 234 176 162 145 355 11,356 241 Green 156 14 22 35 42 17 20 12 61 179 193 673 549 191 268 190 345 321 292 394 286 428 267 101 299 161 444 217 127 196 134 181 159 182 246 260 155 70 187 557 8,631 184 Leatherback 7

1 1

1 5

2 1

2 1

1 2

4 2

1 1

1 2

2 2

2 1

1 1

1 2

47 1

Hawksbill 2

1 1

2 2

1 2

2 5

1 2

1 2

6 3

6 2

2 2

1 4

2 3

2 1

2 3

1 4

2 1

1 2

74 2

Kemp's ridley 3

1 6

5 2

1 4

2 5

3 2

1 1

2 1

3 3

2 7

2 7

6 1

11 13 7

4 1

4 110 2

Olive ridley 1

1 2

0 Total 1,130 172 220 218 181 133 132 121 187 337 361 933 906 382 666 495 691 600 636 944 914 917 692 330 725 424 751 521 362 503 414 465 486 435 497 508 339 237 334 921 20,220 430 Table 1. Total number of captured turtles removed from the intake canal at the St. Lucie Plant from 1976 through 2023. The number of mortalities is highlighted in gray. Mean excludes partial year of 1976 when 26 loggerheads were captured.

47

Loggerhead Green Leatherback Months 2023 Total Percent of Annual 2023 Total Percent of Annual 2023 Total Percent of Annual Captures Captures Captures Mean Captures Captures Captures Mean Captures Captures Captures Mean January 4

1,004 8.9%

21.4 36 1,106 12.8%

23.5 0

5 10.6%

0.1 February 4

981 8.7%

20.9 28 866 10.0%

18.4 0

5 10.6%

0.1 March 3

1,113 9.8%

23.7 7

904 10.5%

19.2 0

13 27.7%

0.3 April 24 1,055 9.3%

22.4 41 582 6.7%

12.4 1

9 19.1%

0.2 May 98 1,152 10.2%

24.5 93 596 6.9%

12.7 1

6 12.8%

0.1 June 102 1,321 11.7%

28.1 77 521 6.0%

11.1 0

2 4.3%

0.0 July 48 1,475 13.0%

31.4 6

418 4.8%

8.9 0

0 0.0%

0.0 August 21 961 8.5%

20.4 26 445 5.2%

9.5 0

1 2.1%

0.0 September 18 667 5.9%

14.2 54 756 8.8%

16.1 0

2 4.3%

0.0 October 20 600 5.3%

12.8 37 856 9.9%

18.2 0

1 2.1%

0.0 November 7

437 3.9%

9.3 59 774 9.0%

16.5 0

2 4.3%

0.0 December 6

564 5.0%

12.0 93 807 9.4%

17.2 0

1 2.1%

0.0 Total 355 11,330 100%

241 557 8,631 100%

184 2

47 100%

1 Table 2. Total number of loggerhead, green and leatherback turtles removed each month from the intake canal at the St. Lucie Plant from 1977 through 2023. Monthly totals exclude the partial year 1976 when 26 loggerheads were captured.

48

Hawksbill Kemp's Ridley Olive Ridley 2023 Total Percent of Annual 2023 Total Percent of Annual 2023 Total Percent of Annual Months Captures Captures Captures Mean Captures Captures Captures Mean Captures Captures Captures Mean January 0

1 1.4%

0.0 0

23 20.9%

0.5 1

1 50.0%

0.0 February 0

2 2.7%

0.0 1

33 30.0%

0.7 0

0 0.0%

0.0 March 0

9 12.2%

0.2 1

18 16.4%

0.4 0

0 0.0%

0.0 April 0

3 4.1%

0.1 0

17 15.5%

0.4 0

0 0.0%

0.0 May 1

4 5.4%

0.1 1

3 2.7%

0.1 0

1 50.0%

0.0 June 0

2 2.7%

0.0 1

3 2.7%

0.1 0

0 0.0%

0.0 July 0

14 18.9%

0.3 0

3 2.7%

0.1 0

0 0.0%

0.0 August 0

10 13.5%

0.2 0

0 0.0%

0.0 0

0 0.0%

0.0 September 0

14 18.9%

0.3 0

0 0.0%

0.0 0

0 0.0%

0.0 October 0

6 8.1%

0.1 0

2 1.8%

0.0 0

0 0.0%

0.0 November 1

7 9.5%

0.1 0

2 1.8%

0.0 0

0 0.0%

0.0 December 0

2 2.7%

0.0 0

6 5.5%

0.1 0

0 0.0%

0.0 Total 2

74 100%

2 4

110 100%

2 1

2 100%

0 Table 3. Total number of hawksbill, Kemp's ridley, and olive ridley turtles removed each month from the intake canal at the St. Lucie Plant from 1977 through 2023. Monthly totals exclude the partial year 1976 when 26 loggerheads were captured.

49

Species Captures Causal Injuries Causal Mortalities Hawksbill Turtle 6 hawksbills every 3 Not Authorized Not Authorized (Eretmochelys years imbricata)

Kemp's Ridley Turtle 24 Kemp's ridleys Not Authorized 1 Kemp's ridley every (Lepidochelys every 3 years 3 years kempil)

Leatherback Turtle 3 leatherbacks every Not Authorized Not Authorized (Dermoche/ys 3 years coriacea)

NA DPS of the Green Up to 741 NA DPS Up to 3 NA DPS Up to 18 NA DPS Turtle (Chelonia greens every 3 years greens every 3 years greens every 3 years mydas)

SA DPS of the Green Up to 39 SA DPS Up to 1 SA DPS Up to 1 SA DPS Turtle greens every 3 years green every 3 years green every 3 years (Chelonia mydas)

NWA DPS of the 729 loggerheads 1 loggerhead every 3 3 loggerheads every Loggerhead Turtle every 3 years years 3 years

( Caretta caretta)

U.S. DPS of the 3 sawfish every 3 Not Authorized Not Authorized Smalltooth Sawfish years (Pristis pectinata)

Table 4. Incidental take limits for continued operation of the St. Lucie plant. The 3-year time periods (with the exception of 2040-2043) are as follows: 2022-2024, 2025-2027, 2028-2030, 2031-2033, 2034-2036, 2037-2039, and 2040-2043.

50 I

I I I

8.0 Annual Environmental Operating Report 8.1 Introduction The St. Lucie Units 1 and 2 Environmental Protection Plans (EPP) require 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.

8.2 Sea Turtle Monitoring & Associated Activities Surveillance and maintenance of the light screen to minimize sea turtle disorientation as required by Section 4.2.3 of the EPP is ongoing. The vegetation light screen located on the beach dune between the plant and the ocean is routinely surveyed to determine its overall vitality. Evidence of sea turtle disorientation that occurs would also indicate any significant problems. Trees, vegetation or shade cloth are replaced as necessary to maintain the overall integrity of the light screen. Plant parking lot lighting is also designed and maintained to minimize light levels on the beach.

8.3 Taprogge Condenser Tube Cleaning System Operation A Taprogge condenser tube cleaning system (CTCS) became operational on St. Lucie Unit 2 in January 1996 and on Unit 1 in July 1996. This system utilizes sponge balls, approximately 23 mm in diameter, to clean the condenser tubes through which seawater flows to cool steam after its pass through the plant's turbines. This system improves plant performance while reducing the need for chemical treatments such as biocides or chlorine to control biofouling.

Normally, the St. Lucie CTCS utilizes about 1800 sponge balls, which are continually re-circulated through each of four "water boxes" on each unit. These sponge balls are retained in the system by a ball strainer located on the outlet of each water box. The ball strainers (mesh size 5 mm) are opened routinely to discharge debris, which can decrease flow and obstruct sponge ball movement through the system. The sponge balls are collected prior to opening, or back flushing, the ball strainers. At that time, the sponge balls are examined and replaced if they are worn to the point that they can no longer effectively clean the condenser tubes.

Sponge ball inventories and estimates of sponge ball loss to the environment have been performed since system start-up on both units. Number of ball strainer back flushes has also been tracked. In addition, daily beach surveys have been performed on plant property (approximately 2.5 miles) to note any sponge balls that may occur as a result of loss from the plant. This survey area has been extended during the turtle nesting season to almost 12 miles.

51

Ball loss reporting is required in accordance with the St. Lucie site environmental permit, a component of the site license. Best management practices are used to minimize the discharge of CTCS balls to the Atlantic Ocean.

The sponge cleaning balls are made of natural latex which will biodegrade and break down after about two months in a high nutrient seawater environment. Biodegradation can occur while balls are in service and weaken the latex sponge, leading to premature ball fatigue failure from cycle fatigue induced by the CTCS ball circulation impeller.

Although blue stripe balls are more resistant to biodegradation compared to orange balls, they are not as effective for tube cleaning during the last two weeks of service. The five-week maximum service interval is adequate to prevent most ball failure events.

Best management practices continue to be applied to minimize CTCS ball loss. The results of the program for 2023 are presented in Table 1.

8.4 Nonroutine Reports On December 6, 2023, a juvenile green sea turtle (Chelonia mydas) was recovered from the Plant's Intake Canal. Notification of the mortality to the NRC occurred via FPL letter L-2023-179 8.5 Routine Reports On April 12, 2023, St. Lucie Plant submitted to the NRC a copy of the 2022 Annual Environmental Operating Report. Notification to the NRC occurred via FPL letter L-2023-055.

52

8.6 Figures & Tables Table 1. PSL CTCS Ball Loss 2023 Summary 1A1 1A2 181 182 PSL 1 ALL

1. 8/

LOST

1. 8/

LOST

1. 8/W LOST

1. 8/W LOST

1. 8/W LOST COMMENTS w

w Jan-23 1

11 3

40 2

45 1

0 7

106 Feb-23 2

25 2

49 2

10 1

175 7

259 Mar-23 0

0 2

39 2

15 2

6 6

60 Apr-23 0

0 0

0 0

0 4

39 4

39 May-23 0

0 0

0 0

0 0

0 0

0 Jun-23 2

10 2

13 0

0 1

30 5

53 Jul-23 2

28 2

54 2

98 1

0 7

180 Aug-23 2

27 1

2 3

25 3

33 9

87 Sep-23 1

0 1

0 2

13 1

0 5

13 Oct-23 0

0 0

0 3

43 0

0 3

43 Nov-23 2

0 2

29 2

82 0

0 6

111 Dec-23 0

0 1

17 0

0 1

0 2

17 Summary 12 101 16 243 18 331 15 283 61 968 2A1 2A2 281 282 PSL 2 ALL

1. 8/

LOST

1. 8/

LOST

1. 8/W LOST

1. 8/W LOST

1. 8/W LOST COMMENTS w

w Jan-23 0

0 0

0 0

0 0

0 0

0 Feb-23 0

0 0

0 0

0 0

0 0

0 Mar-23 0

0 0

0 0

0 0

0 0

0 Apr-23 1

300 0

0 2

300 0

0 3

600 May-23 1

0 0

0 0

0 0

0 1

0 Jun-23 0

0 0

0 0

0 0

0 0

0 Jul-23 2

49 1

131 0

0 0

0 3

180 Aug-23 1

9 0

0 0

0 0

0 1

9 Sep-23 2

11 0

0 0

0 0

0 2

11 Oct-23 1

13 0

0 0

0 0

0 1

13 Nov-23 2

7 0

0 0

0 0

0 2

7 Dec-23 0

0 1

105 1

100 0

0 2

205 10 389 2

236 3

400 0

0 15 1025 Summary 53