View source for L-2021-082, Submittal of 2020 Annual Environmental Operating Report

{{Adams
| number = ML21105A014
| issue date = 04/15/2021
| title = Submittal of 2020 Annual Environmental Operating Report
| author name = Godes W
| author affiliation = Florida Power &amp; Light Co
| addressee name = 
| addressee affiliation = NRC/Document Control Desk, NRC/NRR
| docket = 05000335, 05000389
| license number = 
| contact person = 
| case reference number = L-2021-082
| document type = Annual Operating Report, Environmental Monitoring Report, Letter type:L
| page count = 51
}}

=Text=
{{#Wiki_filter:April 15, 2021 L-2021-082 10 CFR 50.4 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 2020 Annual Environmental Operating Report In accordance with Section 5.4.1.2 of the St. Lucie Units 1 and 2 Environmental Protection Plans (EPP), attached is the Annual Environmental Operating Report for calendar year 2020.
Sincerely, Wyatt Godes Licensing Manager St. Lucie Plant WG/rcs

==Attachment:==
Florida Power & Light Company - St. Lucie Plant - Annual Environmental Operating Report 2020 (50 pages) 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 2020 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 ............................................................................................ 10 2.2    Results for 2020 .................................................................................................... 11 2.2.1     Loggerhead Nesting....................................................................................... 11 2.2.2     Green Nesting ................................................................................................ 12 2.2.3     Leatherback Nesting ...................................................................................... 13 2.2.4     Predation ........................................................................................................ 13 2.2.5     Poaching......................................................................................................... 14 3.0   Intake Canal Monitoring ........................................................................................... 14 3.1    Barrier Nets ........................................................................................................... 14 3.1.1     Background .................................................................................................... 15 3.1.2     Current Methods & Results ........................................................................... 16 3.2    Intake Pipe Cleaning & Maintenance................................................................... 16 3.3    Power Plant Outages ............................................................................................ 17 4.0   Intake Canal Captures.............................................................................................. 17 4.1    Methodology .......................................................................................................... 17 4.1.1     Turtle Capture ................................................................................................ 17 4.1.2     Data Collection ............................................................................................... 18 4.2    Results for 2020 .................................................................................................... 19 4.2.1     Loggerhead Captures .................................................................................... 19 4.2.2     Green Captures.............................................................................................. 20 4.2.3     Leatherback, Hawksbill, Kemps, & Olive Ridley Captures ......................... 20 4.2.4     Recaptures ..................................................................................................... 20

4.2.5    Relative Condition .......................................................................................... 21 4.2.6    Mortalities & Injuries....................................................................................... 22 4.2.7    Smalltooth Sawfish Captures ........................................................................ 23 5.0   Sea Turtle Protective Activities ................................................................................ 23 5.1   NMFS Section 7 Consultations ............................................................................ 23 5.2   Sea Turtle Stranding & Salvage Network and Turtle Walks ............................... 25 5.2.1    Results for 2020 ............................................................................................. 25 5.3   Collaborative Efforts.............................................................................................. 25 6.0   References................................................................................................................ 27 7.0   Figures & Tables....................................................................................................... 32 8.0   Annual Environmental Operating Report ................................................................ 48 8.1   Introduction ............................................................................................................ 48 8.2   Sea Turtle Monitoring & Associated Activities ..................................................... 48 8.3   Taprogge Condenser Tube Cleaning System Operation ................................... 48 8.4   Nonroutine Reports ............................................................................................... 49 8.5   Routine Reports .................................................................................................... 49 8.6   Figures & Tables ................................................................................................... 50

Acronyms ABI      Applied Biology, Inc.
BO       Biological Opinion DEP      Department of Environmental Protection EAI      Ecological Associates, Inc.
ESA      Endangered Species Act EPP      Environmental Protection Plan FWC      Florida Fish and Wildlife Conservation Commission FWRI     Florida Fish and Wildlife Research Institute FPL      Florida Power & Light GLNC     Gumbo Limbo Nature Center HBOI     Harbor Branch Oceanographic Institute IRG      Inwater Research Group, Inc.
LMC      Loggerhead Marinelife Center NMFS     National Marine Fisheries Service NRC      Nuclear Regulatory Commission PIT      Passive Integrated Transponder SSCL     Straight Standard Carapace Length STSSN    Sea Turtle Stranding and Salvage Network USFW     U.S. Fish and Wildlife Service UESI     Underwater Engineering Services, Inc.
UIDS     Underwater Intrusion Detection System 4

Executive Summary Florida Power & Lights (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 plants 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 (Chelonia mydas), and leatherback (Dermochelys 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 FPLs 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 2020, 9,041 loggerhead, 626 green, and 450 leatherback nests were recorded on South Hutchinson Island.
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.
Since the plant became operational in 1976, turtles entrained in the intake canal have been systematically captured, measured, weighed, tagged, and released. During 2020, 339 sea turtles were removed from the intake canal, including 176 loggerheads, 155 greens, seven Kemps ridleys (Lepidochelys kempii), and one leatherback. The majority of these turtles (92.3%) were captured alive and released back into the ocean. Nineteen 5

(5.6%) were taken to rehabilitation facilities for treatment of injuries or disease and six turtles (1.8%) were 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 limit established by the 2016 Biological Opinion (BO) set forth by the National Marine Fisheries Service (NMFS). The Incidental Take Statement in the BO states that FPL would exceed its take limit if: 1) more than 623 loggerheads, 500 green turtles, 7 hawksbills, 8 Kemps ridleys, or 5 leatherbacks are captured annually; 2) more than 7 green turtles or 3 loggerheads are documented with severe causal injuries annually; 3) more than 5 green turtles or 3 loggerheads are documented as causal mortalities annually; 4) more than one hawksbill (Eretmochelys imbricata), Kemps ridley, or leatherback is documented with either a severe causal injury or as a causal mortality every two years; 5) more than one smalltooth sawfish (Pristis pectinata) is captured every five years or any smalltooth sawfish are ever killed.
During 2020, there were 176 loggerheads, 155 green turtles, seven Kemps ridleys, and one leatherback captured. There was one causal green injury and one causal green mortality. No loggerhead, Kemps ridley, or leatherback turtles were injured or killed due to plant operation. Also, no smalltooth sawfish were encountered at the St. Lucie Power Plant in 2020. Therefore, FPL did not exceed its take limit during 2020 under the latest BO issued by NMFS.
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 2020, Inwater Research Group (IRG) biologists responded to ten stranding events. Sea turtle nesting walks are conducted by FPL as public service programs during the summer sea turtle nesting season. Unfortunately, all sea turtle walks in 2020 were cancelled due to the COVID-19 pandemic.
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 six projects in 2020.
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1.0     Background 1.1     Area Description Florida Power & Lights (FPL) St. Lucie Plant is located on a 457-hectare site on South Hutchinson Island on Floridas 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 Ft. 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 plants 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 7

studies 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 35 annual environmental operating reports covering the period from 1983 through 2019 (ABI 1984-1994; Quantum Resources, Inc. 1995-2009; Inwater Research Group, Inc. 2010-2020). This report describes the 2020 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 7.
2.0     Sea Turtle Nest Monitoring Sea turtle nesting typically occurs along Floridas Atlantic coast from March through September. Furthermore, South Hutchinson Island is an important rookery for loggerhead (Caretta caretta), green (Chelonia mydas), and leatherback (Dermochelys 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 FPLs 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 plants 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.
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 2020, 36 one-km-long segments comprising the islands coastline have been surveyed seven days a week during the nesting season (Figure 3). These 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 10

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 2020 In 2020, Zones E-S were surveyed by Inwater 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 in South Hutchinson Island. Eighteen leatherback sea turtle nests and three false crawls were recorded in Zones A-S prior to the beginning of formal 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 O) was similar to the surrounding zones (Figure 7).
2.2.1 Loggerhead Nesting Most loggerhead nesting occurs on warm temperate and subtropical beaches (Dodd, 1988). Approximately 42,000 to 74,000 loggerhead turtle nests are deposited annually on Florida beaches (Turtle Expert Working Group [TEWG], 2000), ranking this loggerhead turtle rookery the largest in the world (Casale & Tucker, 2017; Ceriani &
Meylan, 2017). 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 10,000 loggerhead nests have been deposited annually on South Hutchinson Island during the last 30 years.
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In 2020, 9,041 loggerhead nests were recorded on South Hutchison Island (Figure 4). In Zones A-S (the north end of the island) biologists observed 3,987 nests (Figure 8). The first recorded nest was on April 18 and the last loggerhead nest was recorded on September 5. There were 5,714 loggerhead false crawls observed in Zones A-S.
Six hundred forty-two of the 3,987 loggerhead nests were marked to assess nest productivity. Three hundred fifty-nine nests were successfully inventoried, 186 were completely predated, 78 washed out, 16 could not be located again, and three were scattered by other nesting turtles. The 359 inventoried nests contained a cumulative total of 37,014 eggs. Of these, 21,876 successfully hatched and emerged from the marked nests. This represents an emergence success rate of 59.1%. There were also 579 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 6). Annual variations in nest densities are also common at other rookeries, and probably result from non-annual reproductive behavior (Heppell, Snover,
& Crowder, 2003). No relationships between annual fluctuations in nesting activity and plant operation or intake/discharge construction have ever been found. Furthermore, loggerhead nesting on South Hutchinson Island mirrors trends in nesting statewide.
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 years. This biennial pattern is also seen at other locations throughout their nesting range (Witherington et al., 2006).
In 2020, 626 green turtle nests were recorded on South Hutchison Island (Figure 5).
Biologists observed a total of 302 green turtle nests in Zones A-S (Figure 8). The first recorded nest of the season was on May 21 and the last green turtle nest was noted on September 5. There were 670 green turtle false crawls observed in Zones A-S.
One hundred nineteen of the 302 green turtle nests were marked to assess nest productivity. Fifty-eight nests were successfully inventoried, 28 nests washed out, 21 were completely predated, two were scattered by other nesting turtles, and ten were missing their marking stakes and could not be inventoried. The 119 inventoried nests contained a cumulative total of 6,728 eggs. Of these, 3,582 successfully hatched and emerged from the marked nests. This represents an emergence success rate of 53.2%.
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In addition, there were 140 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 2020, 450 leatherback sea turtle nests were recorded on South Hutchison Island (Figure 6). Biologists observed a total of 135 leatherback nests in Zones A-S (Figure 8).
The first recorded nest was on March 13 and the last leatherback nest was recorded on July 19. There were 38 leatherback sea turtle false crawls observed in the surveyed areas A-S.
Fifty-four of the 135 leatherback turtle nests were marked to assess nest productivity.
Forty-four nests were successfully inventoried, nine could not be located again, and one was completely predated. The 44 nests that were inventoried contained a cumulative total of 3,394 eggs. Of these, 1,032 successfully hatched and emerged from the marked nests unaided. This represents an emergence success rate of 30.4%. There were also 48 live leatherback turtles found during nest excavations. These hatchlings were not considered to have successfully emerged from the nest.
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). Biologists will need to continue monitoring leatherback nesting in order 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 depredated by ghost crabs (Ocypode quadrata) since nesting surveys began, quantification of ghost crab predation did not begin until 1983. Occasionally, sea turtle nests are depredated by other animals such as bobcats (Lynx rufus), fire ants (Solenopsis invicta), and various species of birds. However, this 13

only accounts for a small portion of the total number of predation events on South Hutchinson Island.
IRG biologists recorded a total of 692 predation events for South Hutchinson Island in 2020 within beach Sections E-S (Figure 9). Sea turtle nests on South Hutchinson Island were depredated by raccoons, ghost crabs, birds, fire ants, domestic dogs (Canis lupus), and coyotes (Canis latrans). The most abundant predators were raccoons, which accounted for 403 individual predation events. Ghost crabs were the second most abundant predator accounting for 104 events. Another 169 predation events consisted of a combination of raccoon and ghost crab predation. Other predators accounted for only 16 total predation events.
Nest excavation provides an opportunity to more accurately account for predation activity. For example, fire ant and ghost crab predation are not always evident from a cursory inspection of the sea turtle nests surface. Predators impacted 43.4% of nests (200 out of 461) where hatch success could be evaluated. Two hundred eight additional marked nests were completely predated prior to inventory.
2.2.5 Poaching EAI documented two human disturbances in 2020 just south of the Fort Pierce Inlet (zones A-D). On May 17, someone pulled nest marking stakes and trampled the nest.
On June 18, a nest was dug into and covered back up. FWC law enforcement was contacted about both incidents.
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, the backup 8-inch A1A, and 10-inch Underwater Intrusion Detection System or UIDS nets (Figure 2). These barrier nets serve to constrain the movement of turtles in order 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 waters surface. Periodic inspections of the barrier nets, as well as cleaning debris when warranted, are conducted by Underwater Engineering Services, Inc. (UESI).
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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, then it 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 A1A 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 waters 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 A1A. 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 22.9 cm x 22.9 cm. Prior to completion of the UIDS in December 1986, turtles unconfined by the A1A 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 A1A 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 90s), 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 15

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 A1A 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 in order 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 A1A net was replaced immediately after the storm and the primary 5-inch net was replaced on 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 in order 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.
3.1.2 Current Methods & Results Presently, the primary 5-inch and secondary 8-inch barrier nets are inspected quarterly and the 10-inch UIDS net is inspected semiannually. One hole was found in the primary barrier net in 2020 and was promptly repaired. No turtles were encountered beyond the primary barrier net in 2020.
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 16

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 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 outage in 2020. Unit 2 was in an outage from February 17 until March 19.
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 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 17

were attached to the surface and unweighted lines were used along the bottom. Turtles entangled in the nets generally remained at the waters 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 hours 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 days 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 days 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 in an attempt 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.
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 of all turtles as outlined in the BO issued by NMFS in May 2001. 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.
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4.2     Results for 2020 Methods to remove sea turtles from the intake canal include the use of tangle nets, dip nets, as well as hand capture. 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 2020, a total of 339 sea turtles were removed from the intake canal, including 176 loggerheads, 155 green turtles, seven Kemps ridleys (Lepidochelys kempii), and one leatherback (Figures 10 & 11; Table 1). The majority of these turtles (92.6%) were captured alive and released back to the ocean. Nineteen (5.6%) were taken to rehabilitation facilities for treatment of injuries or disease and six (1.8%) turtles were dead (including one that died while in transit to rehab). Specifically, 13 loggerheads, two green turtles, and three Kemps ridleys were sent to rehabilitation facilities for non-causal injuries. Also, one green turtle incurred a causal injury which was successfully treated in rehab prior to its release. Additionally, there were five noncausal mortalities (one loggerhead and four greens) and one causal green turtle mortality.
In 2020, all 339 turtles were captured east of the primary barrier net - 211 by tangle nets, 67 by hand capture, 48 by dip net, and 13 off of the primary barrier net. Proactive captures accounted for 33.9% of the turtles removed from the intake canal.
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. During 2020, monthly captures of loggerheads ranged from two in March to 35 in May (Table 2), with a monthly mean of 15. Loggerhead capture rates have exhibited considerable year-to-year fluctuation, but have shown an overall increasing trend since the plant started operation (Figure 10; Table 1). The size frequency of loggerheads ranges from predominantly juvenile to sub-adult animals, with adult animals captured mainly during the nesting season of April through September (Figure 12).
Of the 176 loggerheads captured, 64 were juveniles (SSCL < 70 cm), 59 were transitional (SSCL 70-84.9 cm), and 53 were adults (SSCL > 85 cm; Hirth, 1980; Figure 12). The intermediate group likely includes both mature and immature individuals. Of the 53 turtles classified as adults, 43 were females and 10 were males. Four additional 19

loggerheads were recorded as males, even though their SSCL was less than 85 cm, because sex was apparent from the animals tail length (Owens 1997).
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 10; 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 2020, monthly green turtle captures ranged from zero in April to 28 in November (Table 2), with a monthly mean of 13. Of the 155 green turtles captured in 2020, there were 151 juveniles or sub-adults (SSCL < 85 cm) and four adults (Witherington and Ehrhart, 1989; Figure 13). All of the animals classified as adults were female.
4.2.3 Leatherback, Hawksbill, Kemps, & Olive Ridley Captures Captures of leatherback, hawksbill, and Kemps 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 Kemps ridleys are caught between December and April. Only one olive ridley (Lepidochelys olivacea) has ever been captured at the St. Lucie site and it was encountered in May 2019.
In 2020, there were seven Kemps ridleys and one leatherback captured in the intake canal of the St. Lucie Plant (Table 1). The Kemps ridleys included two juveniles and five subadults (SSCL ranged from 23.9 cm to 58.5 cm). The leatherback was a subadult with a SCL of 113.1 cm (Stewart et al., 2007).
4.2.4 Recaptures Since plant operation began in 1976, a total of 18,728 sea turtles (including recaptures) have been captured, including 10,694 loggerheads, 7,817 green, 101 Kemps ridley, 71 hawksbills, 44 leatherbacks, and one olive ridley (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, 3,372 recapture events (810 loggerheads, 2,561 green turtles, and one 20

Kemps ridley) have occurred. The recapture rate in 2020 was 11.4% for loggerheads and 30.3% for green turtles.
Occasionally, turtles are captured that have been tagged by other researchers; there were three such captures in 2020. One subadult loggerhead and two juvenile green turtles were captured this year baring tags placed by other researchers. The loggerhead was rehabilitated by the Brevard Zoo for a boat strike injury prior to its release in 2019.
One juvenile green turtle was originally tagged by Anne Meylan in Bermuda in 2018.
The second green turtle stranded in North Carolina and was rehabbed by the Baltimore Aquarium before its release at the Cape Canaveral National Seashore in Florida this year.
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 infestation, epibiont coverage, injuries, and any other abnormalities that might affect overall vitality. Relative condition ratings can be influenced by a number of 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 turtles 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 2020, of the 176 loggerheads captured, 89.8% (158) were alive and in good condition. Only 9.7% (17) of all loggerheads were in fair or poor condition and 0.6% (1) were recovered postmortem. Of the 155 green turtles removed from the intake canal, 95.5% (148) were in good condition, 1.3% (2) were in fair or poor condition and 3.2% (5) were dead.
According to the 2016 Biological Opinion, FPL is 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 21

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.
Of the 339 turtles removed from the intake canal during the year, 295 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 (96.5%). However, one turtle (0.3%)
had a severe fresh scrape and 3.5% of turtles had either moderate or severe fresh scrapes. Both of these 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 the 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 1.4% for the period 1985 to present (Table 1). Over the entire monitoring programs history (1976-2020), 187 (1.7%) loggerheads and 137 (1.8%) green turtles entrained in the canal were dead. Only four Kemps ridley mortalities have been documented at the St. Lucie Plant during 1987 and 1988. The only hawksbill mortality was recorded in 2014 and there have been no leatherback mortalities in the history of the project.
In 2020, six sea turtle mortalities were recorded at the St. Lucie plant intake canal. One of the mortalities was considered causal to plant operations (discussed below) and there was one causal injury.
There was one causal mortality in 2020. On February 8th, a large subadult green turtle was recovered from atop the permanent 5-inch barrier net. Lethargic and suffering from severe papillomatosis, this turtle died while in transit to rehab. The turtle was then taken to Dr. Nancy Mettee, DVM for necropsy and it was determined that, "acute respiratory 22

failure secondary to near drowning was the most likely cause of death." Even though this turtle was initially sent for rehab it was still classified as a causal mortality.
One turtle was taken to a rehabilitation facility for a causal injury in 2020. On September 5th, a juvenile green turtle was recovered with a severe fresh scrape. The anterior carapace was punctured, exposing the lungs. The injury was sustained in part due to embedded barnacles in this area of the carapace. IRG biologists transported this turtle to the Loggerhead Marinelife Center in Juno Beach for rehabilitation. The turtle made a full recovery and was released prior to the end of the year.
4.2.7 Smalltooth Sawfish Captures The Incidental Take Limit established by the 2016 Biological Opinion set forth by NMFS is one non-lethal capture (take) of U.S. Distinct Population Segment smalltooth sawfish (Pristis pectinata) every five years. No smalltooth sawfish were encountered in the St. Lucie Plant intake canal in 2020.
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 a number of 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%
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of the 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 reinitiating a Section 7 consultation was required. 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 is to the Incidental Take Statement. It now states that FPL would exceed its take limit if: 1) more than 623 loggerheads, 500 green turtle, seven hawksbills, eight Kemps 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, Kemps 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.
Since 2016, FPL has 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 is ongoing with NMFS. Also, in 2018, FPL exceeded its take with regard to causal green turtle mortalities. Then, in both 2018 and 2019, FPL exceeded its take limit because more Kemps ridleys were captured than allowable under the latest BO issued by NMFS (no more than eight can be encountered in any given year as stipulated in the Incidental Take Statement). FPL and the NRC have already reinitiated Section 7 consultations with NMFS.
During 2020 there were 176 loggerheads, 155 green turtles, 7 Kemps ridleys, and one leatherback captured. There was one causal injury and one causal mortality (both green turtles). Also, no hawksbill or Kemps ridley turtles were injured or killed. Furthermore, no smalltooth sawfish were encountered in the intake canal. Therefore, FPL did not exceed its take limit during 2020 under the latest BO issued by NMFS.
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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, IRGs 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 2020 During 2020, IRG biologists responded to ten (5 green and 5 loggerheads) stranding events in St. Lucie County. Two live turtles were transported to rehabilitation facilities.
The remaining eight turtles were found dead in various stages of decomposition. The probable cause of stranding included three shark attacks, one boat strike, one fisheries interaction, and one chronic debilitation syndrome. The remaining four turtles were either too decomposed, had injuries of an unknown origin, or otherwise lacked any salient wounds or abnormalities to indicate a probable cause of death.
Due to the coronavirus pandemic COVID-19, FPL did not conduct any turtle walks in 2020. After consultation with FWC, it was decided that turtle walks should be suspended until the risk of transmission had abated.
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 six research projects in 2020.
Unhatched eggs from loggerhead nests were collected for stable isotope analysis by the Florida Fish and Wildlife Research Institute. Blood from juvenile green turtles was provided to a Florida Atlantic University (FAU) Masters student studying the role of 25

immunosuppression in papillomatosis. Another FAU Masters student work was titled, Ultrasonography of Shoulder Fat Thickness as a Non-Invasive Technique for Estimating Body Condition in Green & Loggerhead Sea Turtles." Yet another FAU student placed data loggers in loggerhead nests to evaluate the characteristics of highly successful sea turtle nests. FAU/HBOI researchers were also able to collect baseline health information on green turtles as part of an Indian River Lagoon health assessment. Lastly, a Ph.D. student from Arizona State University utilized 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.
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Quantum Resources Inc. (2001). Florida Power & Light Company, St. Lucie Unit 2 Annual Environmental Operating Report 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 Report 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 Report 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 Report 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 Report 2004. Prepared by Quantum Resources Inc. for Florida Power & Light Company, Juno Beach, FL.
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).
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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.
Turtle Expert Working Group. (2000). Assessment update for the Kemps ridley and loggerhead sea turtle populations in the western Atlantic (NOAA Technical Memorandum NMFS-SEFSC-444). U.S. Department of Commerce.
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.
Zug G.R., Chaloupka M., & Balazs G.H. (2006). Age and growth in olive ridley sea turtles (Lepidochelys olivacea) from the Northcentral Pacific: a skeletochronological analysis. Marine Ecology, 27(3), 263-70.
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7.0    Figures & Tables Figure 1. Location of St. Lucie Plant on South Hutchinson Island, Florida.
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Figure 2. St. Lucie Plant cooling water intake and discharge system.
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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 (1971-2020).
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Figure 4. Number of loggerhead turtle nests on South Hutchinson Island from 1971 through 2020. Values for 1971 through 1979 are estimates (Section 2.1.1); values for 1981 through 2020 are from whole island surveys.
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Figure 5. Number of green turtle nests on South Hutchinson Island from 1971 through 2020. Values for 1971 through 1979 are estimates (Section 2.1.1); values for 1981 through 2020 are from whole island surveys.
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Figure 6. Number of leatherback turtle nests on South Hutchinson Island from 1971 through 2020. Values for 1971 through 1979 are estimates (Section 2.1.1); values for 1981 through 2020 are from whole island surveys.
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Plant 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 2020 nesting season.
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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 2020 nesting season (N=4,759 nests).
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Plant Figure 9. Percentage of sea turtle nests depredated by 1 km Zones A through S (North to South) on South Hutchinson Island for the 2020 nesting season.
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Figure 10. Number of loggerhead and green turtles captured and removed each year from the intake canal at the St. Lucie Plant, 1976 through 2020.
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Figure 11. Number of Kemps ridley, olive ridley, hawksbill, and leatherback turtles captured and removed each year from the intake canal at the St. Lucie Plant, 1976 through 2020.
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Figure 12. Size distribution (Straight Standard Carapace Length; SSCL) of loggerhead turtles (N=176) captured and removed from the intake canal at the St. Lucie Plant during 2020.
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Figure 13. Size distribution (Straight Standard Carapace Length; SSCL) of green turtles (N=155) captured and removed from the intake canal at the St. Lucie Plant during 2020.
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Year    Loggerhead            Green         Leatherback         Hawksbill      Kemp's ridley      Olive ridley     Total 1976 - 1984     962    74           156    15         7                  2               3                               1,130  89 1985     157     4           14                                   1                                                 172   4 1986     195    27           22      1         1                  1               1                                 220  28 1987     175    11           35                                   2               6                                 218  13 1988     134     6           42      2                                            5       2                         181  10 1989     111     4           17      1         1                  2               2       2                         133   5 1990     112     1           20      2                                                                              132   3 1991     107     1           12                                   1               1                                 121   1 1992     123     2           61      2         1                  2                                                 187   4 1993     147                 179     1         5                  2               4                                 337   1 1994     164                 193     4         2                                  2                                 361   4 1995     254     1           673    15         1                                  5                                 933  16 1996     349     3           549     4                            5               3                                 906   7 1997     188                 191     5         2                  1                                                 382   5 1998     393     1           268               1                  2               2                                 666   1 1999     302     2           190     4         1                  1               1                                 495   6 2000     344     2           345     2                            2                                                 691   4 2001     270     1           321     5         2                  6               1                                 600   6 2002     341                 292     3                            3                                                 636   3 2003     538                 394     2         4                  6               2                                 944   2 2004     623     2           286     1         2                  2               1                                 914   3 2005     484     2           428     1                            2               3                                 917   3 2006     419    22           267     2         1                  2               3                                 692  24 2007     227     3           101     1         1                  1                                                 330   4 2008     420     2           299     4                            4               2                                 725   6 2009     260     1           161     1         1                  2                                                 424   2 2010     295     2           444     6         2                  3               7                                 751   8 2011     302     1           217     8                            2                                                 521   9 2012     232     1           127     2         2                  1                                                 362   3 2013     303     2           196     3         2                  2                                                 503   5 2014     275     1           134     2                            3     1         2                                 414   4 2015     274     1           181     8         2                  1               7                                 465   9 2016     316     1           159     8         1                  4               6                                 486   9 2017     250     3           182     5                            2               1                                 435   8 2018     238                 246     9         1                  1              11                                 497   9 2019     234     2           260     3                                           13                 1               508   5 2020     176     1           155     5         1                                  7                                 339   6 Total    10,694 187          7,817 137         44     0           71     1        101      4         1        0    18,728 329 Mean*        242     4           178     3         1     0            2     0         2       0         0        0      425   7 Table 1. Total number of captured turtles removed from the intake canal at the St. Lucie Plant from 1976 through 2020. Number of mortalities is highlighted in gray. Mean excludes partial year of 1976 when 26 loggerheads were captured.
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Loggerhead                                Green Percent                                Percent Months        2020        Total        of    Annual      2020     Total        of      Annual Captures Captures Captures        Mean     Captures Captures Captures       Mean January          9          981       9.2%      22.3       26      1,048     13.4%        23.8 February         13         960       9.0%      21.8       15       813      10.4%        18.5 March           2         1,071      10.0%     24.3       7        885      11.3%        20.1 April          10        1,017      9.5%      23.1       0        535       6.8%        12.2 May            35         998       9.4%      22.7       4        497       6.4%        11.3 June           28        1,182      11.1%     26.9       1        439       5.6%        10.0 July          18        1,393      13.1%     31.7       1        412       5.3%         9.4 August          11         913       8.6%      20.8       13       414       5.3%         9.4 September         14         645       6.0%      14.7       20       695       8.9%        15.8 October          16         560       5.2%      12.7       24       797      10.2%        18.1 November          9          413       3.9%       9.4       28       637       8.1%        14.5 December          11         535       5.0%      12.2       16       645       8.3%        14.7 Total         176       10,668     100.0%    242.5      155      7,817    100.0%       177.7 Table 2. Total number of loggerhead and green turtles removed each month from the intake canal at the St. Lucie Plant from 1977 through 2020. Monthly totals exclude the partial year 1976 when 26 loggerheads were captured.
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Leatherback                              Hawksbill                          Kemp's Ridley Percent                                Percent                                 Percent Months 2020     Total       of   Annual     2020       Total       of   Annual                 Total       of    Annual Captures Captures Captures   Mean    Captures Captures Captures    Mean   2020 Captures Captures Captures    Mean January       0         5       11.4%     0.1      0           1       1.4%     0.0        1           21      20.8%      0.5 February      0         5       11.4%     0.1      0           2       2.8%     0.0        4           31      30.7%      0.7 March        0        13       29.5%     0.3      0           8       11.3%    0.2        0           16      15.8%      0.4 April       0         7       15.9%     0.2      0           3       4.2%     0.1        0           17      16.8%      0.4 May         0         5       11.4%     0.1      0           3       4.2%     0.1        0           2       2.0%       0.0 June        0         2       4.5%      0.0      0           2       2.8%     0.0        0           2       2.0%       0.0 July       0         0       0.0%      0.0      0          14       19.7%    0.3        0           3       3.0%       0.1 August       0         1       2.3%      0.0      0          10       14.1%    0.2        0           0       0.0%       0.0 September       0         2       4.5%      0.0      0          14       19.7%    0.3        0           0       0.0%       0.0 October       0         1       2.3%      0.0      0           6       8.5%     0.1        1           2       2.0%       0.0 November       1         2       4.5%      0.0      0           6       8.5%     0.1        1           2       2.0%       0.0 December       0         1       2.3%      0.0      0           2       2.8%     0.0        0           5       5.0%       0.1 Total       1        44      100.0%     1.0      0          71      100.0%    1.6        7          101     100.0%      2.3 Table 3. Total number of leatherback, hawksbill, and Kemps ridley turtles removed each month from the intake canal at the St. Lucie Plant from 1977 through 2020. Monthly totals exclude the partial year 1976 when 26 loggerheads were captured.
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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 plants turbines. This system improves plant performance while reducing the need for chemical treatments such and 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 48

of loss from the plant. This survey area has been extended during the turtle nesting season to almost 12 miles.
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 2020 are presented in Table 1.
8.4     Nonroutine Reports On February 8, 2020 a lethargic subadult female green sea turtle (Chelonia mydas) was captured transported to a rehabilitation facility. The turtle died on the way to the rehabilitation facility. Notification to the NRC of the mortality occurred via FPL letter L-2020-028.
On September 11, 2020 and October 23, 2020, two live, healthy giant manta rays (Mobula birostris) were captured and released unharmed from the St Lucie Plant intake canal. Notification to the NRC of these unusual captures occurred via FPL letter L-2020-159.
8.5     Routine Reports On April 15, 2020 St. Lucie submitted to the NRC a copy of the 2019 Annual Environmental Operating Report. The report was submitted to the NRC via FPL letter L-2020-068.
On June 9, 2020 St. Lucie submitted to the NRC a copy of a Minor Permit Revision for our Wastewater Facility Permit (permit number FL0002208) for the use of Chlorine Dioxide. This was submitted to the NRC via FPL letter L-2020-095.
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8.6   Figures & Tables Table 1. PSL CTCS Ball Loss 2020 Summary 1A1        1A2         1B1            1B2         PSL 1 ALL
         #B/W LOST #B/W LOST    #B/W LOST      #B/W LOST   #B/W LOST      COMMENTS Jan-20    1     22   1     36    2      64      4     270    8       392 Feb-20    2     20   2     89    2      58      2      12    8       179 Mar-20    2     82   1     30    2      81      2      28    7       221 Apr-20    2     15   2     66    1       0      2      46    7       127 May-20     3     89   2     62    1      42      2      11    8       204 Jun-20    1     45   2    105    2      17      2       0    7       167 Jul-20   2     12   2     68    1      42      2      13    7       135 Aug-20    1     44   2     50    2      89      2     191    7       374 Sep-20    1      0   1     42    3     518      2       6    7       566 Oct-20    0      0   0      0    1      44      1      36    2        80 Nov-20    2      9   1     18    1      12      1       5    5        44 Dec-20    1     44   2     10    1       6      1       1    5        61 Summary   18    382  18    576   19     973     23     619   78      2550 2A1        2A2         2B1            2B2        PSL 2 ALL
         #B/W LOST #B/W LOST    #B/W LOST      #B/W LOST   #B/W LOST      COMMENTS Jan-20    2     24   2     49    3      71      1      3    8        147 Feb-20    2    110   0     0     1      72      1      0    4        182 Mar-20     1     0    1     0     1      0       0      0    3         0 Apr-20    1     10   1     45    0      0       1      7    3         62 May-20     3     84   2     12    2     145      2      53   9        294 Jun-20    1     7    1    426    1      0       1      0    4        433 Jul-20   2     22   2     84    1      0       2      35   7        141 Aug-20    2     27   2     16    2     172      2      31   8        246 Sep-20    2     0    2     92    1     100      3      37   8        229 Oct-20    2     36   2     66    1      49      1      3    6        154 Nov-20    2     25   2     59    1      0       1      8    6         92 Dec-20    1     14   1     49    1      0       2      0    5         63 Summary   21    359  18    898   15     609     17     177  71       2043 50}}