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Arendt MD, Schwenter JA, Owens DW. Climate-mediated population dynamics for the world's most endangered sea turtle species. Sci Rep 2023; 13:14444. [PMID: 37660203 PMCID: PMC10475092 DOI: 10.1038/s41598-023-41647-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 08/29/2023] [Indexed: 09/04/2023] Open
Abstract
Restricted range, and subsequently small population size, render Kemp's ridley sea turtles (Lepidochelys kempii) the most globally endangered sea turtle species. For at least two decades preceding conservation, high egg harvest rates reduced annual cohort recruitment. Despite > 50 years of dedicated conservation, annual nest counts remain well below a landmark 1947 level. Prior studies attribute less robust than anticipated nest count rebound to multiple contemporary concerns; however, analyses herein convey optimistic interpretation. In objective 1, improved analysis of the ratio of hatchlings to nests since 1966 suggested age structure stabilization as a more likely basis for nest count trends after 2005 than density-dependent effects. In objective 2, multiple regression revealed a lagged (≤ 13 years prior) climate influence on nests (adj. r2 = 0.82) and hatchlings per nest (adj. r2 = 0.94) during 2006-2022. In objectives 3 and 4, a simulator modeled population response to changes in a suite of demographic rates including survival. Across 32 models, high survival and dynamic cohort sex ratio, sexual maturity age, and the ratio of clutch frequency to remigration interval best explained nesting trends during 1966-2022. These novel findings provide alternative perspective for evaluating species recovery criteria and in turn refine future nest trend expectations.
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Affiliation(s)
- Michael D Arendt
- South Carolina Department of Natural Resources, Marine Resources Division, 217 Fort Johnson Road, Charleston, SC, 29412, USA.
| | - Jeffrey A Schwenter
- South Carolina Department of Natural Resources, Marine Resources Division, 217 Fort Johnson Road, Charleston, SC, 29412, USA
| | - David W Owens
- College of Charleston, Grice Marine Biology Laboratory (Retired), 205 Fort Johnson Road, Charleston, SC, 29412, USA
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Corniuk RN, Lynch JM, Arendt MD, Braun-McNeill J, Owens DW, Valverde RA, Kucklick JR, McClellan-Green PD. Using Plasma Vitellogenin in Loggerhead Sea Turtles to Assess Reproductive Maturation and Estrogen-Like Contaminant Exposure. Environ Toxicol Chem 2023; 42:1309-1325. [PMID: 36942377 DOI: 10.1002/etc.5612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 03/09/2023] [Accepted: 03/16/2023] [Indexed: 05/09/2023]
Abstract
Vitellogenin (VTG), an egg yolk precursor, is abnormally produced by male and juvenile oviparous species after exposure to estrogens. Plasma VTG in loggerhead sea turtles (Caretta caretta) helped us understand their reproductive maturation and investigate it as a biomarker of contaminant exposure. The presence of VTG was screened in plasma from 404 loggerheads from the northwestern Atlantic Ocean using a freshwater turtle antibody in western blots. The concentrations of VTG were semiquantified using band intensities calibrated to results from a loggerhead antibody enzyme-linked immunoassay. The detection and concentrations of VTG were in (from highest to lowest): nesting females, in-water adult females, subadult females, smaller females, unknown sex, and males. Loggerheads from this region begin vitellogenesis at ≅77 cm straight carapace length. We classified VTG expression as abnormal in nine male or juvenile turtles. Organochlorine contaminant (OC) concentrations were measured in blood and/or fat biopsies of some turtles. One abnormal VTG female had the second highest fat polychlorinated biphenyl (PCB) and 4,4'-dichlorodiphenyldichloroethylene concentrations compared among 43 VTG-negative juveniles. The nine VTG-abnormal turtles had average blood PCB concentrations 8.5% higher, but not significantly different, than 46 VTG-negative juveniles (p = 0.453). In turtles less than 77 cm, blood PCB concentrations were significantly, but weakly, correlated with semiquantified VTG concentrations (tau = 0.1, p = 0.004). Greater blood OC concentrations were found in adult females than in males, which motivated the creation of a conceptual model of OC, VTG, and hormone concentrations across a reproductive cycle. A decision tree is also provided incorporating VTG as a sexing tool. Abnormal VTG expression cannot conclusively be linked to endocrine disruption caused by these OC concentrations. Studies should further investigate causes of abnormal VTG expression in wild sea turtles. Environ Toxicol Chem 2023;00:1-18. © 2023 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.
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Affiliation(s)
| | - Jennifer M Lynch
- National Institute of Standards and Technology, Waimanalo, Hawaii, USA
- Duke University Marine Laboratory, Beaufort, North Carolina, USA
| | - Michael D Arendt
- Marine Resources Division, South Carolina Department of Natural Resources, Charleston, South Carolina, USA
| | | | - David W Owens
- College of Charleston, Charleston, South Carolina, USA
| | - Roldán A Valverde
- Southeastern Louisiana University, Hammond, Louisiana, USA
- Sea Turtle Conservancy, Gainesville, Florida, USA
| | - John R Kucklick
- National Institute of Standards and Technology, Charleston, South Carolina, USA
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Arendt MD, Webster RP, Schwenter JA. CORRIGENDUM: High annual survival suggested by size structure of Kemp’s ridley sea turtles captured by coastal research trawling in the Northwest Atlantic Ocean since 1990. ENDANGER SPECIES RES 2022. [DOI: 10.3354/esr01190_c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- MD Arendt
- Marine Resources Division, South Carolina Department of Natural Resources, 217 Fort Johnson Road, Charleston, South Carolina 29412, USA
| | - RP Webster
- Marine Resources Division, South Carolina Department of Natural Resources, 217 Fort Johnson Road, Charleston, South Carolina 29412, USA
| | - JA Schwenter
- Marine Resources Division, South Carolina Department of Natural Resources, 217 Fort Johnson Road, Charleston, South Carolina 29412, USA
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Arendt MD, Webster RP, Schwenter JA. High annual survival suggested by size structure of Kemp’s ridley sea turtles captured by coastal research trawling in the Northwest Atlantic Ocean since 1990. ENDANGER SPECIES RES 2022. [DOI: 10.3354/esr01190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Arendt MD, Schwenter JA, Owens DW, Valverde RA. Theoretical modeling and neritic monitoring of loggerhead Caretta caretta [Linnaeus, 1758] sea turtle sex ratio in the southeast United States do not substantiate fears of a male-limited population. Glob Chang Biol 2021; 27:4849-4859. [PMID: 34273224 PMCID: PMC9291020 DOI: 10.1111/gcb.15808] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 06/30/2021] [Accepted: 07/01/2021] [Indexed: 06/13/2023]
Abstract
Sea turtles are among several hundred species whose sex is determined by incubation conditions during critical developmental periods. Consequently, these marine reptiles may be vulnerable to global climate change, and under the assumption of continued climate warming, numerous studies pose dire predictions for future populations based primarily on hatchling sex ratio data. Alternatively, as long-lived species that take decades to reach maturity, without inherent coping mechanisms for such change, sea turtles could not have persisted across geological epochs. Globally, loggerhead Caretta caretta [Linnaeus, 1758] sea turtles occupy temperate zones, with ontogenetic development that spans the entirety of gyres associated with respective ocean basins. The largest rookery for this species occurs in the Northwest Atlantic Ocean (NWA) population, where a 30-year cycle in annual nest counts is reported through 2018. Complementary studies document a lagged association between these annual nest counts and the Atlantic Multidecadal Oscillation (AMO); however, the underlying mechanism for this association remains elusive. Therefore, objective 1 evaluated the effect of AMO-mediated cohort resonance on the demographic structure of a theoretical neritic assemblage under variable cohort abundance and female proportion but stable annual survival during 165-year runs (i.e., extent of AMO data). For objective 2, blood samples were used to assign sex to 2217 loggerhead sea turtles captured by research trawling (2000 to 2019) on the inner continental shelf from St. Augustine, FL (29.9°N) to Winyah Bay, SC (33.1°N). Shorter oceanic duration of less female-biased cohorts from the AMO cold phase synchronized peak adult male and adult female co-occurrence during subsequent warm phases three decades later. Grand sex ratio predicted from testosterone was 67% female (n = 1484), with a slight temporal female decline. Our findings suggest greater population sex ratio plasticity than predicted solely from terrestrial nesting data.
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Affiliation(s)
- Michael D. Arendt
- Marine Resources DivisionSouth Carolina Department of Natural ResourcesCharlestonSCUSA
| | - Jeffrey A. Schwenter
- Marine Resources DivisionSouth Carolina Department of Natural ResourcesCharlestonSCUSA
| | - David W. Owens
- Grice Marine LaboratoryCollege of CharlestonCharlestonSCUSA
| | - Roldán A. Valverde
- Department of Biological SciencesSoutheastern Louisiana UniversityHammondLAUSA
- Sea Turtle ConservancyGainesvilleFLUSA
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Molter CM, Norton TM, Hoopes LA, Nelson SE, Kaylor M, Hupp A, Thomas R, Kemler E, Kass PH, Arendt MD, Koutsos EA, Page-Karjian A. Health and nutrition of loggerhead sea turtles (Caretta caretta) in the southeastern United States. J Anim Physiol Anim Nutr (Berl) 2021; 106:205-219. [PMID: 34120377 DOI: 10.1111/jpn.13575] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 04/13/2021] [Accepted: 04/26/2021] [Indexed: 11/28/2022]
Abstract
Loggerhead sea turtles (Caretta caretta) are opportunistic carnivores that feed primarily on benthic invertebrates and fish. Sea turtle rehabilitation requires provision of a species-specific, balanced diet that supplies nutrition similar to that of a wild diet; this can be challenging because free-ranging loggerheads' diets vary depending on their life stage and geographic location, with predominant prey species dictated by local availability. The goal of this study was to better understand the nutritional needs of subadult and adult loggerheads in rehabilitation. This was accomplished by conducting a retrospective survey of stomach contents identified during gross necropsy of 153 deceased loggerheads that stranded in coastal Georgia, USA. A total of 288 different forage items were identified; the most frequently observed prey items belong to the subphylum Crustacea (N = 131), followed by bony fish (Osteichthyes; N = 45), gastropod mollusks (N = 40), bivalve mollusks (N = 23), and Atlantic horseshoe crabs (Limulus polyphemus; N = 15). The proportions of certain prey items differed significantly with turtle size; adult turtles ate proportionately more gastropods (p = 0.001), and subadults ate proportionately more fish (p = 0.01). Stomach contents information was used to determine common local prey items (blue crab, cannonball jellyfish, horseshoe crab, whelk), which were evaluated for nutritional content. Additionally, we compared hematology and plasma biochemistry profiles (including proteins, trace minerals, and vitamins) between four cohorts of loggerhead turtles, including free-ranging subadults and adults, nesting females, and loggerheads undergoing rehabilitation. This information was applied to inform a regionally specific, formulated diet for tube feeding, and a supplement containing vitamins and minerals for captive loggerheads, to more closely approximate the nutritional content of their natural diet. Assessing the regional and temporal variability in loggerhead diets is an important component in their effective conservation because resultant data can be used to help understand the impacts of environmental perturbations on benthic food webs.
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Affiliation(s)
- Christine M Molter
- School of Veterinary Medicine, University of California Davis, Davis, California, USA
| | - Terry M Norton
- Georgia Sea Turtle Center/Jekyll Island Authority, Jekyll Island, Georgia, USA
| | | | - Steven E Nelson
- Georgia Sea Turtle Center/Jekyll Island Authority, Jekyll Island, Georgia, USA.,College of Veterinary Medicine, University of California, Davis, Davis, California, USA
| | - Michelle Kaylor
- Georgia Sea Turtle Center/Jekyll Island Authority, Jekyll Island, Georgia, USA
| | - Amy Hupp
- Georgia Sea Turtle Center/Jekyll Island Authority, Jekyll Island, Georgia, USA
| | - Rachel Thomas
- Georgia Sea Turtle Center/Jekyll Island Authority, Jekyll Island, Georgia, USA
| | - Erika Kemler
- Georgia Sea Turtle Center/Jekyll Island Authority, Jekyll Island, Georgia, USA
| | - Philip H Kass
- College of Veterinary Medicine, University of California, Davis, Davis, California, USA
| | - Michael D Arendt
- Marine Resources Division, South Carolina Department of Natural Resources, Marine Resources Research Institute, Charleston, South Carolina, USA
| | | | - Annie Page-Karjian
- Harbor Branch Oceanographic Institute, Florida Atlantic University, Fort Pierce, Florida, USA
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Perrault JR, Arendt MD, Schwenter JA, Byrd JL, Tuxbury KA, Stacy NI. Comparison of 2 glucose analytical methodologies in immature Kemp's ridley sea turtles: dry chemistry of plasma versus point-of-care glucometer analysis of whole blood. J Vet Diagn Invest 2021; 33:595-599. [PMID: 33739180 DOI: 10.1177/10406387211001830] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Blood glucose measurements provide important diagnostic information regarding stress, disease, and nutritional status. Glucose analytical methodologies include dry chemistry analysis (DCA) of plasma and point-of-care (POC) glucometer analysis of whole blood; however, these 2 methods differ in cost, required sample volume, and processing time. Because POC glucometers use built-in equations based on features of mammalian blood to convert whole blood measurements to plasma equivalent units, obtained glucose data must be compared and validated using gold-standard chemistry analytical methodology in reptiles. For in-water, trawl-captured, immature Kemp's ridley sea turtles (Lepidochelys kempii) from Georgia, USA, we observed significant, positive agreement between the 2 glucose determination methods; however, the glucometer overestimated glucose concentrations by 1.4 mmol/L on average in comparison to DCA and produced a wider range of results. The discordance of these results suggests that POC glucometer glucose data should be interpreted in the context of methodology- and brand-specific reference intervals along with concurrent packed cell volume data.
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Affiliation(s)
| | - Michael D Arendt
- Marine Resources Division, South Carolina Department of Natural Resources, Charleston, SC
| | - Jeffrey A Schwenter
- Marine Resources Division, South Carolina Department of Natural Resources, Charleston, SC
| | - Julia L Byrd
- South Atlantic Fishery Management Council, North Charleston, SC
| | - Kathryn A Tuxbury
- Animal Health Department, New England Aquarium, Central Wharf, Boston, MA
| | - Nicole I Stacy
- Aquatic, Amphibian, and Reptile Pathology Program, Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL
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Perrault JR, Arendt MD, Schwenter JA, Byrd JL, Harms CA, Cray C, Tuxbury KA, Wood LD, Stacy NI. Blood analytes of immature Kemp's ridley sea turtles ( Lepidochelys kempii) from Georgia, USA: reference intervals and body size correlations. Conserv Physiol 2020; 8:coaa091. [PMID: 33304585 PMCID: PMC7720087 DOI: 10.1093/conphys/coaa091] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/14/2020] [Accepted: 10/26/2020] [Indexed: 05/04/2023]
Abstract
Health assessments of wildlife species are becoming increasingly important in an ever-changing environment. Kemp's ridley sea turtles (Lepidochelys kempii; hereafter, Kemp's ridleys) are critically endangered and incur several on-going threats to their population recovery; therefore, it is imperative to advance the understanding of baseline blood analyte data as a diagnostic and monitoring tool. For in-water, trawl-captured, immature Kemp's ridleys (minimum N = 31) from Georgia, USA, the objectives of this study were to (1) establish reference intervals (RIs) for packed cell volume (PCV) and 27 plasma biochemistry analytes and (2) determine length-specific relationships in blood analytes. We observed significant positive correlations between minimum straight carapace length and PCV, amylase, calcium:phosphorus ratio, cholesterol, magnesium, triglycerides, total solids, total protein and all protein fractions (e.g. alpha-, beta- and gamma-globulins); aspartate aminotransferase and chloride showed significant negative relationships. These results suggest that certain blood analytes in Kemp's ridleys change as these animals grow, presumptively due to somatic growth and dietary shifts. The information presented herein, in due consideration of capture technique that may have impacted glucose and potassium concentrations, represents the first report of blood analyte RIs for Kemp's ridley sea turtles established by guidelines of the American Society for Veterinary Clinical Pathology and will have direct applications for stranded individuals in rehabilitative care and for future investigations into the health status of wild individuals from this population.
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Affiliation(s)
- Justin R Perrault
- Loggerhead Marinelife Center, Juno Beach, Florida, 33408, USA
- Corresponding author: Loggerhead Marinelife Center, Juno Beach, Florida, 33408, USA. Tel: 561-627-8280.
| | - Michael D Arendt
- Marine Resources Division, South Carolina Department of Natural Resources, Charleston, South Carolina, 29412, USA
| | - Jeffrey A Schwenter
- Marine Resources Division, South Carolina Department of Natural Resources, Charleston, South Carolina, 29412, USA
| | - Julia L Byrd
- South Atlantic Fish Management Council, North Charleston, South Carolina, 29405, USA
| | - Craig A Harms
- Department of Clinical Sciences and Center for Marine Sciences and Technology, College of Veterinary Medicine, North Carolina State University, Morehead City, North Carolina, 27606, USA
| | - Carolyn Cray
- Division of Comparative Pathology, Department of Pathology and Laboratory Medicine, Miller School of Medicine, University of Miami, Miami, Florida, 33136, USA
| | - Kathryn A Tuxbury
- Animal Health Department, New England Aquarium, Central Wharf, Boston, Massachusetts, 02110, USA
| | - Lawrence D Wood
- Florida Hawksbill Project at the National Save the Sea Turtle Foundation, Fort Lauderdale, Florida, 33308, USA
| | - Nicole I Stacy
- Aquatic, Amphibian, and Reptile Pathology Program, Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, Florida, 32608, USA
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Stacy NI, Lynch JM, Arendt MD, Avens L, Braun McNeill J, Cray C, Day RD, Harms CA, Lee AM, Peden-Adams MM, Thorvalson K, Segars AL, Norton TM. Chronic debilitation in stranded loggerhead sea turtles (Caretta caretta) in the southeastern United States: Morphometrics and clinicopathological findings. PLoS One 2018; 13:e0200355. [PMID: 29990325 PMCID: PMC6039040 DOI: 10.1371/journal.pone.0200355] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 06/25/2018] [Indexed: 12/14/2022] Open
Abstract
Chronically debilitated loggerhead sea turtles (Caretta caretta) (DT) are characterized by emaciation, lethargy, and heavy barnacle coverage. Although histopathological findings associated with this condition have been reported, only limited data is available on health variables with clinical application. The objectives of this study were to 1) to compare morphometrics, clinicopathological variables, and immune functions of DTs to a group of apparently healthy loggerhead turtles to better understand the pathophysiology of the condition and 2) to assess health parameters in live debilitated turtles as they recovered during rehabilitation in order to identify potential prognostic indicators. We examined and sampled 43 DTs stranded from North Carolina to Florida for 47 health variables using standardized protocols to further characterize the condition. DTs were grouped into categories of severity of the condition, and those that survived were sampled at four time points through rehabilitation. All groups and time points were compared among DTs and to clinically healthy loggerhead turtles. Compared to healthy turtles, DTs had significantly lower body condition index, packed cell volume (PCV), total white blood cell (WBC) count, lymphocytes, glucose (Glc), total protein, all protein fractions as determined by electrophoresis, calcium (Ca), phosphorus (P), Ca:P ratio, potassium (K), lymphocyte proliferation, and greater heterophil toxicity and left-shifting, uric acid (UA), aspartate aminotransferase, creatine kinase, lysozyme, and respiratory burst. From admission to recovery, hematology and plasma chemistry data improved as expected. The most informative prognostic indicators, as determined by correlations with a novel severity indicator (based on survival times), were plastron concavity, P, albumin, total solids, UA, lymphocyte proliferation, WBC, K, Glc, Ca:P, and PCV. The results of this study document the wide range and extent of morphometric and metabolic derangements in chronically debilitated turtles. Monitoring morphometrics and clinicopathological variables of these animals is essential for diagnosis, treatment, and prognosis during rehabilitation.
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Affiliation(s)
- Nicole I. Stacy
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States of America
- * E-mail:
| | - Jennifer M. Lynch
- National Institute of Standards and Technology, Chemical Sciences Division, Hollings Marine Laboratory, Charleston, SC, United States of America
| | - Michael D. Arendt
- South Carolina Department of Natural Resources, Charleston, SC, United States of America
| | - Larisa Avens
- NOAA, National Marine Fisheries Service, Beaufort Laboratory, Beaufort, NC, United States of America
| | - Joanne Braun McNeill
- NOAA, National Marine Fisheries Service, Beaufort Laboratory, Beaufort, NC, United States of America
| | - Carolyn Cray
- Division of Comparative Pathology, Department of Pathology & Laboratory Medicine, University of Miami School of Medicine, Miami, FL, United States of America
| | - Rusty D. Day
- National Institute of Standards and Technology, Chemical Sciences Division, Hollings Marine Laboratory, Charleston, SC, United States of America
| | - Craig A. Harms
- North Carolina State University, Center for Marine Science and Technology, Morehead City, NC, United States of America
| | - A. Michelle Lee
- Medical University of South Carolina, Charleston, SC, United States of America
| | | | - Kelly Thorvalson
- South Carolina Aquarium, Charleston, SC, United States of America
| | - Al L. Segars
- South Carolina Department of Natural Resources, Charleston, SC, United States of America
| | - Terry M. Norton
- Georgia Sea Turtle Center, Jekyll Island Authority, GA, United States of America
- St. Catherines Island Foundation, Midway, GA, United States of America
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Arendt MD, Boynton J, Schwenter JA, Byrd JI, Segars AL, Whitaker JD, Parker L, Owens DW, Blanvillain GM, Quattro JM, Roberts MA. Spatial clustering of loggerhead sea turtles in coastal waters of the NW Atlantic Ocean: implications for management surveys. ENDANGER SPECIES RES 2012. [DOI: 10.3354/esr00450] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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11
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Ragland JM, Arendt MD, Kucklick JR, Keller JM. Persistent organic pollutants in blood plasma of satellite-tracked adult male loggerhead sea turtles (Caretta caretta). Environ Toxicol Chem 2011; 30:1549-1556. [PMID: 21509805 DOI: 10.1002/etc.540] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 12/12/2010] [Accepted: 03/10/2011] [Indexed: 05/30/2023]
Abstract
Risks from persistent organic pollutants (POPs) remain largely a mystery for threatened loggerhead sea turtles (Caretta caretta). The present study examines regional-scale POP differences in blood plasma from adult male C. caretta based on movement patterns. Turtles were captured near Port Canaveral, Florida, USA, in April of 2006 and 2007 and fitted with satellite transmitters as part of a National Marine Fisheries Service-funded project. Residents (n = 9) remained near the capture site, whereas transients (n = 10) migrated northward, becoming established in areas largely from south of Pamlico Sound, North Carolina, to north of Cape May, New Jersey, USA. Blood was sampled from the dorsocervical sinus of each turtle and analyzed using gas chromatography-mass spectrometry for organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and toxaphenes. Blood plasma concentrations of OCPs and total PBDEs were elevated in transients (p < 0.05) and in some cases were correlated with turtle size. Migratory adults showed an atypical PBDE congener profile relative to other published studies on wildlife, with PBDE 154 being the dominant congener. Additionally, PCB congener patterns differed between groups, with total PCBs slightly elevated in transients. This supports the idea that foraging location can influence exposure to, and patterns of, POPs in highly mobile species such as C. caretta. Understanding patterns of contamination informs wildlife managers about possible health risks to certain subpopulations. The present study is the first to examine POPs in the rarely studied adult male sea turtle and to couple contaminant measurements with satellite tracking.
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Affiliation(s)
- Jared M Ragland
- Grice Marine Laboratory, College of Charleston, Charleston, South Carolina, USA.
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12
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Day RD, Segars AL, Arendt MD, Lee AM, Peden-Adams MM. Relationship of blood mercury levels to health parameters in the loggerhead sea turtle (Caretta caretta). Environ Health Perspect 2007; 115:1421-8. [PMID: 17938730 PMCID: PMC2022655 DOI: 10.1289/ehp.9918] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2006] [Accepted: 07/11/2007] [Indexed: 05/21/2023]
Abstract
BACKGROUND Mercury is a pervasive environmental pollutant whose toxic effects have not been studied in sea turtles in spite of their threatened status and evidence of immunosuppression in diseased populations. OBJECTIVES In the present study we investigate mercury toxicity in loggerhead sea turtles (Caretta caretta) by examining trends between blood mercury concentrations and various health parameters. METHODS Blood was collected from free-ranging turtles, and correlations between blood mercury concentrations and plasma chemistries, complete blood counts, lysozyme, and lymphocyte proliferation were examined. Lymphocytes were also harvested from free-ranging turtles and exposed in vitro to methylmercury to assess proliferative responses. RESULTS Blood mercury concentrations were positively correlated with hematocrit and creatine phosphokinase activity, and negatively correlated with lymphocyte cell counts and aspartate amino-transferase. Ex vivo negative correlations between blood mercury concentrations and B-cell proliferation were observed in 2001 and 2003 under optimal assay conditions. In vitro exposure of peripheral blood leukocytes to methylmercury resulted in suppression of proliferative responses for B cells (0.1 microg/g and 0.35 microg/g) and T cells (0.7 microg/g). CONCLUSIONS The positive correlation between blood mercury concentration and hematocrit reflects the higher affinity of mercury species for erythrocytes than plasma, and demonstrates the importance of measuring hematocrit when analyzing whole blood for mercury. In vitro immunosuppression occurred at methylmercury concentrations that correspond to approximately 5% of the individuals captured in the wild. This observation and the negative correlation found ex vivo between mercury and lymphocyte numbers and mercury and B-cell proliferative responses suggests that subtle negative impacts of mercury on sea turtle immune function are possible at concentrations observed in the wild.
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Affiliation(s)
- Rusty D Day
- National Institute of Standards and Technology, Hollings Marine Laboratory, Charleston, South Carolina 29412, USA.
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Keller JM, Kannan K, Taniyasu S, Yamashita N, Day RD, Arendt MD, Segars AL, Kucklick JR. Perfluorinated compounds in the plasma of loggerhead and Kemp's ridley sea turtles from the southeastern coast of the United States. Environ Sci Technol 2005; 39:9101-8. [PMID: 16382930 DOI: 10.1021/es050690c] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Perfluorinated compounds (PFCs) have been measured in blood of humans and wildlife and are considered globally distributed contaminants. We examined 12 PFCs in the plasma of 73 loggerhead sea turtles (Caretta caretta) and 6 Kemp's ridley sea turtles (Lepidochelys kempii) captured from inshore waters of Core Sound, North Carolina (NC), and offshore waters of South Carolina, Georgia, and Florida (SC-FL). Perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA) were the dominant compounds, with respective mean concentrations of 11.0 ng/mL and 3.20 ng/mL for loggerhead turtles and 39.4 ng/mL and 3.57 ng/mL for Kemp's ridley turtles. Mean PFOS concentrations were 2- to 12-fold higher than typical mean sigmaPCB concentrations (approximately 5 ng/g wet mass) measured previously in sea turtle blood. More than 79% of the samples had detectable levels of perfluorocarboxylates (PFCAs) with 8-12 carbons, whereas only 17% or less of samples had detectable levels of PFCAs with 6 or 7 carbons. No samples had detectable levels of PFCAs with 4 or 5 carbons. In loggerhead turtles, sigmaPFC concentrations were not influenced by sex (p > 0.05), but were higher in turtles captured from inshore waters of NC than in turtles from offshore waters of SC-FL (p = 0.009). A backward stepwise multiple regression model showed that sigmaPFC concentrations were (1) significantly higher in Kemp's ridley turtles than loggerhead turtles (p < 0.0001), (2) higher in larger turtles (p = 0.018; carapace length used as a proxy for age), and (3) higher in turtles captured toward the north (p = 0.006). These findings suggest that bioaccumulation of PFCs in sea turtles is influenced by species, age, and habitat.
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Affiliation(s)
- Jennifer M Keller
- Hollings Marine Laboratory, National Institute of Standards and Technology, Charleston, South Carolina 29412, USA.
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