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Hays GC, Schofield G, Papazekou M, Chatzimentor A, Katsanevakis S, Mazaris AD. A pulse check for trends in sea turtle numbers across the globe. iScience 2024; 27:109071. [PMID: 38524373 PMCID: PMC10960059 DOI: 10.1016/j.isci.2024.109071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/21/2023] [Accepted: 01/26/2024] [Indexed: 03/26/2024] Open
Abstract
Population declines of vertebrates are common, but rebuilding marine life may be possible. We assessed trends in sea turtle numbers globally, building 61 time series of abundance extending beyond 2015, representing monitoring in >1200 years. Increases were widespread with significant upward trends, no significant change, and significant downward trends in 28, 28, and 5 time series, respectively. For example, annual nest numbers increased between 1980 and 2018 from around 4,000 to 16,000 for green turtles at Aldabra (Seychelles, Indian Ocean) and between 2008 and 2020 from around 500 to 35,000 for loggerhead turtles in Sal (Cape Verde, north Atlantic). However, conservation concerns remain. Major populations may experience declines, such as loggerhead turtles in Oman, while previous upward trends can be reversed, as with green turtles nesting at Tortuguero (Costa Rica, Caribbean). Further, decreases in abundance were evident in several leatherback turtle time series. These concerns show there is no room for complacency for sea turtle conservation.
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Affiliation(s)
- Graeme C. Hays
- School of Life and Environmental Sciences, Deakin University, Geelong, VIC 3280, Australia
| | - Gail Schofield
- School of Biological and Behavioural Sciences, Queen Mary University of London, London E1 4NS, UK
| | - Maria Papazekou
- Department of Ecology, School of Biology, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
| | - Anastasia Chatzimentor
- Department of Ecology, School of Biology, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
| | - Stelios Katsanevakis
- Department of Ecology, School of Biology, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
- Department of Marine Sciences, University of the Aegean, 81100 Mytilene, Greece
| | - Antonios D. Mazaris
- Department of Ecology, School of Biology, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
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2
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Curl LF, Hurst SA, Pomory CM, Lamont MM, Janosik AM. Assessing microplastics contamination in unviable loggerhead sea turtle eggs. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169434. [PMID: 38104820 DOI: 10.1016/j.scitotenv.2023.169434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 12/05/2023] [Accepted: 12/14/2023] [Indexed: 12/19/2023]
Abstract
Sea turtles, in comparison with marine mammals, sea birds, and fishes, are the most affected by microplastics in terms of number of individuals impacted and concentration within each organism. The ubiquitous nature and persistence of microplastics in the environment further compromises sea turtles as many species are currently vulnerable, endangered, or critically endangered. The objective of this study was to quantify microplastic contamination in unviable loggerhead sea turtle eggs (Caretta caretta). Eggs were collected from seven locations along the northwest coast of Florida. A total of 70 nests and 350 eggs were examined. Microplastics (n = 510) were found in undeveloped loggerhead sea turtle eggs across all seven sites, suggesting that maternal transference and/or exchange between the internal and external environment were possible. The frequency found was 7.29 ± 1.83 microplastic pieces per nest and 1.46 ± 0.01 per egg. Microplastics were categorized based on color, shape, size, and type of polymer. The predominant color of microplastics were blue/green (n = 236), shape was fibers (n = 369), and length was 10-300 μm (n = 191). Identified fragments, films, beads and one foam (n = 187) had the most common area of 1-10 μm2 (n = 45). Micro-Fourier Transform Infrared (μ-FTIR) spectroscopy analysis demonstrated that polyethylene (11 %) and polystyrene (7 %) were the main polymer types. For the first time microplastics were found in unviable, undeveloped loggerhead sea turtle eggs collected in northwest Florida. This work provides insight into the distribution patterns of microplastic pollutants in loggerhead sea turtle eggs and may extend to other species worldwide.
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Affiliation(s)
| | | | | | - Margaret M Lamont
- United States Geological Survey, Wetland and Aquatic Research Center, Gainesville, FL, United States of America
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3
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Lasala JA, Macksey MC, Mazzarella KT, Main KL, Foote JJ, Tucker AD. Forty years of monitoring increasing sea turtle relative abundance in the Gulf of Mexico. Sci Rep 2023; 13:17213. [PMID: 37821522 PMCID: PMC10567714 DOI: 10.1038/s41598-023-43651-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 09/26/2023] [Indexed: 10/13/2023] Open
Abstract
Longitudinal data sets for population abundance are essential for studies of imperiled organisms with long life spans or migratory movements, such as marine turtles. Population status trends are crucial for conservation managers to assess recovery effectiveness. A direct assessment of population growth is the enumeration of nesting numbers and quantifying nesting attempts (successful nests/unsuccessful attempts) and emergence success (number of hatchlings leaving the nest) because of the substantial annual variations due to nest placement, predation, and storm activity. We documented over 133,000 sea turtle crawls for 50.9 km of Florida Gulf of Mexico coastline from 1982 to 2021 for a large loggerhead turtle nesting aggregation and a recovering remnant population of green sea turtles. Over time both species have emerged to nest significantly earlier in the year and green sea turtle nesting seasons have extended. Nest counts and hatchling production for both species have significantly increased, but the rate of emergence success of hatchlings leaving nests has not changed for loggerheads and has declined for green sea turtles. Sea level rise and coastal developments undoubtedly influence coastal habitats in the long-term, impacting nest site selection and potential recruitment from the loss of emerged hatchlings. However, the present indications for steady Gulf of Mexico recovery of loggerhead and green sea turtles counter findings of the Florida Atlantic coasts. This study indicates that effective conservation practices can be detected within time scales of 1-2 turtle generations.
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Affiliation(s)
- Jacob Andrew Lasala
- Sea Turtle Conservation and Research Program, Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL, 34236, USA.
| | - Melissa C Macksey
- Sea Turtle Conservation and Research Program, Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL, 34236, USA
| | - Kristen T Mazzarella
- Sea Turtle Conservation and Research Program, Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL, 34236, USA
| | - Kevan L Main
- Sea Turtle Conservation and Research Program, Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL, 34236, USA
| | - Jerris J Foote
- Sea Turtle Conservation and Research Program, Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL, 34236, USA
- Parks, Recreation and Natural Resources, Sarasota County, 1660 Ringling Boulevard, Sarasota, FL, 34236, USA
| | - Anton D Tucker
- Sea Turtle Conservation and Research Program, Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL, 34236, USA
- Marine Science Program, Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Kensington, WA, Australia
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4
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Risoli S, Sarrocco S, Terracciano G, Papetti L, Baroncelli R, Nali C. Isolation and characterization of Fusarium spp. From unhatched eggs of Caretta caretta in Tuscany (Italy). Fungal Biol 2023; 127:1321-1327. [PMID: 37993243 DOI: 10.1016/j.funbio.2023.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 08/25/2023] [Accepted: 08/28/2023] [Indexed: 11/24/2023]
Abstract
Sea Turtle Egg Fusariosis (STEF) is a worldwide emergent fungal disease affecting eggs and causing embryos mortality in turtle's nests such as those of Caretta caretta. It is caused by a complex of species belonging to Fusarium genus, particularly those included in the Fusarium Solani Species Complex (FSSC). During the samplings carried out in summer 2020 along the Tuscany coastlines (Italy), C. caretta eggs showed clinical signs resembling those caused by STEF. A total of 32 fungal isolates were obtained from lesioned eggs whose molecular characterization allowing identifying as belonging to FSSC / Neocosmospora spp., Fusarium oxysporum Species Complex (FOSC) / F. oxysporum and Fusarium nodosum, i.e., fungal genera and speciesincluding also well-known plant pathogens. Isolates inoculated on several plant hosts did not result in any pathogenic activity but F. nodosum causing, on wheat spikes, disease symptoms.This is the first time F. nodosum has been isolated from portions of eggs showing evident signs of fungal infection. This work represents the first report of Fusarium spp. isolated from C. caretta eggs showing lesions resembling those caused by STEF on Tuscan coast thus posing a significant concern to loggerhead sea turtle conservation also in this region.
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Affiliation(s)
- Samuele Risoli
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80 Pisa 56124, Italy; University School for Advanced Studies IUSS, Palazzo Del Broletto, Piazza Della Vittoria 15, Pavia, 27100 Italy
| | - Sabrina Sarrocco
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80 Pisa 56124, Italy.
| | - Giuliana Terracciano
- Istituto Zooprofilattico Sperimentale Delle Regioni Lazio e Toscana, SS Dell' Abetone e Del Brennero 4, Pisa 56123 Italy
| | - Luana Papetti
- tartAmare, Centro Recupero Tartarughe Marine, via Bramante n. 83 Marina di Grosseto, Italy
| | - Riccardo Baroncelli
- Department of Agricultural and Food Sciences (DISTAL), University of Bologna, Viale Giuseppe Fanin 42 Bologna 40127, Italy
| | - Cristina Nali
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80 Pisa 56124, Italy
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5
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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] [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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6
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Lamont MM, Ingram D, Baker T, Weigel M, Shamblin BM. Confirmation of significant sea turtle nesting activity on a remote island chain in the Gulf of Mexico. Ecol Evol 2023; 13:e10448. [PMID: 37608924 PMCID: PMC10441180 DOI: 10.1002/ece3.10448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/24/2023] [Accepted: 08/06/2023] [Indexed: 08/24/2023] Open
Abstract
Globally, six of the seven sea turtle species are threatened or endangered and as such, monitoring reproductive activity for these species is necessary for effective population recovery. Remote beaches provide a challenge to conducting these surveys, which often results in data gaps that can hamper management planning. Throughout the summer of 2022, aerial surveys were conducted over the Chandeleur Islands in the Gulf of Mexico. Turtle crawls were photographed for subsequent review by 10 expert observers. Whenever possible, ground surveys were conducted, and samples of unhatched eggs or dead hatchlings were collected. A summary of historic reports of sea turtle nesting activity at this site was also compiled. On 11 days between May 4, 2022, and July 30, 2022, photographs of 55 potential sea turtle crawls were taken. Observers identified 54 of those as being made by a sea turtle. There was high-to-moderate certainty that 16 of those crawls were nests, that 14 were made by loggerheads, and that two were made by Kemp's ridleys. Observers were least certain of species identification when surveys were conducted during rainy weather. Genetic analyses based on mitochondrial and nuclear DNA were conducted on samples from five nests and those analyses confirmed that three nests were laid by Kemp's ridleys and two were laid by loggerheads. Historic records from the Chandeleur Islands substantiate claims that the Chandeleurs have supported sea turtle nesting activity for decades; however, the consistency of this activity remains unknown. Our aerial surveys, particularly when coupled with imaging, were a useful tool for documenting nesting activity on these remote islands. Future monitoring programs at this site could benefit from a standardized aerial survey program with a seaplane so trends in nesting activity could be determined particularly as the beach undergoes restoration.
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Affiliation(s)
- Margaret M. Lamont
- Wetland and Aquatic Research CenterU.S. Geological SurveyGainesvilleFloridaUSA
| | - Dianne Ingram
- Deepwater Horizon Gulf Restoration OfficeU.S. Fish and Wildlife ServiceFairhopeAlabamaUSA
| | - Todd Baker
- Louisiana Coastal Protection and Restoration AuthorityBaton RougeLouisianaUSA
| | - Matt Weigel
- Louisiana Department of Wildlife and FisheriesBaton RougeLouisianaUSA
| | - Brian M. Shamblin
- Warnell School of Forestry and Natural ResourcesUniversity of GeorgiaAthensGeorgiaUSA
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7
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Catron S, Roth S, Zumpano F, Bintz J, Fordyce JA, Lenhart S, Miller DL, Wyneken J. Modeling the impacts of temperature during nesting seasons on Loggerhead (Caretta caretta) Sea Turtle populations in South Florida. Ecol Modell 2023. [DOI: 10.1016/j.ecolmodel.2023.110363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
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8
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Hatch JM, Murray KT, Patel S, Smolowitz R, Haas HL. Evaluating simple measures of spatial-temporal overlap as a proxy for encounter risk between a protected species and commercial fishery. FRONTIERS IN CONSERVATION SCIENCE 2023. [DOI: 10.3389/fcosc.2023.1118418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023] Open
Abstract
Spatial and temporal assessments of overlap are becoming increasingly popular as indicators of encounter risk. The overlap in distributions between protected species and commercial fishing effort is of interest for reducing bycatch. We explored overlap between the U.S. Atlantic sea scallop fishery and loggerhead turtles (Caretta caretta) using 2 metrics, and we assessed the ability of one of those metrics to track estimated fishery interactions over time. Moderate overlap occurred between June - September; mild overlap in the spring (May) and fall (October - November); and relatively little overlap from December to April. Qualitatively, there appeared to be some correspondence between the overlap values averaged across months for each calendar year and published annual loggerhead interaction estimates with fisheries, but the predictive performance of the overlap metric was low. When data on the relative distributions of commercial fishing effort and protected species are available, simple measures of spatial and temporal overlap can provide a quick and cost-effective way to identify when and where bycatch is likely to occur. In this case study, however, overlap was limited in helping to understand the relative susceptibility of protected species to commercial fishing (i.e., magnitude of interactions). We therefore caution against using overlap as a meaningful predictor of absolute risk unless there is direct evidence to suggest a relationship.
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9
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Del Monte-Luna P, Nakamura M, Guzmán-Hernández V, Cuevas E, López-Castro MC, Arreguín-Sánchez F. Multidecadal fluctuations in green turtle hatchling production related to climate variability. Sci Rep 2023; 13:1542. [PMID: 36707700 PMCID: PMC9883438 DOI: 10.1038/s41598-023-28574-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 01/20/2023] [Indexed: 01/28/2023] Open
Abstract
The state of Campeche, Mexico, harbors one of the largest green turtle (Chelonia mydas) rookeries of the Wider Caribbean Region. Since the 1970s, harvesting of this population was common practice, but it has since ceased, and the population is rebounding as a consequence. In this rookery, during the past 37 years (1984-2020), the positive relationship between the annual number of nesting females and the number of hatchlings they produce has revealed a long-term population signal that we postulate could be related to environmental factors. To investigate this relationship more deeply, we adopt a stock-recruitment (SR) approach, which is commonly used in fisheries. Regression analysis methods for the SR relationship, including a dynamic version of the model that incorporates the effect of sea surface temperature, show that the number of recruits produced and the number of hatchlings per unit nester were significantly and inversely correlated with a 26-year cycle of the Atlantic Multidecadal Oscillation (AMO) with a three year lag. A possible explanation for this finding is that environmental conditions during warming periods of the 26-year AMO cycle may negatively affect hatchling production by altering the nest moisture content during the incubation period, and increasing embryonic mortality, while the annual female abundance at nesting beaches may decrease due to trophic effects. The time series of abundance corresponding to other population units of green turtles as well as other species of sea turtles in the Gulf of Mexico present a similar behavior to that evaluated here, suggesting a basin-wide environmental effect.
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Affiliation(s)
- Pablo Del Monte-Luna
- Departamento de Pesquerías y Biología Marina, Instituto Politécnico Nacional, 23096, La Paz, Baja California Sur, Mexico.
| | - Miguel Nakamura
- Departamento de Probabilidad y Estadística, Centro de Investigación en Matemáticas, 36023, Guanajuato, Guanajuato, Mexico.
| | - Vicente Guzmán-Hernández
- Área de Protección de Flora y Fauna Laguna de Términos, Comisión Nacional de Áreas Naturales Protegidas, 24140, Ciudad del Carmen, Campeche, Mexico
| | - Eduardo Cuevas
- Recursos del Mar, CONACYT-Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, 97310, Mérida, Yucatán, Mexico
| | - Melania C López-Castro
- Programa para la Conservación de Tortugas Marinas, Pronatura Península de Yucatán, A.C., 97205, Mérida, Yucatán, Mexico
| | - Francisco Arreguín-Sánchez
- Departamento de Pesquerías y Biología Marina, Instituto Politécnico Nacional, 23096, La Paz, Baja California Sur, Mexico
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10
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McGinley E, Cogley A, Palmer L, McCaul P, Longo L, Silvennoinen J, Martin A, Gomez J, Bachmaier S, Mackey M, Kao C, Eastman S, Eastman C. Marina Observation of Sea Turtles: Establishing a Database of Intracoastal Waterway Green Sea Turtles in Northeast Florida. Animals (Basel) 2023; 13:ani13020279. [PMID: 36670819 PMCID: PMC9854553 DOI: 10.3390/ani13020279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/09/2023] [Accepted: 01/11/2023] [Indexed: 01/15/2023] Open
Abstract
As conservation efforts regarding green sea turtles, Chelonia mydas, continue, it is imperative to document behaviors and foraging habits/habitats of understudied populations. We have conducted an 18-month study dedicated to photographing the local population feeding alongside floating docks within the Guana Tolomato Matanzas estuary to determine the capability of matching head scale patterns efficiently through a pattern matching program: HotSpotter. To date, 195 unique sea turtles have been identified between two different marinas located in St. Augustine, FL. Of these, 98 were spotted more than once, with 39 of them being "tracked" for longer than a year. Temperature trends were also monitored in conjunction, showing that more individuals appeared during the warmer months of the year. The evidence, overall, indicates that these locations host a resident population of green sea turtles, leading to the need for a discussion on potential threats originating from the usage of these marinas by humans.
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Affiliation(s)
- Edward McGinley
- Department of Natural Sciences, Flagler College, St. Augustine, FL 32084, USA
- Correspondence:
| | - Avery Cogley
- Department of Natural Sciences, Flagler College, St. Augustine, FL 32084, USA
| | - Leslie Palmer
- Department of Natural Sciences, Flagler College, St. Augustine, FL 32084, USA
| | - Patricia McCaul
- Department of Natural Sciences, Flagler College, St. Augustine, FL 32084, USA
| | - Lilli Longo
- Department of Natural Sciences, Flagler College, St. Augustine, FL 32084, USA
| | | | - Angela Martin
- Department of Natural Sciences, Flagler College, St. Augustine, FL 32084, USA
| | - Josalyn Gomez
- Department of Natural Sciences, Flagler College, St. Augustine, FL 32084, USA
| | - Sydney Bachmaier
- Department of Natural Sciences, Flagler College, St. Augustine, FL 32084, USA
| | - Michaela Mackey
- Department of Natural Sciences, Flagler College, St. Augustine, FL 32084, USA
| | - Chris Kao
- Department of Mathematics and Technology, Flagler College, St. Augustine, FL 32084, USA
| | - Scott Eastman
- Office of Resilience and Coastal Protection, Florida Department of Environmental Protection, St. Augustine, FL 32080, USA
| | - Catherine Eastman
- Whitney Laboratory, University of Florida, St. Augustine, Fl 32080, USA
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11
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Salvarani PI, Vieira LR, Rendón-von Osten J, Morgado F. Hawksbill Sea Turtle ( Eretmochelys imbricata) Blood and Eggs Organochlorine Pesticides Concentrations and Embryonic Development in a Nesting Area (Yucatan Peninsula, Mexico). TOXICS 2023; 11:50. [PMID: 36668776 PMCID: PMC9865186 DOI: 10.3390/toxics11010050] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/21/2022] [Accepted: 12/26/2022] [Indexed: 06/17/2023]
Abstract
Environmental contaminants with chemical origins, such as organochlorine pesticides (OCPs) have major impacts on the health of marine animals, including sea turtles, due to the bioaccumulation of those substances by transference throughout the food chain. The effects of environmental pollution on the health of marine turtles are very important for management strategies and conservation. During recent decades, the south Gulf of Mexico and the Yucatan Peninsula have suffered from increasingly frequent disturbances from continental landmasses, river systems, urban wastewater runoff, port areas, tourism, industrial activities, pesticides from agricultural use, and other pollutants, such as metals, persistent organic pollutants (POPs) and hydrocarbons (from the oil industry activities), which contaminate water and sediments and worsen the environmental quality of the marine ecosystem in this region. In this study, we assessed the concentrations of OCPs in the blood and eggs of 60 hawksbill turtles (Eretmochelys imbricata) nesting at the Punta Xen turtle camp, and their effects on the nesting population's reproductive performance: specifically, maternal transfer and embryonic development were analyzed. Hematologic characteristics, including packed cell volume, white blood cell count, red blood cell count, and haemoglobin levels, and plasma chemistry values, including creatinine, blood urea nitrogen, uric acid, triglyceride, total cholesterol and glucose, were also measured. The general health of the turtles in this study, as well as their levels of urea, serum creatinine, glucose, uric, acid, cholesterol, and triglyceride, fell within normal ranges and was similar to other normal values, which could indicate the turtles' good energy levels and body conditions for nest-building activity, with all of the turtles able to successfully come ashore to nest. All the same, the obtained results also indicate that OCPs affect the nesting and reproductive performance of the hawksbill turtles, as well as their fertility and the development of the population of eggs and reproductive performance, specifically in terms of maternal transference and embryonic development. There were significant differences in the concentrations of OCPs (ΣHCHs and ΣDienes) between maternal blood and eggs, indicating that these chemicals are transferred from nesting females to eggs and, ultimately, to hatchlings. OCPs may, therefore, have an effect on the health and reproductive performance of hawksbill turtles, both in terms of their fertility and egg development. Conservation strategies need to be species-specific, due to differences in feeding, and address the reasons for any decline, focusing on regional assessments. Thus, accurate and comparable monitoring data are necessary, which requires the standardization of monitoring protocols.
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Affiliation(s)
- Patricia I. Salvarani
- Department of Biology and the Centre for Environmental and Marine Studies (CESAM), University of Aveiro, 3810-193 Aveiro, Portugal
| | - Luis R. Vieira
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 2250-208 Matosinhos, Portugal
- School of Medicine and Biomedical Sciences (ICBAS), University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Jaime Rendón-von Osten
- Instituto Epomex, Universidad Autónoma de Campeche, Av Augustin de Melgar y Juan de la Barrera s/n, Campeche 24039, Mexico
| | - Fernando Morgado
- Department of Biology and the Centre for Environmental and Marine Studies (CESAM), University of Aveiro, 3810-193 Aveiro, Portugal
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12
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López-Castro MC, Cuevas E, Guzmán Hernández V, Raymundo Sánchez Á, Martínez-Portugal RC, Reyes DJL, Chio JÁB. Trends in Reproductive Indicators of Green and Hawksbill Sea Turtles over a 30-Year Monitoring Period in the Southern Gulf of Mexico and Their Conservation Implications. Animals (Basel) 2022; 12:ani12233280. [PMID: 36496800 PMCID: PMC9739169 DOI: 10.3390/ani12233280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 11/27/2022] Open
Abstract
Long-term monitoring programs of species at risk are efficacious tools to assess population changes, evaluate conservation strategies, and improve management practices to ensure populations reach levels at which they can fulfill their ecological roles. For sea turtles, annual nesting beach surveys are the most accessible method to estimating the population abundance and reproductive output, especially when these are done in primary nesting sites. However, little data exist on the long-term assessment of these parameters. Here, we present the trends of the nest abundance, female size, hatching, and emergence success of hawksbill (Eretmochelys imbricata) and green (Chelonia mydas) turtles at key nesting beaches in the southern Gulf of Mexico over 31 years (from 1990 to 2021). The nest abundance showed an increasing trend in both species as a result of the sustained protection and conservation effort, but there was no significant temporal trend in the annual female size, clutch size, hatching, and emergence success. However, these indicators showed decreasing mean values over the last decade and should be closely monitored. We suggest these decreases link to the combined effects of ocean warming and anthropogenic pressures affecting the sea turtle foraging grounds. Aside from protecting key nesting sites, protecting and restoring crucial foraging habitats should be an immediate priority requiring international cooperation.
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Affiliation(s)
- Melania C. López-Castro
- Pronatura Península de Yucatán, A.C., Programa para la Conservación de la Tortuga Marina, Merida 97205, Yucatán, Mexico
- Correspondence:
| | - Eduardo Cuevas
- Departamento de Recursos del Mar, Consejo Nacional de Ciencia y Tecnología—Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Unidad Mérida, Merida 97310, Yucatán, Mexico
| | - Vicente Guzmán Hernández
- Comisión Nacional de Áreas Naturales Protegidas, Área de Protección de Flora y Fauna Laguna de Términos, Ciudad del Carmen 24129, Campeche, Mexico
| | - Ángeles Raymundo Sánchez
- Département des Sciences du Bois et de la Forêt, Faculté de Foresterie et de Géomatique, Université Laval, Quebec, QC G1V 0A6, Canada
| | - Rosa C. Martínez-Portugal
- Comisión Nacional de Áreas Naturales Protegidas, Parque Nacional Sistema Arrecifal Veracruzano, Veracruz 91919, Veracruz, Mexico
| | - Diana J. Lira Reyes
- Pronatura Península de Yucatán, A.C., Programa para la Conservación de la Tortuga Marina, Merida 97205, Yucatán, Mexico
| | - Jorge Ángel Berzunza Chio
- Secretaría de Medio Ambiente, Biodiversidad, Cambio Climático y Energía de Campeche, Subdirección de Vida Silvestre, San Francisco de Campeche 24095, Campeche, Mexico
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Heppell SS, Wyneken J, Heppell SA. A morphologist, a modeler, and an endocrinologist consider sea turtle sex ratios in a changing climate. Some wine was involved. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.952432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Because the sex of sea turtles is determined by temperature during embryonic development, many populations are vulnerable to increased bias in primary sex ratios as global temperatures rise. Higher temperatures produce more females, and some populations are already showing years with all-female offspring production. But because sea turtles take decades to mature and have long adult lifespans, these primary sex ratio biases can take years to impact adult sex ratios, and the males from cohorts that are produced during cooler years may compensate for the sex ratio bias if they can breed more frequently and with multiple females. To date, little is known about male sea turtle reproductive behavior, making predictions of sex ratio skew impacts highly speculative. We used data from southern Florida loggerhead sea turtle nests to parameterize a simple population model to explore the effects of an increase in the proportion of female hatchlings over time on population trends, effective population size (Ne), and quasi-extinction probability. We also tested the effects of increasing the frequency of relatively high male production years to simulate potential mitigation strategies. While heuristic rather than predictive, our results expectedly show a rise in nest counts due to the increase in females over time, followed by population decline as males become limiting. Population collapse due to increased female bias will take many decades to occur, but sex ratio skew can have large impacts on Ne, and thus increase the potential for inbreeding. An increase in the frequency of male production years, even just one additional “good male year” per decade, can help mitigate these outcomes if the rate of feminization is not too rapid. Male breeding frequency and mating success are critical drivers of the results and must be prioritized for research.
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Mollenhauer R, Lamont MM, Foley A. Long‐term apparent survival of a cold‐stunned subpopulation of juvenile green turtles. Ecosphere 2022. [DOI: 10.1002/ecs2.4221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Affiliation(s)
- Robert Mollenhauer
- U.S. Geological Survey Wetland and Aquatic Research Center Gainesville Florida USA
| | - Margaret M. Lamont
- U.S. Geological Survey Wetland and Aquatic Research Center Gainesville Florida USA
| | - Allen Foley
- Florida Fish and Wildlife Conservation Commission, Jacksonville Field Laboratory Fish and Wildlife Research Institute Jacksonville Florida USA
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15
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Gravelle J, Wyneken J. Resilient Eggs: Highly Successful Loggerhead Sea Turtle Nesting Sites Vary in Their Characteristics. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.853835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Sea turtle nest success, defined as the number of eggs in a nest that successfully hatch and emerge, is closely linked to environmental conditions. Interacting biotic and abiotic factors influence hatching and hatchling emergence success. To date, combinations of multiple factors interacting together, which result in highly successful sea turtle nests are not well understood. Using 25 years of historic nest data and local expert experience, we identified five historically successful loggerhead (Caretta caretta) nesting beaches (hotspots) along the Florida (United States) Atlantic coast and measured nest environments along with the nest success. Principal component analysis was used to reduce 12 environmental variables so that the relative contributions of sand characteristics, nest temperatures, sand moisture, and nest location were considered. The nest environments differed among nesting beaches and were broadly segregated into two distinct climates: subtropical (hot and humid) and warm-temperate (warm and dry). We found that nests at subtropical sites, compared with warm-temperate sites, were characterized by environmental gradients in contrasting ways. Nest locations were predominantly mid-beach in subtropical sites but clustered at higher elevations and closer to the base of the dune at warm-temperate climate sites. Collectively, highly successful nest hotspots represent a mosaic of abiotic factors providing conditions that promote successful hatching and emergence. This new perspective on consistently successful loggerhead nesting beach traits demonstrate that the key traits of sea turtle nesting habitat vary with prevailing climate type and should be managed accordingly.
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Kettemer LE, Biastoch A, Wagner P, Coombs EJ, Penrose R, Scott R. Oceanic drivers of juvenile sea turtle strandings in the UK. ENDANGER SPECIES RES 2022. [DOI: 10.3354/esr01184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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17
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Lamont MM, Mollenhauer R, Foley AM. Capture vulnerability of sea turtles on recreational fishing piers. Ecol Evol 2022; 12:e8473. [PMID: 35127015 PMCID: PMC8796914 DOI: 10.1002/ece3.8473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/27/2021] [Accepted: 11/29/2021] [Indexed: 11/11/2022] Open
Abstract
Capture vulnerability of commercial and recreational fishes has been associated with behavioral, morphological, and life-history traits; however, relationships with non-target species, such as sea turtles, have not been adequately studied. We examined species composition, timing of captures, morphological variables including body size and head width, and body condition of sea turtles captured from a recreational fishing pier in the northern Gulf of Mexico and of sea turtles captured in the waters adjacent to the pier. From 2014 to 2019, 148 net captures and 112 pier captures of three sea turtle species were documented. Green turtles were captured most frequently in the net and on the pier. Turtles captured from the pier were larger than those captured in the net. There was no difference in head width between net-caught and pier-caught turtles; however, small sample sizes limited those comparisons. The body condition index was lower for pier-caught than net-caught Kemp';s ridleys but did not differ with green turtles or loggerheads. Differences were also observed in the timing of capture on the pier as compared to in the net. Finally, the relationship between size, body condition, and pier-capture vulnerability suggests these are complex interactions. Mortality of sea turtles captured from fishing piers could be selecting against bolder individuals, which may result in changes in sea turtle population demographics over a long time period.
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Affiliation(s)
- Margaret M Lamont
- U.S. Geological Survey Wetland and Aquatic Research Center Gainesville Florida USA
| | - Robert Mollenhauer
- U.S. Geological Survey Wetland and Aquatic Research Center Gainesville Florida USA
| | - Allen M Foley
- Florida Fish and Wildlife Conservation Commission Jacksonville Field Laboratory Fish and Wildlife Research Institute Jacksonville Florida USA
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18
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Ataman A, Gainsbury AM, Manire CA, Hoffmann SL, Page-Karjian A, Hirsch SE, Polyak MMR, Cassill DL, Aoki DM, Fraser KM, Klingshirn S, Stoll JA, Perrault JR. Evaluating prevalence of external injuries on nesting loggerhead sea turtles Caretta caretta in southeastern Florida, USA. ENDANGER SPECIES RES 2021. [DOI: 10.3354/esr01149] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Sea turtles face both anthropogenic and natural threats including boat strikes, fisheries, pollution, and predator attacks. Injuries from anthropogenic sources are more common than naturally caused injuries. The goal of this study was to determine prevalence and cause (e.g. boat strike, entanglement, hook, shark bite) of injuries on nesting loggerhead sea turtles Caretta caretta on Juno and Jupiter beaches, Florida, USA. During the 2019 and 2020 nesting seasons, 450 loggerhead females were examined for external injuries. Injuries were categorized by anatomic location, condition, and cause. We found that 24% of loggerheads had at least 1 injury. Of the 111 injuries found on 107 nesting females, 88% were healed, 9% were partially healed with some scarred tissue, and 3% were fresh injuries. Most injuries (55%) were lateral injuries on the carapace or appendages. We were able to attribute 60 injuries to a specific cause. Boat strikes accounted for 75% of the 60 injuries, shark bites accounted for 15%, fishing hooks accounted for 7%, and entanglements accounted for the remaining 3%. This study provides new insight into the prevalence of anthropogenic injuries relative to natural injuries in loggerhead sea turtles nesting in the most densely nested beach in the Western Hemisphere and can be used to improve conservation management plans through implementation of fishing and/or boating restrictions in the nesting and foraging areas most commonly frequented by sea turtles.
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Affiliation(s)
- A Ataman
- Department of Integrative Biology, University of South Florida St. Petersburg, St. Petersburg, Florida 33701, USA
| | - AM Gainsbury
- Department of Integrative Biology, University of South Florida St. Petersburg, St. Petersburg, Florida 33701, USA
| | - CA Manire
- Loggerhead Marinelife Center, Juno Beach, Florida 33408, USA
| | - SL Hoffmann
- Applied Biological Services, Biomark Inc., Boise, Idaho 83702, USA
| | - A Page-Karjian
- Florida Atlantic University, Harbor Branch Oceanographic Institute, Fort Pierce, Florida 34946, USA
| | - SE Hirsch
- Loggerhead Marinelife Center, Juno Beach, Florida 33408, USA
| | - MMR Polyak
- Loggerhead Marinelife Center, Juno Beach, Florida 33408, USA
| | - DL Cassill
- Department of Integrative Biology, University of South Florida St. Petersburg, St. Petersburg, Florida 33701, USA
| | - DM Aoki
- Loggerhead Marinelife Center, Juno Beach, Florida 33408, USA
- Florida Atlantic University, Harbor Branch Oceanographic Institute, Fort Pierce, Florida 34946, USA
| | - KM Fraser
- Loggerhead Marinelife Center, Juno Beach, Florida 33408, USA
| | - S Klingshirn
- Loggerhead Marinelife Center, Juno Beach, Florida 33408, USA
- Florida Atlantic University, Harbor Branch Oceanographic Institute, Fort Pierce, Florida 34946, USA
| | - JA Stoll
- Department of Environmental Conservation, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - JR Perrault
- Loggerhead Marinelife Center, Juno Beach, Florida 33408, USA
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19
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Agyekumhene A, Yankson P, Stemle L, Allman P. Sea Turtle Nesting Activity in Ghana, West Africa. CHELONIAN CONSERVATION AND BIOLOGY 2021. [DOI: 10.2744/ccb-1487.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Andrews Agyekumhene
- Department of Marine and Fisheries Sciences, University of Ghana, PO Box LG 99, Legon, Accra, Ghana []
| | - Prince Yankson
- Ghana Turtle Research Project, PO Box WB 202, Winneba, Ghana []
| | - Leyna Stemle
- Department of Biology, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146 USA []
| | - Phil Allman
- Department of Biological Sciences, Florida Gulf Coast University, 10501 FGCU Boulevard South, Fort Myers, Florida 33965 USA []
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20
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Abstract
AbstractOne of the largest nesting colonies of the Vulnerable loggerhead sea turtle Caretta caretta is in Cabo Verde. Here we present the first comprehensive study of loggerhead turtle nesting on the island of Maio in Cabo Verde. During 2016–2019 we monitored 38 km of undeveloped sandy beaches that have minimal artificial lighting and where all nesting on Maio takes place. We counted 4,063 nests in 2016, 5,429 in 2017, 14,364 in 2018 and 7,937 in 2019. The estimated total number of females was 1,016, 1,357, 3,591 and 1,984 in each of these years, respectively. Our findings suggest there are more loggerhead turtles nesting in Cabo Verde than previously estimated, and that this could be the species’ largest nesting subpopulation (followed by Florida, USA and Oman). The inter-annual hatching success (the proportion of eggs producing hatchlings) was 29–38% for the whole island but varied between sites. Our study of 250 clutches showed that flooding affected 38–61% and predation by crabs 40–42%, with hatching success on different beaches in the range of 1–59%. Poaching of eggs was rare (< 2% of clutches), but dogs predated 68.4% of all clutches on the beach nearest the largest human settlement. We evaluated different nest management strategies at multiple sites and estimated productivity of hatchlings (the number of hatchlings that would reach the sea for each management strategy), finding that hatcheries are not always the best option for nest management. As the beaches on Maio are relatively undisturbed, and there is a high abundance and density of turtle nests, the island should be protected as a globally important site for the conservation of the loggerhead turtle, and of coastal biodiversity more broadly.
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21
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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. GLOBAL CHANGE BIOLOGY 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] [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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22
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Critical In-Water Habitats for Post-Nesting Sea Turtles from the Southern Gulf of Mexico. JOURNAL OF MARINE SCIENCE AND ENGINEERING 2021. [DOI: 10.3390/jmse9080793] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Marine turtles are globally endangered species that spend more than 95% of their life cycle in in-water habitats. Nevertheless, most of the conservation, recovery and research efforts have targeted the on-land habitats, due to their easier access, where adult females lay their eggs. Targeting the large knowledge gaps on the in-water critical habitats of turtles, particularly in the Large Marine Ecosystem Gulf of Mexico, is crucial for their conservation and recovery in the long term. We used satellite telemetry to track 85 nesting females from their beaches after they nested to identify their feeding and residency habitats, their migratory corridors and to describe the context for those areas. We delimited major migratory corridors in the southern Gulf of Mexico and West Caribbean and described physical features of internesting and feeding home ranges located mainly around the Yucatan Peninsula and Veracruz, Mexico. We also contributed by describing general aggregation and movement patterns for the four marine turtle species in the Atlantic, expanding the knowledge of the studied species. Several tracked individuals emigrated from the Gulf of Mexico to as far as Nicaragua, Honduras, and the Bahamas. This information is critical for identifying gaps in marine protection and for deciphering the spatial connectivity in large ocean basins, and it provides an opportunity to assess potential impacts on marine turtle populations and their habitats.
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Phillips KF, Stahelin GD, Chabot RM, Mansfield KL. Long‐term trends in marine turtle size at maturity at an important Atlantic rookery. Ecosphere 2021. [DOI: 10.1002/ecs2.3631] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Katrina F. Phillips
- Department of Biology Marine Turtle Research Group University of Central Florida 4000 Central Florida Blvd., Bldg. 20BIO301 Orlando Florida32816USA
| | - Gustavo D. Stahelin
- Department of Biology Marine Turtle Research Group University of Central Florida 4000 Central Florida Blvd., Bldg. 20BIO301 Orlando Florida32816USA
| | - Ryan M. Chabot
- Department of Biology Marine Turtle Research Group University of Central Florida 4000 Central Florida Blvd., Bldg. 20BIO301 Orlando Florida32816USA
- Inwater Research Group 4160 NE Hyline Drive Jensen Beach Florida34957USA
| | - Katherine L. Mansfield
- Department of Biology Marine Turtle Research Group University of Central Florida 4000 Central Florida Blvd., Bldg. 20BIO301 Orlando Florida32816USA
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Silver-Gorges I, Ingels J, dos Santos GAP, Valdes Y, Pontes LP, Silva AC, Neres PF, Shantharam A, Perry D, Richterkessing A, Sanchez-Zarate S, Acevedo L, Gillis AJ, Ceriani SA, Fuentes MMPB. Epibionts Reflect Spatial and Foraging Ecology of Gulf of Mexico Loggerhead Turtles (Caretta caretta). Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.696412] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Sea turtles are exposed to numerous threats during migrations to their foraging grounds and at those locations. Therefore, information on sea turtle foraging and spatial ecology can guide conservation initiatives, yet it is difficult to directly observe migrating or foraging turtles. To gain insights into the foraging and spatial ecology of turtles, studies have increasingly analyzed epibionts of nesting turtles, as epibionts must overlap spatially and ecologically with their hosts to colonize successfully. Epibiont analysis may be integrated with stable isotope information to identify taxa that can serve as indicators of sea turtle foraging and spatial ecology, but few studies have pursued this. To determine if epibionts can serve as indicators of foraging and spatial ecology of loggerhead turtles nesting in the northern Gulf of Mexico we combined turtle stable isotope and taxonomic epibiont analysis. We sampled 22 individual turtles and identified over 120,000 epibiont individuals, belonging to 34 macrofauna taxa (>1 mm) and 22 meiofauna taxa (63 μm–1 mm), including 111 nematode genera. We quantified epidermis δ13C and δ15N, and used these to assign loggerhead turtles to broad foraging regions. The abundance and presence of macrofauna and nematodes did not differ between inferred foraging regions, but the presence of select meiofauna taxa differentiated between three inferred foraging regions. Further, dissimilarities in macrofauna, meiofauna, and nematode assemblages corresponded to dissimilarities in individual stable isotope values within inferred foraging regions. This suggests that certain epibiont taxa may be indicative of foraging regions used by loggerhead turtles in the Gulf of Mexico, and of individual turtle foraging and habitat use specialization within foraging regions. Continued sampling of epibionts at nesting beaches and foraging grounds in the Gulf of Mexico and globally, coupled with satellite telemetry and/or dietary studies, can expand upon our findings to develop epibionts as efficient indicators of sea turtle foraging and spatial ecology.
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Rice N, Hirama S, Witherington B. High frequency of micro- and meso-plastics ingestion in a sample of neonate sea turtles from a major rookery. MARINE POLLUTION BULLETIN 2021; 167:112363. [PMID: 33895595 DOI: 10.1016/j.marpolbul.2021.112363] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 04/06/2021] [Accepted: 04/07/2021] [Indexed: 06/12/2023]
Abstract
We studied marine litter ingestion in 380 neonate sea turtles that washed ashore dead onto Florida's central Atlantic coast (USA) following onshore winds. Our sample of "washbacks" included 284 loggerheads (Caretta caretta), 95 green turtles (Chelonia mydas), and one hawksbill (Eretmochelys imbricata). Of these, 78.7% had ingested plastics and 45.3% had ingested tar. There was a significant relationship between turtles' carapace length and total mass of ingested plastic. Ingested plastics included microplastics (<5 mm) and larger sizes up to 25% of carapace length. Washbacks' body condition indices were significantly poorer than condition indices of wild turtles captured at sea. Washbacks showed a negative association between plastic load and body condition index, evidence that high plastic loads resulted in diminished nutrition, with possible effects on somatic growth, stage duration, and survivorship. Evidence points to plastics ingestion being an important source of population-level effects in neonate sea turtles.
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Affiliation(s)
- Nikia Rice
- Mission Clean Beaches Inc., 1253 Haulover St., Palm Bay, FL 32908, USA.
| | - Shigetomo Hirama
- Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, 1105 Southwest Williston Road, Gainesville, FL 32601, USA
| | - Blair Witherington
- Inwater Research Group, Inc., 4160 NE Hyline Dr., Jensen Beach, FL 34957, USA
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26
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Ariano-Sánchez D, Muccio C, Rosell F, Reinhardt S. Are trends in Olive Ridley sea turtle (Lepidochelys olivacea) nesting abundance affected by El Niño Southern Oscillation (ENSO) variability? Sixteen years of monitoring on the Pacific coast of northern Central America. Glob Ecol Conserv 2020. [DOI: 10.1016/j.gecco.2020.e01339] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Putman NF, Hawkins J, Gallaway BJ. Managing fisheries in a world with more sea turtles. Proc Biol Sci 2020; 287:20200220. [PMID: 32605516 DOI: 10.1098/rspb.2020.0220] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
For decades, fisheries have been managed to limit the accidental capture of vulnerable species and many of these populations are now rebounding. While encouraging from a conservation perspective, as populations of protected species increase so will bycatch, triggering management actions that limit fishing. Here, we show that despite extensive regulations to limit sea turtle bycatch in a coastal gillnet fishery on the eastern United States, the catch per trip of Kemp's ridley has increased by more than 300% and green turtles by more than 650% (2001-2016). These bycatch rates closely track regional indices of turtle abundance, which are a function of increased reproductive output at distant nesting sites and the oceanic dispersal of juveniles to near shore habitats. The regulations imposed to help protect turtles have decreased fishing effort and harvest by more than 50%. Given uncertainty in the population status of sea turtles, however, simply removing protections is unwarranted. Stock-assessment models for sea turtles must be developed to determine what level of mortality can be sustained while balancing continued turtle population growth and fishing opportunity. Implementation of management targets should involve federal and state managers partnering with specific fisheries to develop bycatch reduction plans that are proportional to their impact on turtles.
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Identifying patterns in foraging-area origins in breeding aggregations of migratory species: Loggerhead turtles in the Northwest Atlantic. PLoS One 2020; 15:e0231325. [PMID: 32282844 PMCID: PMC7153900 DOI: 10.1371/journal.pone.0231325] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 03/20/2020] [Indexed: 11/20/2022] Open
Abstract
Population assessments conducted at reproductive sites of migratory species necessitate understanding the foraging-area origins of breeding individuals. Without this information, efforts to contextualize changes in breeding populations and develop effective management strategies are compromised. We used stable isotope analysis of tissue samples collected from loggerhead sea turtles (Caretta caretta) nesting at seven sites in the Northern Recovery Unit (NRU) of the eastern United States (North Carolina, South Carolina and Georgia) to assign females to three separate foraging areas in the Northwest Atlantic Ocean (NWA). We found that the majority of the females at NRU nesting sites (84.4%) use more northern foraging areas in the Mid-Atlantic Bight, while fewer females use more proximate foraging areas in the South Atlantic Bight (13.4%) and more southerly foraging areas in the Subtropical Northwest Atlantic (2.2%). We did not find significant latitudinal or temporal trends in the proportions of NRU females originating from different foraging areas. Combining these findings with previous data from stable isotope and satellite tracking studies across NWA nesting sites showed that variation in the proportion of adult loggerheads originating from different foraging areas is primarily related differences between recovery units: individuals in the NRU primarily use the Mid-Atlantic Bight foraging area, while individuals from the three Florida recovery units primarily use the Subtropical Northwest Atlantic and Eastern Gulf of Mexico foraging areas. Because each foraging area is associated with its own distinct ecological characteristics, environmental fluctuations and anthropogenic threats that affect the abundance and productivity of individuals at nesting sites, this information is critical for accurately evaluating population trends and developing effective region-specific management strategies.
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29
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Casale P, Ceriani SA. Sea turtle populations are overestimated worldwide from remigration intervals: correction for bias. ENDANGER SPECIES RES 2020. [DOI: 10.3354/esr01019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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