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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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Horne JB, Frey A, Gaos AR, Martin S, Dutton PH. Non-random mating within an Island rookery of Hawaiian hawksbill turtles: demographic discontinuity at a small coastline scale. ROYAL SOCIETY OPEN SCIENCE 2023; 10:221547. [PMID: 37206959 PMCID: PMC10189603 DOI: 10.1098/rsos.221547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 04/26/2023] [Indexed: 05/21/2023]
Abstract
Hawksbill sea turtles (Eretmochelys imbricata) from the Hawaiian archipelago form a small and genetically isolated population, consisting of only a few tens of individuals breeding annually. Most females nest on the island of Hawai'i, but little is known about the demographics of this rookery. This study used genetic relatedness, inferred from 135 microhaplotype markers, to determine breeding sex-ratios, estimate female nesting frequency and assess relationships between individuals nesting on different beaches. Samples were collected during the 2017 nesting season and final data included 13 nesting females and 1002 unhatched embryos, salvaged from 41 nests, of which 13 had no observed mother. Results show that most females used a single nesting beach laying 1-5 nests each. From female and offspring alleles, the paternal genotypes of 12 breeding males were reconstructed and many showed high relatedness to their mates. Pairwise relatedness of offspring revealed one instance of polygyny but otherwise suggested a 1 : 1 breeding-sex ratio. Relatedness analysis and spatial-autocorrelation of genotypes indicate that turtles from different nesting areas do not regularly interbreed, suggesting that strong natal homing tendencies in both sexes result in non-random mating across the study area. Complexes of nearby nesting beaches also showed unique patterns of inbreeding across loci, further indicating that Hawaiian hawksbill turtles have demographically discontinuous nesting populations separated by only tens of km.
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Affiliation(s)
- John B. Horne
- Southwest Fisheries Science Center, NOAA-Fisheries, La Jolla, CA, USA
| | - Amy Frey
- Southwest Fisheries Science Center, NOAA-Fisheries, La Jolla, CA, USA
| | - Alexander R. Gaos
- Pacific Islands Fisheries Science Center, NOAA-Fisheries, Honolulu, HI, USA
| | - Summer Martin
- Pacific Islands Fisheries Science Center, NOAA-Fisheries, Honolulu, HI, USA
| | - Peter H. Dutton
- Southwest Fisheries Science Center, NOAA-Fisheries, La Jolla, CA, USA
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Global phylogeography of ridley sea turtles (Lepidochelys spp.): evolution, demography, connectivity, and conservation. CONSERV GENET 2022; 23:995-1010. [PMID: 36397975 PMCID: PMC9659502 DOI: 10.1007/s10592-022-01465-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Accepted: 07/15/2022] [Indexed: 11/29/2022]
Abstract
Globally distributed marine taxa are well suited for investigations of biogeographic impacts on genetic diversity, connectivity, and population demography. The sea turtle genus Lepidochelys includes the wide-ranging and abundant olive ridley (L. olivacea), and the geographically restricted and ‘Critically Endangered’ Kemp’s ridley (L. kempii). To investigate their historical biogeography, we analyzed a large dataset of mitochondrial DNA (mtDNA) sequences from olive (n = 943) and Kemp’s (n = 287) ridleys, and genotyped 15 nuclear microsatellite loci in a global sample of olive ridleys (n = 285). We found that the ridley species split ~ 7.5 million years ago, before the Panama Isthmus closure. The most ancient mitochondrial olive ridley lineage, located in the Indian Ocean, was dated to ~ 2.2 Mya. Both mitochondrial and nuclear markers revealed significant structure for olive ridleys between Atlantic (ATL), East Pacific (EP), and Indo-West Pacific (IWP) areas. However, the divergence of mtDNA clades was very recent (< 1 Mya) with low within- clade diversity, supporting a recurrent extinction-recolonization model for these ocean regions. All data showed that ATL and IWP groups were more closely related than those in the EP, with mtDNA data supporting recent recolonization of the ATL from the IWP. Individual olive ridley dispersal between the ATL, EP, and IN/IWP could be interpreted as more male- than female-biased, and genetic diversity was lowest in the Atlantic Ocean. All populations showed signs of recent expansion, and estimated time frames were concordant with their recent colonization history. Investigating species abundance and distribution changes over time is central to evolutionary biology, and this study provides a historical biogeographic context for marine vertebrate conservation and management.
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Page-Karjian A, Whitmore L, Stacy BA, Perrault JR, Farrell JA, Shaver DJ, Walker JS, Frandsen HR, Rantonen E, Harms CA, Norton TM, Innis C, Yetsko K, Duffy DJ. Fibropapillomatosis and Chelonid Alphaherpesvirus 5 Infection in Kemp's Ridley Sea Turtles ( Lepidochelys kempii). Animals (Basel) 2021; 11:ani11113076. [PMID: 34827808 PMCID: PMC8614476 DOI: 10.3390/ani11113076] [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: 08/20/2021] [Revised: 09/29/2021] [Accepted: 10/04/2021] [Indexed: 12/04/2022] Open
Abstract
Simple Summary The Kemp’s ridley sea turtle is an endangered species that is susceptible to a tumor disease called fibropapillomatosis (FP) and its associated virus, chelonid alphaherpesvirus 5 (ChHV5). The goal of our study was to describe FP in Kemp’s ridley turtles, including estimated disease prevalence and pathologyg, and case demographics and outcomes, to better understand the risk posed by FP to Kemp’s ridley population recovery. During 2006–2020, we identified 22 cases of Kemp’s ridley turtles with FP, including 12 adult turtles, a reproductively valuable age class. Molecular diagnostics were used to identify ChHV5 DNA in blood (7.8%) and tumor (91.7%) samples collected from free-ranging Kemp’s ridley turtles. Genomic sequencing was conducted to identify ChHV5 variants in tumor samples collected from Kemp’s ridley turtles with FP. Along with case data, phylogenetic analysis of resultant sequences suggests increasing, spatiotemporal spread of ChHV5 infections and FP among Kemp’s ridley turtles in coastal areas, including the Gulf of Mexico and the southwestern Atlantic Ocean, where they share habitat with green sea turtles (in which FP is enzootic). This is concerning because FP has an uncertain pathogenesis, is potentially related to anthropogenic environmental degradation, and can cause suffering and/or death in severely afflicted turtles. Abstract Fibropapillomatosis (FP), a debilitating, infectious neoplastic disease, is rarely reported in endangered Kemp’s ridley sea turtles (Lepidochelys kempii). With this study, we describe FP and the associated chelonid alphaherpesvirus 5 (ChHV5) in Kemp’s ridley turtles encountered in the United States during 2006–2020. Analysis of 22 case reports of Kemp’s ridley turtles with FP revealed that while the disease was mild in most cases, 54.5% were adult turtles, a reproductively valuable age class whose survival is a priority for population recovery. Of 51 blood samples from tumor-free turtles and 12 tumor samples from turtles with FP, 7.8% and 91.7%, respectively, tested positive for ChHV5 DNA via quantitative polymerase chain reaction (qPCR). Viral genome shotgun sequencing and phylogenetic analysis of six tumor samples show that ChHV5 sequences in Kemp’s ridley turtles encountered in the Gulf of Mexico and northwestern Atlantic cluster with ChHV5 sequences identified in green (Chelonia mydas) and loggerhead (Caretta caretta) sea turtles from Hawaii, the southwestern Atlantic Ocean, and the Caribbean. Results suggest an interspecific, spatiotemporal spread of FP among Kemp’s ridley turtles in regions where the disease is enzootic. Although FP is currently uncommon in this species, it remains a health concern due to its uncertain pathogenesis and potential relationship with habitat degradation.
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Affiliation(s)
- Annie Page-Karjian
- Harbor Branch Oceanographic Institute, Florida Atlantic University, Fort Pierce, FL 34946, USA;
- Correspondence:
| | - Liam Whitmore
- Whitney Laboratory for Marine Bioscience and Sea Turtle Hospital, University of Florida, St. Augustine, FL 32080, USA; (L.W.); (J.A.F.); (K.Y.); (D.J.D.)
- Department of Biological Sciences, University of Limerick, V94 T9PX Co. Limerick, Ireland
| | - Brian A. Stacy
- National Oceanic & Atmospheric Administration, National Marine Fisheries Service, Gainesville, FL 32611, USA;
| | | | - Jessica A. Farrell
- Whitney Laboratory for Marine Bioscience and Sea Turtle Hospital, University of Florida, St. Augustine, FL 32080, USA; (L.W.); (J.A.F.); (K.Y.); (D.J.D.)
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Donna J. Shaver
- Division of Sea Turtle Science and Recovery, Padre Island National Seashore, Corpus Christi, TX 78480, USA; (D.J.S.); (J.S.W.); (H.R.F.)
| | - J. Shelby Walker
- Division of Sea Turtle Science and Recovery, Padre Island National Seashore, Corpus Christi, TX 78480, USA; (D.J.S.); (J.S.W.); (H.R.F.)
| | - Hilary R. Frandsen
- Division of Sea Turtle Science and Recovery, Padre Island National Seashore, Corpus Christi, TX 78480, USA; (D.J.S.); (J.S.W.); (H.R.F.)
| | - Elina Rantonen
- Harbor Branch Oceanographic Institute, Florida Atlantic University, Fort Pierce, FL 34946, USA;
| | - Craig A. Harms
- Center for Marine Science & Technology, North Carolina State University, Morehead City, NC 28557, USA;
| | | | | | - Kelsey Yetsko
- Whitney Laboratory for Marine Bioscience and Sea Turtle Hospital, University of Florida, St. Augustine, FL 32080, USA; (L.W.); (J.A.F.); (K.Y.); (D.J.D.)
| | - David J. Duffy
- Whitney Laboratory for Marine Bioscience and Sea Turtle Hospital, University of Florida, St. Augustine, FL 32080, USA; (L.W.); (J.A.F.); (K.Y.); (D.J.D.)
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
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Shaver DJ, Gredzens C, Walker JS, Godard-Codding CAJ, Yacabucci JE, Frey A, Dutton PH, Schmitt CJ. Embryo deformities and nesting trends in Kemp’s ridley sea turtles Lepidochelys kempii before and after the Deepwater Horizon oil spill. ENDANGER SPECIES RES 2021. [DOI: 10.3354/esr01107] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Kemp’s ridley sea turtles Lepidochelys kempii were disproportionately affected by the Deepwater Horizon (DWH) oil spill, which began on 20 April 2010. Embryo deformities were documented in inviable L. kempii eggs before (2008-2010) and after (2011-2013) the DWH spill in 2 Texas (USA) nesting areas (Upper Texas Coast and Padre Island National Seashore). Additional nesting trends, including clutch size and hatching success, were also investigated. Total and late-stage embryo deformity prevalence were 1.5 times greater after 2010 than before, but low in all nesting seasons (mean ± SD: 0.7 ± 8.5% total; 0.6 ± 8.0% late-stage) and did not differ between locations. Craniofacial and carapace deformities were the most frequently observed deformity types. Documented nests in both areas declined in 2010 relative to previous years, ending an exponential increase observed beginning in 1995. Clutch size remained consistent before and after the spill. Hatching success averaged 87.0 ± 33.3% in all years, but no effects from DWH were determined. Collectively, these data represent useful benchmarks against which to judge impacts of future crude oil spills and other catastrophic events.
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Affiliation(s)
- DJ Shaver
- National Park Service, Padre Island National Seashore, Corpus Christi, TX 78480, USA
| | - C Gredzens
- National Park Service, Padre Island National Seashore, Corpus Christi, TX 78480, USA
| | - JS Walker
- National Park Service, Padre Island National Seashore, Corpus Christi, TX 78480, USA
| | - CAJ Godard-Codding
- The Institute of Environmental and Human Health, Texas Tech University, Lubbock, TX 79409, USA
| | - JE Yacabucci
- The Institute of Environmental and Human Health, Texas Tech University, Lubbock, TX 79409, USA
| | - A Frey
- NOAA Fisheries, Southwest Fisheries Science Center, La Jolla, CA 92037, USA
| | - PH Dutton
- NOAA Fisheries, Southwest Fisheries Science Center, La Jolla, CA 92037, USA
| | - CJ Schmitt
- US Geological Survey, Columbia Environmental Research Center, Columbia, MO 65201, USA
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Banerjee SM, Frey A, Kurle CM, Perrault JR, Stewart KR. Morphological variation in leatherback (Dermochelys coriacea) hatchlings at Sandy Point National Wildlife Refuge, US Virgin Islands. ENDANGER SPECIES RES 2020. [DOI: 10.3354/esr01030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Understanding species’ mating systems provides important information about their ecology, life history, and behavior. Direct observations of mating behaviors can be challenging, but molecular techniques can reveal information about mating systems and paternal identity in difficult-to-observe species such as sea turtles. Genetic markers can be used to assess the paternity of a clutch and to assign hatchlings to a father. Leatherback turtles Dermochelys coriacea sometimes mate with multiple individuals, resulting in clutches with mixed paternity; however, the effects of multiple paternity on hatchling quality are unclear. Leatherback hatchlings at Sandy Point National Wildlife Refuge, St. Croix, US Virgin Islands, exhibit visible variation in individual body size, sometimes within the same clutch. We collected morphometrics and tissue samples from hatchlings across multiple nesting seasons (2009, 2012, 2013, 2015, and 2016) and found that hatchlings exhibited small but statistically significant differences in morphometrics between years. We used maternal and hatchling microsatellite genotypes to reconstruct paternal genotypes, assigning fathers to each hatchling. We found multiple paternity in 5 of 17 clutches analyzed and compared differences in morphometrics between full-siblings with differences between half-siblings. We found no significant differences between morphometrics of hatchlings from the same mother but different fathers. We compared within-clutch variances in morphometrics for clutches with and without multiple paternity and found no significant difference in morphological variation between them. Therefore, we could not attribute differences in hatchling size within a clutch to paternal contribution. Understanding other factors affecting hatchling morphology, and other possible fitness metrics, may reveal insights into the benefits, or lack thereof, of polyandry in sea turtles.
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Affiliation(s)
- SM Banerjee
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92037, USA, ORCID: 0000-0003-1210-2162
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - A Frey
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, La Jolla, CA 92037, USA
| | - CM Kurle
- Division of Biological Sciences, Ecology, Behavior, and Evolution Section, University of California, San Diego, La Jolla, CA 92093, USA, ORCID: 0000-0003-1121-9924
| | - JR Perrault
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA
- Loggerhead Marinelife Center, Juno Beach, FL 33408, USA, ORCID: 0000-0002-5046-6701
| | - KR Stewart
- The Ocean Foundation, Washington, DC 20036, USA, ORCID: 0000-0002-8673-5192
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Clendenin HR, Adams JR, Ausband DE, Hayden JA, Hohenlohe PA, Waits LP. Combining Harvest and Genetics to Estimate Reproduction in Wolves. J Wildl Manage 2020. [DOI: 10.1002/jwmg.21820] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Heather R. Clendenin
- Department of Biological Sciences, Institute for Bioinformatics and Evolutionary StudiesUniversity of Idaho 875 Perimeter Drive MS3051 Moscow ID 83844‐3051 USA
| | - Jennifer R. Adams
- Department of Fish and Wildlife Sciences, Laboratory for Ecological, Evolutionary and Conservation GeneticsUniversity of Idaho 875 Perimeter Drive MS1136 Moscow ID 83844‐1136 USA
| | | | - James A. Hayden
- Idaho Department of Fish and Game, P.O. Box 25Boise ID 83814 USA
| | - Paul A. Hohenlohe
- Department of Biological Sciences, Institute for Bioinformatics and Evolutionary StudiesUniversity of Idaho 875 Perimeter Drive MS3051 Moscow ID 83844‐3051 USA
| | - Lisette P. Waits
- Department of Fish and Wildlife SciencesUniversity of Idaho 875 Perimeter Drive MS1136 Moscow ID 83844‐1136 USA
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Multiple Paternity in a Reintroduced Rookery of Kemp's Ridley Sea Turtles on South Padre Island, Texas. J HERPETOL 2020. [DOI: 10.1670/18-003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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9
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Frandsen HR, Figueroa DF, George JA. Mitochondrial genomes and genetic structure of the Kemp's ridley sea turtle ( Lepidochelys kempii). Ecol Evol 2020; 10:249-262. [PMID: 31988726 PMCID: PMC6972797 DOI: 10.1002/ece3.5891] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 10/23/2019] [Accepted: 11/13/2019] [Indexed: 12/03/2022] Open
Abstract
The Kemp's ridley (Lepidochelys kempii) is the world's most endangered sea turtle species and is primarily distributed in the Gulf of Mexico. In the United States, South Padre Island, Texas serves as a key nesting ground for the species. Genetic studies of the Kemp's ridley have been used to aid in conservation and management practices, with the mitochondrial control region as the most commonly used marker due to its perceived hypervariability and ease of sequencing. However, with the advent of next generation sequencing technology, targeting complete mitochondrial genomes is now feasible. Here, we describe a more complete mitochondrial genome for the Kemp's ridley than has been previously published in literature and demonstrate a cost-effective and efficient method for obtaining complete mitochondrial genomes from sea turtles. We compare the genetic diversity and taxonomic resolution obtained from whole mitochondrial genomes to that obtained from the mitochondrial control region alone. We compare current genetic diversity with previous records. Furthermore, we evaluate the genetic structure between the breeding stock in South Padre Island and that of deceased Kemp's ridleys recovered on the Northern coast of the Gulf of Mexico after the 2010 BP Deepwater Horizon oil spill, and of Kemp's ridleys stranded on the East Coast of the United States. Our results show that complete mitochondrial genomes provide greater resolution than the control region alone. They also show that the genetic diversity of the Kemp's ridley has remained stable, despite large population declines, and that the genetic makeup of deceased turtles stranded after the Deepwater Horizon oil spill is indistinguishable from the breeding stock in South Padre Island, Texas. OPEN DATA BADGE This article has earned an Open Data Badge for making publicly available the digitally-shareable data necessary to reproduce the reported results. The data is available at https://www.ncbi.nlm.nih.gov/genbank/.
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Sampling strategies for species with high breeding-site fidelity: A case study in burrow-nesting seabirds. PLoS One 2019; 14:e0221625. [PMID: 31454375 PMCID: PMC6711508 DOI: 10.1371/journal.pone.0221625] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 08/12/2019] [Indexed: 11/19/2022] Open
Abstract
Sampling approaches used to census and monitor populations of flora and fauna are diverse, ranging from simple random sampling to complex hierarchal stratified designs. Usually the approach taken is determined by the spatial and temporal distribution of the study population, along with other characteristics of the focal species. Long-term monitoring programs used to assess seabird population trends are facilitated by their high site fidelity, but are often hampered by large and difficult to access colonies, with highly variable densities that require intensive survey. We aimed to determine the sampling effort required to (a) estimate population size with a high degree of confidence, and (b) detect different scenarios of population change in a regionally important species in the Atlantic, the Manx shearwater (Puffinus puffinus). Analyses were carried out using data collected from tape-playback surveys on four islands in the North Atlantic. To explore how sampling effort influenced confidence around abundance estimates, we used the heuristic approach of imagining the areas sampled represented the total population, and bootstrapped varying proportions of subsamples. This revealed that abundance estimates vary dramatically when less than half of all plots (n dependent on the size of the site) is randomly subsampled, leading to an unacceptable lack of confidence in population estimates. Confidence is substantially improved using a multi-stage stratified approach based on previous information on distribution in the colonies. In reality, this could lead to reducing the number of plots required by up to 80%. Furthermore, power analyses suggested that random selection of monitoring plots using a matched pairs approach generates little power to detect overall population changes of 10%, and density-dependent changes as large as 50%, because variation in density between plots is so high. Current monitoring programs have a high probability of failing to detect population-level changes due to inappropriate sampling efforts. Focusing sampling in areas of high density with low plot to plot variance dramatically increases the power to detect year to year population change, albeit at the risk of not detecting increases in low density areas, which may be an unavoidable strategy when resources are limited. We discuss how challenging populations with similar features to seabirds might be censused and monitored most effectively.
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Kocmoud AR, Wang HH, Grant WE, Gallaway BJ. Population dynamics of the endangered Kemp’s ridley sea turtle following the 2010 oil spill in the Gulf of Mexico: Simulation of potential cause-effect relationships. Ecol Modell 2019. [DOI: 10.1016/j.ecolmodel.2018.11.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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12
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Shamblin BM, Godfrey MH, Pate SM, Thompson WP, Sutton H, Altman J, Fair K, McClary J, Wilson AM, Milligan B, Stetzar EJ, Nairn CJ. Green Turtles Nesting at Their Northern Range Limit in the United States Represent a Distinct Subpopulation. CHELONIAN CONSERVATION AND BIOLOGY 2018. [DOI: 10.2744/ccb-1332.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Brian M. Shamblin
- Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia 3
| | - Matthew H. Godfrey
- North Carolina Wildlife Resources Commission, Beaufort, North Carolina 28516 USA [matt.godfrey@ncwil
| | - S. Michelle Pate
- South Carolina Department of Natural Resources, Charleston, South Carolina 29412 USA [
| | - William P. Thompson
- Cape Hatteras National Seashore, National Park Service, Buxton, North Carolina 27920 USA [william_p_
| | - Hope Sutton
- North Carolina National Estuarine Research Reserve, University of North Carolina Wilmington Center f
| | - Jon Altman
- Cape Lookout National Seashore, National Park Service, Harkers Island, North Carolina 28531 USA [jon
| | - Kristina Fair
- Pea Island National Wildlife Refuge, US Fish and Wildlife Service, Manteo, North Carolina 27954 USA
| | - Jeffrey McClary
- South Carolina United Turtle Enthusiasts (S.C.U.T.E.), Pawleys Island, South Carolina 29585 USA [scu
| | - Ann M. Wilson
- Myrtle Beach State Park, Myrtle Beach, South Carolina 29575 USA []
| | - Brooke Milligan
- Bald Head Island Conservancy, Bald Head Island, North Carolina 28461 USA []
| | - Edna J. Stetzar
- Delaware Department of Natural Resources and Environmental Control, Dover, Delaware 19901 USA [edna
| | - Campbell J. Nairn
- Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia 3
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Esteban N, Mortimer JA, Hays GC. How numbers of nesting sea turtles can be overestimated by nearly a factor of two. Proc Biol Sci 2018; 284:rspb.2016.2581. [PMID: 28202810 DOI: 10.1098/rspb.2016.2581] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 01/23/2017] [Indexed: 11/12/2022] Open
Abstract
Estimating the absolute number of individuals in populations and their fecundity is central to understanding the ecosystem role of species and their population dynamics as well as allowing informed conservation management for endangered species. Estimates of abundance and fecundity are often difficult to obtain for rare or cryptic species. Yet, in addition, here we show for a charismatic group, sea turtles, that are neither cryptic nor rare and whose nesting is easy to observe, that the traditional approach of direct observations of nesting has likely led to a gross overestimation of the number of individuals in populations and underestimation of their fecundity. We use high-resolution GPS satellite tags to track female green turtles throughout their nesting season in the Chagos Archipelago (Indian Ocean) and assess when and where they nested. For individual turtles, nest locations were often spread over several tens of kilometres of coastline. Assessed by satellite observations, a mean of 6.0 clutches (range 2-9, s.d. = 2.2) was laid by individuals, about twice as many as previously assumed, a finding also reported in other species and ocean basins. Taken together, these findings suggest that the actual number of nesting turtles may be almost 50% less than previously assumed.
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Affiliation(s)
- Nicole Esteban
- Department of Biosciences, Swansea University, Swansea SA2 8PP, Wales, UK
| | - Jeanne A Mortimer
- Turtle Action Group of Seychelles, PO Box 1443, Victoria, Mahé, Seychelles.,Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Graeme C Hays
- Deakin University, Geelong, Australia, School of Life and Environmental Sciences, Centre for Integrative Ecology, Warrnambool, VIC 3280, Australia
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Warden ML, Haas HL, Richards PM, Rose KA, Hatch JM. Monitoring trends in sea turtle populations: walk or fly? ENDANGER SPECIES RES 2017. [DOI: 10.3354/esr00855] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Shaver DJ, Hart KM, Fujisaki I, Bucklin D, Iverson AR, Rubio C, Backof TF, Burchfield PM, de Jesus Gonzales Diaz Miron R, Dutton PH, Frey A, Peña J, Gomez Gamez D, Martinez HJ, Ortiz J. Inter-nesting movements and habitat-use of adult female Kemp's ridley turtles in the Gulf of Mexico. PLoS One 2017; 12:e0174248. [PMID: 28319178 PMCID: PMC5358874 DOI: 10.1371/journal.pone.0174248] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 03/06/2017] [Indexed: 12/04/2022] Open
Abstract
Species vulnerability is increased when individuals congregate in restricted areas for breeding; yet, breeding habitats are not well defined for many marine species. Identification and quantification of these breeding habitats are essential to effective conservation. Satellite telemetry and switching state-space modeling (SSM) were used to define inter-nesting habitat of endangered Kemp’s ridley turtles (Lepidochelys kempii) in the Gulf of Mexico. Turtles were outfitted with satellite transmitters after nesting at Padre Island National Seashore, Texas, USA, from 1998 through 2013 (n = 60); Rancho Nuevo, Tamaulipas, Mexico, during 2010 and 2011 (n = 11); and Tecolutla, Veracruz, Mexico, during 2012 and 2013 (n = 11). These sites span the range of nearly all nesting by this species. Inter-nesting habitat lies in a narrow band of nearshore western Gulf of Mexico waters in the USA and Mexico, with mean water depth of 14 to 19 m within a mean distance to shore of 6 to 11 km as estimated by 50% kernel density estimate, α-Hull, and minimum convex polygon methodologies. Turtles tracked during the inter-nesting period moved, on average, 17.5 km/day and a mean total distance of 398 km. Mean home ranges occupied were 725 to 2948 km2. Our results indicate that these nearshore western Gulf waters represent critical inter-nesting habitat for this species, where threats such as shrimp trawling and oil and gas platforms also occur. Up to half of all adult female Kemp’s ridleys occupy this habitat for weeks to months during each nesting season. Because inter-nesting habitat for this species is concentrated in nearshore waters of the western Gulf of Mexico in both Mexico and the USA, international collaboration is needed to protect this essential habitat and the turtles occurring within it.
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Affiliation(s)
- Donna J. Shaver
- National Park Service, Padre Island National Seashore, Corpus Christi, Texas, United States of America
- * E-mail:
| | - Kristen M. Hart
- U.S. Geological Survey, Wetland and Aquatic Research Center, Davie, Florida, United States of America
| | - Ikuko Fujisaki
- University of Florida, Ft. Lauderdale Research and Education Center, Davie, Florida, United States of America
| | - David Bucklin
- University of Florida, Ft. Lauderdale Research and Education Center, Davie, Florida, United States of America
| | - Autumn R. Iverson
- Cherokee Nation Technologies, contracted to U.S. Geological Survey, Wetland and Aquatic Research Center, Davie, Florida, United States of America
| | - Cynthia Rubio
- National Park Service, Padre Island National Seashore, Corpus Christi, Texas, United States of America
| | - Thomas F. Backof
- National Park Service, Padre Island National Seashore, Corpus Christi, Texas, United States of America
| | | | | | - Peter H. Dutton
- National Oceanographic and Atmospheric Administration, National Marine Fisheries Service, Southwest Fisheries Science Center, La Jolla, California, United States of America
| | - Amy Frey
- National Oceanographic and Atmospheric Administration, National Marine Fisheries Service, Southwest Fisheries Science Center, La Jolla, California, United States of America
| | - Jaime Peña
- Gladys Porter Zoo, Brownsville, Texas, United States of America
| | | | | | - Jaime Ortiz
- Gladys Porter Zoo, Brownsville, Texas, United States of America
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Rees AF, Alfaro-Shigueto J, Barata PCR, Bjorndal KA, Bolten AB, Bourjea J, Broderick AC, Campbell LM, Cardona L, Carreras C, Casale P, Ceriani SA, Dutton PH, Eguchi T, Formia A, Fuentes MMPB, Fuller WJ, Girondot M, Godfrey MH, Hamann M, Hart KM, Hays GC, Hochscheid S, Kaska Y, Jensen MP, Mangel JC, Mortimer JA, Naro-Maciel E, Ng CKY, Nichols WJ, Phillott AD, Reina RD, Revuelta O, Schofield G, Seminoff JA, Shanker K, Tomás J, van de Merwe JP, Van Houtan KS, Vander Zanden HB, Wallace BP, Wedemeyer-Strombel KR, Work TM, Godley BJ. Are we working towards global research priorities for management and conservation of sea turtles? ENDANGER SPECIES RES 2016. [DOI: 10.3354/esr00801] [Citation(s) in RCA: 175] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Shaver DJ, Lamont MM, Maxwell S, Walker JS, Dillingham T. Head-Started Kemp's Ridley Turtle (Lepidochelys kempii) Nest Recorded in Florida: Possible Implications. CHELONIAN CONSERVATION AND BIOLOGY 2016. [DOI: 10.2744/ccb-1192.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Donna J. Shaver
- National Park Service, Padre Island National Seashore, PO Box 181300, Corpus Christi, Texas 78480-1300 USA [ ; ]
| | - Margaret M. Lamont
- US Geological Survey, Wetland and Aquatic Research Center, Gainesville, Florida 32653 USA [ ]
| | - Sharon Maxwell
- South Walton Turtle Watch Group, 74 Birch Street, Freeport, Florida 32439 USA [ ]
| | - Jennifer Shelby Walker
- National Park Service, Padre Island National Seashore, PO Box 181300, Corpus Christi, Texas 78480-1300 USA [ ; ]
| | - Ted Dillingham
- 130 Hickory Hill Road SE, Decatur, Alabama 35603 USA [ ]
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