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Sanchez CL, Casale P, Bunbury N, A'Bear L, Banane V, Benstrong F, Bielsa M, Jones CW, Koester A, Murasko S, van Rooyen MC, Fleischer-Dogley F, Ceriani SA. Fine-scale foraging ecology and habitat use of sympatric green and hawksbill turtles in the Western Indian ocean. MARINE ENVIRONMENTAL RESEARCH 2024; 198:106529. [PMID: 38688109 DOI: 10.1016/j.marenvres.2024.106529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 04/01/2024] [Accepted: 04/26/2024] [Indexed: 05/02/2024]
Abstract
Using stable isotope analysis of carbon and nitrogen of turtle tissues and putative prey items, we investigated the diet of immature green turtles and hawksbill turtles foraging in the lagoon of Aldabra Atoll, a relatively undisturbed atoll in the southern Seychelles. Aldabra offers a unique environment for understanding sea turtle ecology. Green turtles mostly consumed seagrass and brown algae while hawksbill turtles mainly consumed mangroves and invertebrates. Green turtles showed a dietary shift with size (a proxy for age). There was minimal niche overlap between species and evidence of small-scale foraging site fidelity with turtle tissue reflecting site-specific prey. This highlights the ecological importance of seagrass and mangrove habitats and suggests that turtles play a role in controlling algal biomass at Aldabra. This study is the first to closely examine the foraging ecology of these sympatric turtle species in the Western Indian Ocean, a globally important region for both species.
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Affiliation(s)
- Cheryl L Sanchez
- Department of Biology, University of Pisa, Via A. Volta 6, 56126 Pisa, Italy; Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, Saint Petersburg, FL, USA; Seychelles Islands Foundation, Mahé, P.O. Box 853, Victoria, Seychelles
| | - Paolo Casale
- Department of Biology, University of Pisa, Via A. Volta 6, 56126 Pisa, Italy.
| | - Nancy Bunbury
- Seychelles Islands Foundation, Mahé, P.O. Box 853, Victoria, Seychelles; Centre for Ecology and Conservation, University of Exeter, Cornwall Campus, Penryn TR10 9FE, UK
| | - Luke A'Bear
- Seychelles Islands Foundation, Mahé, P.O. Box 853, Victoria, Seychelles
| | - Veronique Banane
- Seychelles Islands Foundation, Mahé, P.O. Box 853, Victoria, Seychelles
| | - Frances Benstrong
- Seychelles Islands Foundation, Mahé, P.O. Box 853, Victoria, Seychelles
| | - Maria Bielsa
- Seychelles Islands Foundation, Mahé, P.O. Box 853, Victoria, Seychelles
| | | | - Anna Koester
- Seychelles Islands Foundation, Mahé, P.O. Box 853, Victoria, Seychelles
| | - Susan Murasko
- Department of Biology, University of Pisa, Via A. Volta 6, 56126 Pisa, Italy
| | | | | | - Simona A Ceriani
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, Saint Petersburg, FL, USA; Department of Biology, University of Central Florida, Orlando, FL, USA
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Turner Tomaszewicz CN, Liles MJ, Avens L, Seminoff JA. Tracking movements and growth of post-hatchling to adult hawksbill sea turtles using skeleto+iso. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.983260] [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
In the eastern Pacific Ocean, hawksbill sea turtles (Eretmochelys imbricata) are adapted to use coastal habitats and ecosystems uncharacteristic of most other sea turtles. Once considered extirpated from this region, hawksbills had sought refuge in estuaries, nesting on muddy banks among the tangles of mangrove roots. This population is at high risk of bycatch during fishing efforts in the estuaries (blast fishing) and adjacent coastal rocky reefs (gillnets), and is further impacted by habitat degradation from coastal development and climate change. The conservation and population recovery of hawksbills in this region is highly dependent on management actions (e.g., nest relocation, habitat protection, bycatch mitigation), and a better understanding of how hawksbills use and move between distinct habitats will help prioritize conservation efforts. To identify multi-year habitat use and movement patterns, we used stable carbon (δ13C) and nitrogen (δ15N) isotope analysis of skin and bone growth layers to recreate movements between two isotopically distinct habitats, a nearshore rocky reef and a mangrove estuary, the latter distinguishable by low δ13C and δ15N values characteristic of a mangrove-based foodweb. We applied skeletochronology with sequential δ13C and δ15N analysis of annual growth layers, “skeleto+iso,” to a dataset of 70 hawksbill humeri collected from coastal El Salvador. The results revealed at least two unique habitat-use patterns. All turtles, regardless of stranding location, spent time outside of the mangrove estuaries during their early juvenile years (< 35 cm curved carapace length, CCL, age 0–5), showing that an oceanic juvenile stage is likely for this population. Juveniles ca. > 35 cm then began to recruit to nearshore areas, but showed divergent habitat-use as some of turtles occupied the coastal rocky reefs, while others settled into the mangrove estuaries. For turtles recruiting to the estuaries, settlement age and size ranged from 3 to 13 years and 35–65 cm CCL. For the adult turtles, age-at-sexual-maturity ranged from 16 to 26 years, and the maximum reproductive longevity observed was 33 years. The skeleto+iso also showed that adult hawksbills have long-term habitat fidelity, and the results demonstrate the importance of both mangrove estuary and nearshore rocky reefs to the conservation of hawksbills in the eastern Pacific.
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Arantes LS, Vargas SM, Santos FR. Global phylogeography of the critically endangered hawksbill turtle (Eretmochelys imbricata). Genet Mol Biol 2020; 43:e20190264. [PMID: 32555943 PMCID: PMC7288670 DOI: 10.1590/1678-4685-gmb-2019-0264] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 03/11/2020] [Indexed: 11/22/2022] Open
Abstract
The hawksbill turtle is a broadly distributed, highly migratory and critically endangered sea turtle species. The paucity of studies restricts the comprehension of its behavior and life history. In this work, we performed a global phylogeographic analysis using a compilation of previously published mitochondrial haplotype data to understand the dynamics and diversity of hawksbill populations worldwide. Our results revealed a complex demographic pattern associated to hawksbill phylogeography since the Pliocene. Isolation by distance is not enough to explain distinct demographic units of hawksbill turtles, which are also influenced by other factors as oceanic currents, coral reef distribution and nesting timing. The foraging aggregations are typically mixed stocks of individuals originating from multiple nesting areas, but there is also a trend of foragers coming from nearby natal beaches. Phylogenetic analysis indicates two highly divergent major lineages split between Atlantic and Indo-Pacific rookeries, but there is also a more recent Atlantic Ocean colonization from the Indo-Pacific Ocean. Long-distance dispersal events are likely responsible for homogenization between distant populations within oceans. Our findings provided new insights about population connectivity, identified gaps that should be prioritized in future research and highlighted the need for international efforts aiming at hawksbill's conservation.
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Affiliation(s)
- Larissa S Arantes
- Universidade Federal de Minas Gerais (UFMG), Instituto de Ciências Biológicas, Departamento de Genética, Ecologia e Evolução, Belo Horizonte, MG, Brazil
| | - Sarah M Vargas
- Universidade Federal do Espírito Santo (UFES), Instituto de Ciências Humanas e Naturais, Departamento de Ciências Biológicas, Vitória, ES, Brazil
| | - Fabrício R Santos
- Universidade Federal de Minas Gerais (UFMG), Instituto de Ciências Biológicas, Departamento de Genética, Ecologia e Evolução, Belo Horizonte, MG, Brazil
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Gaos AR, Lewison RL, Jensen MP, Liles MJ, Henriquez A, Chavarria S, Pacheco CM, Valle M, Melero D, Gadea V, Altamirano E, Torres P, Vallejo F, Miranda C, LeMarie C, Lucero J, Oceguera K, Chácon D, Fonseca L, Abrego M, Seminoff JA, Flores EE, Llamas I, Donadi R, Peña B, Muñoz JP, Ruales DA, Chaves JA, Otterstrom S, Zavala A, Hart CE, Brittain R, Alfaro-Shigueto J, Mangel J, Yañez IL, Dutton PH. Natal foraging philopatry in eastern Pacific hawksbill turtles. ROYAL SOCIETY OPEN SCIENCE 2017; 4:170153. [PMID: 28878969 PMCID: PMC5579084 DOI: 10.1098/rsos.170153] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 07/26/2017] [Indexed: 06/07/2023]
Abstract
The complex processes involved with animal migration have long been a subject of biological interest, and broad-scale movement patterns of many marine turtle populations still remain unresolved. While it is widely accepted that once marine turtles reach sexual maturity they home to natal areas for nesting or reproduction, the role of philopatry to natal areas during other life stages has received less scrutiny, despite widespread evidence across the taxa. Here we report on genetic research that indicates that juvenile hawksbill turtles (Eretmochelys imbricata) in the eastern Pacific Ocean use foraging grounds in the region of their natal beaches, a pattern we term natal foraging philopatry. Our findings confirm that traditional views of natal homing solely for reproduction are incomplete and that many marine turtle species exhibit philopatry to natal areas to forage. Our results have important implications for life-history research and conservation of marine turtles and may extend to other wide-ranging marine vertebrates that demonstrate natal philopatry.
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Affiliation(s)
- Alexander R. Gaos
- Department of Biology, San Diego State University, San Diego, CA, USA
- Graduate Group in Ecology, University of California Davis, Davis, CA, USA
- Marine Mammal and Turtle Division, Ocean Associates Inc., under contract to the Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, La Jolla, CA, USA
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | | | - Michael P. Jensen
- Marine Mammal and Turtle Division, Ocean Associates Inc., under contract to the Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, La Jolla, CA, USA
| | - Michael J. Liles
- Department of Biology, University of Texas at El Paso, El Paso, TX, USA
- ProCosta, San Salvador, El Salvador
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Ana Henriquez
- ProCosta, San Salvador, El Salvador
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Sofia Chavarria
- ProCosta, San Salvador, El Salvador
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Carlos Mario Pacheco
- ProCosta, San Salvador, El Salvador
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Melissa Valle
- ProCosta, San Salvador, El Salvador
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - David Melero
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Velkiss Gadea
- Marine Turtles Department, Fauna & Flora International, Managua, Nicaragua
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Eduardo Altamirano
- Marine Turtles Department, Fauna & Flora International, Managua, Nicaragua
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Perla Torres
- Instituto de Ciencias del Mar y Limnología, Unidad Académica Mazatlán, Universidad Nacional de Mexico, Mazatlán, Mexico
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Felipe Vallejo
- Equilibrio Azul, Quito, Ecuador
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Cristina Miranda
- Equilibrio Azul, Quito, Ecuador
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Carolina LeMarie
- Equilibrio Azul, Quito, Ecuador
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Jesus Lucero
- Grupo Tortuguero de las Californias, A.C, La Paz, Mexico
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Karen Oceguera
- Grupo Tortuguero de las Californias, A.C, La Paz, Mexico
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Didiher Chácon
- Latin American Sea Turtles, Tibás, Costa Rica
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Luis Fonseca
- Latin American Sea Turtles, Tibás, Costa Rica
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Marino Abrego
- Conservación de Recursos Costeros y Marinos, Ministerio del Ambiente de Panamá, Panama City, Panama
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Jeffrey A. Seminoff
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, La Jolla, CA, USA
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Eric E. Flores
- Sistema Nacional de Investigación, Panama City, Panama
- Instituto de Investigaciones Científicas y Servicios de Alta Tecnología, Panama City, Panama
| | - Israel Llamas
- Campamento Tortuguero Mayto, A.C., Mayto, Mexico
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | | | - Bernardo Peña
- Conservación de Recursos Costeros y Marinos, Ministerio del Ambiente de Panamá, Panama City, Panama
| | - Juan Pablo Muñoz
- Marine Ecology Department, Universidad San Francisco de Quito/Galapagos Science Center, San Cristóbal, Galapagos Archipelago, Ecuador
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Daniela Alarcòn Ruales
- Marine Ecology Department, Universidad San Francisco de Quito/Galapagos Science Center, San Cristóbal, Galapagos Archipelago, Ecuador
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Jaime A. Chaves
- Marine Ecology Department, Universidad San Francisco de Quito/Galapagos Science Center, San Cristóbal, Galapagos Archipelago, Ecuador
| | - Sarah Otterstrom
- Paso Pacifico, Managua, Nicaragua
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Alan Zavala
- Unidad Sinaloa, Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional, Sinaloa, Mexico
- Instituto Politécnico Nacional, Sinaloa, Mexico
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Catherine E. Hart
- Red Tortuguera, A.C, Guayabitos, Mexico
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Rachel Brittain
- Akazul, La Barrona, Guatemala
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Joanna Alfaro-Shigueto
- Marine Turtle Research Group, School of Biosciences, University of Exeter, Penryn, UK
- Marine Biology Department, Universidad Cientifica del Sur, Lima, Peru
- ProDelphinus, Lima, Peru
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | - Jeffrey Mangel
- Marine Turtle Research Group, School of Biosciences, University of Exeter, Penryn, UK
- Eastern Pacific Hawksbill Initiative, San Diego, CA, USA
| | | | - Peter H. Dutton
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, La Jolla, CA, USA
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