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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] [MESH Headings] [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
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, Saint Petersburg, FL, USA
| | | | | | - Simona A Ceriani
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, Saint Petersburg, 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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Moncada F, Revuelta O, Nodarse G, Medina Y, Caderno A. Juvenile Hawksbill Turtles, Eretmochelys imbricata, in the Jardines de la Reina Archipelago, Cuba. CHELONIAN CONSERVATION AND BIOLOGY 2022. [DOI: 10.2744/ccb-1504.1] [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)
- Félix Moncada
- Centro de Investigaciones Pesqueras, 248 No. 0603, e/5a ave y mar, Santa Fe, Playa, 11300, La Habana, Cuba []
| | - Ohiana Revuelta
- Marine Zoology Unit, Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, 46980 Paterna (Valencia), Spain []
| | - Gonzalo Nodarse
- Marina Marlin Cayo Largo, Isla de la Juventud, 25100, Cuba [; ]
| | - Yosvani Medina
- Marina Marlin Cayo Largo, Isla de la Juventud, 25100, Cuba [; ]
| | - Anyell Caderno
- Department of Biology, Faculty of Marine and Environmental Sciences, University of Cadiz, Avda. de la Universidad, 11510 Puerto Real, Cádiz, Spain. Campus of International Excellence of the Sea (CEIMAR) []
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Martínez-Estévez L, Steller DL, Zilliacus KM, Cuevas Amador JP, Amador FC, Szuta D, Miller SD, Dayton GH, Tershy BR, Croll DA. Foraging ecology of critically endangered Eastern Pacific hawksbill sea turtles (Eretmochelys imbricata) in the Gulf of California, Mexico. MARINE ENVIRONMENTAL RESEARCH 2022; 174:105532. [PMID: 35032818 DOI: 10.1016/j.marenvres.2021.105532] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/14/2021] [Accepted: 11/21/2021] [Indexed: 06/14/2023]
Abstract
The Eastern Pacific hawksbill sea turtle population is one of the most endangered of all sea turtle species. Here, we examine the foraging ecology of 47 hawksbill turtles (40.5-90.3 cm CCL, mean = 54.1 ± 10.1 cm) around Isla San José, Gulf of California, Mexico by integrating information from passive acoustic telemetry, behavior recordings, fecal analysis, and habitat surveys. Tagged hawkbill turtles exhibited high site fidelity over months and years (tracking duration 1-1490 days, mean = 255 ± 373 days) to the location and benthic habitat where individuals were initially caught. Diet was dominated by benthic invertebrates and algae including sponges, algae, tunicates, and mangrove roots. The mean percent cover of these benthic food items was significantly greater in the mangrove estuary than in adjacent rocky and sandy reef habitats. The Isla San José foraging ground is a high-use area for hawksbills and should be granted national protection status.
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Affiliation(s)
- Lourdes Martínez-Estévez
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, 95050, USA.
| | - Diana L Steller
- Moss Landing Marine Laboratories, Moss Landing, CA, 95039, USA
| | - Kelly M Zilliacus
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, 95050, USA
| | | | | | - Dorota Szuta
- Moss Landing Marine Laboratories, Moss Landing, CA, 95039, USA
| | - Scott D Miller
- Department of Biological Sciences, Florida State University, Tallahassee, FL, 32306, USA
| | - Gage H Dayton
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, 95050, USA
| | - Bernie R Tershy
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, 95050, USA
| | - Donald A Croll
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, 95050, USA
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Martinez-Estevez L, Amador JPC, Amador FC, Zilliacus KM, Pacheco AM, Seminoff JA, Lucero J, Oceguera K, Tershy BR, Croll DA. Spatial ecology of hawksbill sea turtles (Eretmochelys imbricata) in foraging habitats of the Gulf of California, Mexico. Glob Ecol Conserv 2021. [DOI: 10.1016/j.gecco.2021.e01540] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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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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Tracking foraging green turtles in the Republic of the Congo: insights into spatial ecology from a data poor region. ORYX 2020. [DOI: 10.1017/s0030605319000309] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
AbstractGlobally, marine turtles are considered threatened throughout their range, and therefore conservation practitioners are increasingly investing resources in marine protected areas to protect key life history stages and critical habitats, including foraging grounds, nesting beaches and inter-nesting areas. Empirical data on the distribution of these habitats and/or the spatial ecology and behaviour of individuals of many marine turtle populations are often lacking, undermining conservation efforts, particularly along the Atlantic coast of Africa. Here we contribute to the knowledge base in this region by describing patterns of habitat use for nine green turtles Chelonia mydas tagged with satellite platform transmitter terminals at a foraging ground in Loango Bay, Republic of the Congo, one of only a few documented mainland foraging grounds for marine turtles in Central Africa. Analyses of these data revealed that core areas of habitat use and occupancy for a wide range of size/age classes were restricted to shallow waters adjacent to Pointe Indienne in Loango Bay, with most individuals showing periods of high fidelity to this area. These data are timely given the Congolese government recently announced its intention to create a marine conservation zone to protect marine turtles in Loango Bay. Despite the small sample size of this study, these data exemplify the need for comprehensive strategies that span national jurisdictions, as we provide the first documented evidence of linkages between green turtle foraging sites in Central Africa (Loango Bay, Republic of the Congo) and Southern Africa (Mussulo Bay, Angola).
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Chambault P, Dalleau M, Nicet JB, Mouquet P, Ballorain K, Jean C, Ciccione S, Bourjea J. Contrasted habitats and individual plasticity drive the fine scale movements of juvenile green turtles in coastal ecosystems. MOVEMENT ECOLOGY 2020; 8:1. [PMID: 31921423 PMCID: PMC6947949 DOI: 10.1186/s40462-019-0184-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 11/28/2019] [Indexed: 05/08/2023]
Abstract
BACKGROUND A strong behavioural plasticity is commonly evidenced in the movements of marine megafauna species, and it might be related to an adaptation to local conditions of the habitat. One way to investigate such behavioural plasticity is to satellite track a large number of individuals from contrasting foraging grounds, but despite recent advances in satellite telemetry techniques, such studies are still very limited in sea turtles. METHODS From 2010 to 2018, 49 juvenile green turtles were satellite tracked from five contrasting feeding grounds located in the South-West Indian Ocean in order to (1) assess the diel patterns in their movements, (2) investigate the inter-individual and inter-site variability, and (3) explore the drivers of their daily movements using both static (habitat type and bathymetry) and dynamic variables (daily and tidal cycles). RESULTS Despite similarities observed in four feeding grounds (a diel pattern with a decreased distance to shore and smaller home ranges at night), contrasted habitats (e.g. mangrove, reef flat, fore-reef, terrace) associated with different resources (coral, seagrass, algae) were used in each island. CONCLUSIONS Juvenile green turtles in the South-West Indian Ocean show different responses to contrasting environmental conditions - both natural (habitat type and tidal cycle) and anthropogenic (urbanised vs. uninhabited island) demonstrating the ability to adapt to modification of habitat.
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Affiliation(s)
- Philippine Chambault
- UMR MARBEC, IFREMER, CNRS, IRD, University of Montpellier, Avenue Jean Monnet, 34200 Sète, France
| | - Mayeul Dalleau
- Centre d’Etude et de Découverte des Tortues Marines (CEDTM), 6 chemin Dubuisson, Appt. 5, 97436 Saint-Leu, La Réunion France
| | - Jean-Benoît Nicet
- GIE MAREX, 697 Chemin Surprise, La Fontaine, 97436 Saint Leu, La Réunion France
| | - Pascal Mouquet
- Université de La Réunion/UMR ESPACE-DEV, Antenne SEAS-OI, 40 Avenue de Soweto, 97410 Saint-Pierre, La Réunion France
| | - Katia Ballorain
- Centre d’Etude et de Découverte des Tortues Marines (CEDTM), 6 chemin Dubuisson, Appt. 5, 97436 Saint-Leu, La Réunion France
- Biodiversity French Agency, Mayotte and Glorieuses Marine Nature Parks, 6 chemin Dubuisson, Appt. 5, 97436 Saint-Leu, La Réunion France
| | - Claire Jean
- Kelonia, l’observatoire des tortues marines, 46 rue du Général de Gaulle, 97436 Saint Leu, La Réunion France
| | - Stéphane Ciccione
- Kelonia, l’observatoire des tortues marines, 46 rue du Général de Gaulle, 97436 Saint Leu, La Réunion France
| | - Jérôme Bourjea
- UMR MARBEC, IFREMER, CNRS, IRD, University of Montpellier, Avenue Jean Monnet, 34200 Sète, France
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Bellini C, Santos AJB, Patrício AR, Bortolon LFW, Godley BJ, Marcovaldi MA, Tilley D, Colman LP. Distribution and growth rates of immature hawksbill turtles Eretmochelys imbricata in Fernando de Noronha, Brazil. ENDANGER SPECIES RES 2019. [DOI: 10.3354/esr00979] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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10
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Selby TH, Hart KM, Smith BJ, Pollock CG, Hillis-Starr Z, Oli MK. Juvenile hawksbill residency and habitat use within a Caribbean marine protected area. ENDANGER SPECIES RES 2019. [DOI: 10.3354/esr00975] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Wildermann NE, Gredzens C, Avens L, Barrios-Garrido HA, Bell I, Blumenthal J, Bolten AB, Braun McNeill J, Casale P, Di Domenico M, Domit C, Epperly SP, Godfrey MH, Godley BJ, González-Carman V, Hamann M, Hart KM, Ishihara T, Mansfield KL, Metz TL, Miller JD, Pilcher NJ, Read MA, Sasso C, Seminoff JA, Seney EE, Willard AS, Tomás J, Vélez-Rubio GM, Ware M, Williams JL, Wyneken J, Fuentes MMPB. Informing research priorities for immature sea turtles through expert elicitation. ENDANGER SPECIES RES 2018. [DOI: 10.3354/esr00916] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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