Browsing by Author "Hawkes, Lucy A."
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- Biochemical indices and life traits of loggerhead turtles (Caretta caretta) from Cape Verde IslandsPublication . Vieira, Sara; Martins, Samir; Hawkes, Lucy A.; Marco, Adolfo; Chicharo, AlexandraThe loggerhead turtle (Caretta caretta) is an endangered marine reptile for whom assessing population health requires knowledge of demographic parameters such as individual growth rate. In Cape Verde, as within several populations, adult female loggerhead sea turtles show a size-related behavioral and trophic dichotomy. While smaller females are associated with oceanic habitats, larger females tend to feed in neritic habitats, which is reflected in their physiological condition and in their offspring. The ratio of RNA/DNA provides a measure of cellular protein synthesis capacity, which varies depending on changes in environmental conditions such as temperature and food availability. The purpose of this study was to evaluate the combined use of morphometric data and biochemical indices as predictors of the physiological condition of the females of distinct sizes and hatchlings during their nesting season and how temperature may influence the physiological condition on the offspring. Here we employed biochemical indices based on nucleic acid derived indices (standardized RNA/DNA ratio-sRD, RNA concentration and DNA concentration) in skin tissue as a potential predictor of recent growth rate in nesting females and hatchling loggerhead turtles. Our major findings were that the physiological condition of all nesting females (sRD) decreased during the nesting season, but that females associated with neritic habitats had a higher physiological condition than females associated with oceanic habitats. In addition, the amount of time required for a hatchling to right itself was negatively correlated with its physiological condition (sRD) and shaded nests produced hatchlings with lower sRD. Overall, our results showed that nucleic acid concentrations and ratios of RNA to DNA are an important tool as potential biomarkers of recent growth in marine turtles. Hence, as biochemical indices of instantaneous growth are likely temperature-, size- and age-dependent, the utility and validation of these indices on marine turtles stocks deserves further study.
- Diving into the vertical dimension of elasmobranch movement ecologyPublication . Andrzejaczek, Samantha; Lucas, Tim C. D.; Goodman, Maurice C.; Hussey, Nigel E.; Armstrong, Amelia J.; Carlisle, Aaron; Coffey, Daniel M.; Gleiss, Adrian C.; Huveneers, Charlie; Jacoby, David M. P.; Meekan, Mark G.; Daly, Ryan; Dewar, Heidi; Doherty, Philip D.; McAllister, Jaime D.; Domingo, Andrés; Dove, Alistair D. M.; Drew, Michael; Dudgeon, Christine L.; Duffy, Clinton A. J.; Elliott, Riley G.; Papastamtiou, Yannis P.; Ellis, Jim R.; Erdmann, Mark V.; Farrugia, Thomas J.; Ferreira, Luciana C.; McCully Phillips, Sophy R.; Ferretti, Francesco; Filmalter, John D.; Finucci, Brittany; Fischer, Chris; Fitzpatrick, Richard; Patterson, Toby A.; Forget, Fabien; Forsberg, Kerstin; Francis, Malcolm P.; Franks, Bryan R.; Gallagher, Austin J.; McGregor, Frazer; Galvan-Magana, Felipe; García, Mirta L.; Gaston, Troy F.; Gillanders, Bronwyn M.; Pierce, Simon J.; Gollock, Matthew J.; Green, Jonathan R.; Green, Sofia; Griffiths, Christopher A.; Hammerschlag, Neil; Hasan, Abdi; McMillan, Matthew N.; Hawkes, Lucy A.; Hazin, Fabio; Heard, Matthew; Peel, Lauren R.; Hearn, Alex; Hedges, Kevin J.; Henderson, Suzanne M.; Holdsworth, John; Holland, Kim N.; Howey, Lucy A.; Hueter, Robert E.; McNaughton, Lianne M.; Humphries, Nicholas E.; Hutchinson, Melanie; Queiroz, Nuno; Jaine, Fabrice R. A.; Jorgensen, Salvador J.; Kanive, Paul E.; Labaja, Jessica; Lana, Fernanda O.; Lassauce, Hugo; Lipscombe, Rebecca S.; Llewellyn, Fiona; Mendonça, Sibele A.; Macena, Bruno C. L.; Radford, Craig A.; Meyer, Carl G.; Meyers, Megan; Mohan, John A.; Mourier, Johann; Montgomery, John C.; Mucientes, Gonzalo; Musyl, Michael K.; Nasby-Lucas, Nicole; Natanson, Lisa J.; O’Sullivan, John B.; Richardson, Andy J.; Oliveira, Paulo; Richardson, Anthony J.; Righton, David; Rohner, Christoph A.; Brooks, Edward J.; Royer, Mark A.; Saunders, Ryan A.; Schaber, Matthias; Schallert, Robert J.; Abrantes, Kátya; Scholl, Michael C.; Seitz, Andrew C.; Semmens, Jayson M.; Setyawan, Edy; Shea, Brendan D.; Brown, Judith; Shidqi, Rafid A.; Shillinger, George L.; Shipley, Oliver N.; Shivji, Mahmood S.; Sianipar, Abraham B.; Afonso, André S.; Silva, Joana F.; Sims, David W.; Skomal, Gregory B.; Sousa, Lara L.; Burke, Patrick J.; Southall, Emily J.; Spaet, Julia L. Y.; Stehfest, Kilian M.; Stevens, Guy; Stewart, Joshua D.; Sulikowski, James A.; Ajemian, Matthew J.; Syakurachman, Ismail; Thorrold, Simon R.; Thums, Michele; Butcher, Paul; Tickler, David; Tolloti, Mariana T.; Townsend, Kathy A.; Travassos, Paulo; Tyminski, John P.; Vaudo, Jeremy J.; Veras, Drausio; Anderson, Brooke N.; Wantiez, Laurent; Weber, Sam B.; Castleton, Michael; Wells, R.J. David; Weng, Kevin C.; Wetherbee, Bradley M.; Williamson, Jane E.; Witt, Matthew J.; Wright, Serena; Zilliacus, Kelly; Block, Barbara A.; Anderson, Scot D.; Curnick, David J.; Chapple, Taylor K.; Araujo, Gonzalo; Armstrong, Asia O.; Bach, Pascal; Barnett, Adam; Bennett, Mike B.; Bezerra, Natalia A.; Bonfil, Ramon; Boustany, Andre M.; Bowlby, Heather D.; Branco, Ilka; Chateau, Olivier; Braun, Camrin D.; Clarke, Maurice; Coelho, Rui; Cortes, Enric; Mambrasar, Ronald; Couturier, Lydie I. E.; Cowley, Paul D.; Croll, Donald A.; Cuevas, Juan M.; Curtis, Tobey H.; Dagorn, Laurent; Dale, Jonathan J.Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements.
- Green and hawksbill sea turtles of Eastern Atlantic: new insights into a globally important rookery in the Gulf of GuineaPublication . Ferreira-Airaud, Betania; Vieira, Sara; Branco, Maria; Pina, Antunes; Soares, Venceslau; Tiwari, Manjula; Witt, Matthew; Castilho, Rita; Teodosio, Maria; Hawkes, Lucy A.Sea turtles are critical components of marine ecosystems, and their conservation is important for Ocean Governance and Global Planet Health. However, there is limited knowledge of their ecology in the Gulf of Guinea. To fill this knowledge gap, this study presents the first integrative assessment of green and hawksbill turtles in the region, combining nesting surveys over 9 years and telemetry data, to offer insights into these population dynamics, and behaviours, including nesting preferences, morphological and reproductive parameters, diving patterns and inter-nesting core-use areas. Both green and hawksbill turtles are likely making a recovery on Sao Tome, potentially driven by sustained conservation efforts. There are preliminary indications of recovery, but we interpret this cautiously. Coupled with satellite tracking, this study estimated that 482 to 736 green turtles and 135 to 217 hawksbills nest on the beaches of Sao Tome. Their movements overlap significantly with a proposed Marine Protected Area (MPA), which suggests they may be well placed for conservation if managed appropriately. However, the presence of artisanal fisheries and emerging threats, such as sand mining and unregulated tourism, highlight the urgent need for robust management strategies that align global conservation objectives with local socioeconomic realities. This study significantly enhances our understanding of the ecology and conservation needs of the green and hawksbill turtles in the Gulf of Guinea. The insights gleaned here can contribute to the development of tailored conservation strategies that benefit these populations and the ecosystem services upon which they depend. This study presents a comprehensive assessment of green and hawksbill sea turtles in the Gulf of Guinea, combining 9 years of nesting area surveys with telemetry data. Our findings reveal promising signs of recovery for green and hawksbill turtles, driven by conservation efforts. Our research underscores the importance of effective conservation strategies, especially in the face of emerging threats, to protect these vital marine species and their ecosystems in the Eastern Atlantic.image
- Green and Hawksbill sea turtles of Eastern Atlantic: new insights into a globally important rookery in the Gulf of GuineaPublication . Ferreira-Airaud, Betânia; Vieira, Sara; Branco, Maria; Pina, Antunes; Soares, Venceslau; Tiwari, Manjula; Witt, Matthew; Castilho, Rita; Teodosio, Maria; Hawkes, Lucy A.Sea turtles are critical components of marine ecosystems, and their conservation is important for Ocean Governance and Global Planet Health. However, there is limited knowledge of their ecology in the Gulf of Guinea. To fill this knowledge gap, this study presents the first integrative assessment of green and hawksbill turtles in the region, combining nesting surveys over 9 years and telemetry data, to offer insights into these population dynamics, and behaviours, including nesting preferences, morphological and reproductive parameters, diving patterns and inter-nesting core-use areas. Both green and hawksbill turtles are likely making a recovery on São Tomé, potentially driven by sustained conservation efforts. There are preliminary indications of recovery, but we interpret this cautiously. Coupled with satellite tracking, this study estimated that 482 to 736 green turtles and 135 to 217 hawksbills nest on the beaches of São Tomé. Their movements overlap significantly with a proposed Marine Protected Area (MPA), which suggests they may be well placed for conservation if managed appropriately. However, the presence of artisanal fisheries and emerging threats, such as sand mining and unregulated tourism, highlight the urgent need for robust management strategies that align global conservation objectives with local socioeconomic realities. This study significantly enhances our understanding of the ecology and conservation needs of the green and hawksbill turtles in the Gulf of Guinea. The insights gleaned here can contribute to the development of tailored conservation strategies that benefit these populations and the ecosystem services upon which they depend.