Browsing by Author "Ellis, Jim R."
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- 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.
- Ecophysiological effects of mercury bioaccumulation and biochemical stress in the deep-water mesopredator Etmopterus spinax (Elasmobranchii; Etmopteridae)Publication . Rodrigues, Andreia C.M.; Gravato, Carlos; Galvão, Daniela; Silva, Virgília S.; Soares, Amadeu M.V.M.; Gonçalves, Jorge Manuel Santos; Ellis, Jim R.; Vieira, Rui P.Mercury (Hg) is a non-essential metal that can have toxic effects on the fitness of organisms and tends to bioaccumulate with age and to biomagnify in higher trophic levels. Few studies have assessed oxidative stress and neurotoxicity in deep-water sharks. This study evaluated early ontogenetic changes and physiological effects (antioxidant defences, oxidative damage, aerobic metabolism and neurotransmission functions) of Hg accumulation in the white muscle and brain tissues of the velvet belly lantern shark Etmopterus spinax from the southern Iberian coast (NE Atlantic). Results suggested that the low mercury concentrations observed may induce acute effects in E. spinax before they reach sexual maturity. We found different Hg concentrations in E. spinax: [Hg] males > [Hg] females; [Hg] muscle > [Hg] brain. Females appeared to have higher redox capability translated into higher activities and levels of antioxidant defences than males. However, higher levels of oxidative damage were also observed in females. Whilst the mechanisms underlying these effects remain unknown, these results suggest differences in mercury accumulation between tissues and sex, and potentially deleterious effects on oxidative stress status and neurophysiology of E. spinax, potentially impairing swimming performance and reproduction, which could subsequently impact on the health of both individuals and population.
- Technical mitigation measures for sharks and rays in fisheries for tuna and tuna-like species: turning possibility into realityPublication . Poisson, François; Crespo, Francisco Abascal; Ellis, Jim R.; Chavance, Pierre; Bach, Pascal; Santos, Miguel. N.; Séret, Bernard; Korta, Maria; Coelho, Rui; Ariz, Javier; Murua, HilarioTuna fisheries have been identified as one of the major threats to populations of other marine vertebrates, including sea turtles, sharks, seabirds and marine mammals. The development of technical mitigation measures (MM) in fisheries is part of the code of conduct for responsible fisheries. An in-depth analysis of the available literature regarding bycatch mitigation in tuna fisheries with special reference to elasmobranchs was undertaken. Studies highlighting promising MMs were reviewed for four tuna fisheries (longline, purse seine, driftnets and gillnet, and rod and line – including recreational fisheries). The advantages and disadvantages of different MMs are discussed and assessed based on current scientific knowledge. Current management measures for sharks and rays in tuna Regional Fishery Management Organizations (t-RFMOs) are presented. A review of relevant studies examining at-vessel and postrelease mortality of elasmobranch bycatch is provided. This review aims to help fisheries managers identify pragmatic solutions to reduce mortality on pelagic elasmobranchs (and other higher vertebrates) whilst minimizing impacts on catches of target tuna species. Recent research efforts have identified several effective MMs that, if endorsed by t-RFMOs, could reduce elasmobranchs mortality rate in international tropical purse seine tuna fisheries. In the case of longline fisheries, the number of operational effective MMs is very limited. Fisheries deploying driftnets in pelagic ecosystems are suspected to have a high elasmobranchs bycatch and their discard survival is uncertain, but no effective MMs have been field validated for these fisheries. The precautionary bans of such gear by the EU and by some t-RFMOs seem therefore appropriate. Recreational tuna fisheries should be accompanied by science-based support to reduce potential negative impacts on shark populations. Priorities for research and management are identified and discussed.