Browsing by Author "Bowlby, Heather D."
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- Beyond post-release mortality: inferences on recovery periods and natural mortality from electronic tagging data for discarded lamnid sharksPublication . Bowlby, Heather D.; Benoît, Hugues P.; Joyce, Warren; Sulikowski, James; Coelho, Rui; Domingo, Andrés; Cortés, Enric; Hazin, Fabio; Macias, David; Biais, Gérard; Casaca Santos, Catarina; Anderson, BrookeAccurately characterizing the biology of a pelagic shark species is critical when assessing its status and resilience to fishing pressure. Natural mortality (M) is well known to be a key parameter determining productivity and resilience, but also one for which estimates are most uncertain. While M can be inferred from life history, validated direct estimates are extremely rare for sharks. Porbeagle (Lamna nasus) and shortfin mako (Isurus oxyrinchus) are presently overfished in the North Atlantic, but there are no directed fisheries and successful live release of bycatch is believed to have increased. Understanding M, post-release mortality (PRM), and variables that affect mortality are necessary for management and effective bycatch mitigation. From 177 deployments of archival satellite tags, we inferred mortality events, characterized physiological recovery periods following release, and applied survival mixture models to assess M and PRM. We also evaluated covariate effects on the duration of any recovery period and PRM to inform mitigation. Although large sample sizes involving extended monitoring periods (>90 days) would be optimal to directly estimate M from survival data, it was possible to constrain estimates and infer probable values for both species. Furthermore, the consistency of M estimates with values derived from longevity information suggests that age determination is relatively accurate for these species. Regarding bycatch mitigation, our analyses suggest that juvenile porbeagle are more susceptible to harm during capture and handling, that keeping lamnid sharks in the water during release is optimal, and that circle hooks are associated with longer recovery periods for shortfin mako.
- 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.
- Global habitat predictions to inform spatiotemporal fisheries management: initial steps within the frameworkPublication . Bowlby, Heather D.; Druon, Jean-Noël; Lopez, Jon; Juan-Jordá, Maria José; Carreón-Zapiain, María Teresa; Vandeperre, Frederic; Leone, Agostino; Finucci, Brittany; Sabarros, Philippe S.; Block, Barbara A.; Arrizabalaga, Haritz; Afonso, Pedro; Musyl, Michael K.; Cortés, Enric; Cardoso, Luis Gustavo; Mourato, Bruno; Queiroz, Nuno; Fontes, Jorge; Abascal, Francisco J.; Zanzi, Antonella; Hazin, Humberto Gomes; Bach, Pascal; Sims, David W.; Travassos, Paulo; Coelho, RuiTuna Regional Fishery Management Organizations (tRFMOs) are increasingly interested in spatiotemporal management as a tool to reduce interaction rates with vulnerable species. We use blue shark ( Prionace glauca ) as a case study to demonstrate the critical first steps in the implementation process, highlighting how predictions of global habitat for vulnerable life stages can be transformed into a publicly -accessible spatial bycatch mitigation tool. By providing examples of possible management goals and an associated threshold to identify essential habitats, we show how these key areas can represent a relatively low percentage of oceanic area on a monthly basis (16-24% between 50 degrees S and 60 degrees N), yet can have relatively high potential protection efficiency (similar to 42%) for vulnerable stages if fishing effort is redistributed elsewhere. While spatiotemporal management has demonstrable potential for blue sharks to effectively mitigate fishing mortality on sensitive life stages, we identify inherent challenges and sequential steps that require careful consideration by tRFMOs as work proceeds. We also discuss how our single-species framework could be easily extended to a multispecies approach by assigning relative conservation risk before layering habitat model predictions in an integrated analysis. Such broader application of our approach could address the goals of tRFMOs related to reducing the ecosystem effects of fishing and pave the way for efficient fisheries co-management using an ecosystem-based approach.
- Preliminary estimate of post-release survival of immature porbeagles caught with rod-and-reel in the Northwest Atlantic OceanPublication . Anderson, Brooke N.; Bowlby, Heather D.; Natanson, Lisa J.; Coelho, Rui; Cortes, Enric; Domingo, Andres; Sulikowski, James A.The Northwest Atlantic (NWA) population of porbeagles Lamna nasus is susceptible to capture in rod-and-reel fisheries and most individuals are discarded alive due to catch and size limits. To estimate post-release survival, pop-off satellite archival tags were attached to porbeagles captured with rod-and-reel. Fourteen tags were deployed, of which 13 transmitted. All sharks for which we had data survived, giving a post-release survival rate of 100%. Following release, 6 individuals remained in surface waters for several hours to days, while 2 individuals immediately resumed normal diving behaviors. For the remaining sharks (n = 5), low tag transmission resolution precluded the detection of fine scale post-release behavior. The duration of initial depth-holding behavior was characterized using a break-point analysis of dive track variance, which suggests porbeagles exhibited a median post-release recovery period of 116 h (10th and 90th percentiles = 68.8 and 280.1 h) following capture and handling. Our preliminary study suggests immature porbeagles are resilient to capture and handling, although more data would provide stronger support for management recommendations.