How much do we know about seabird bycatch in pelagic longline fisheries? A simulation study on the potential bias caused by the usually unobserved portion of seabird bycatch

dc.contributor.authorZhou, Canen
dc.contributor.authorJiao, Yanen
dc.contributor.authorBrowder, Joan A.en
dc.contributor.departmentFish and Wildlife Conservationen
dc.date.accessioned2019-11-15T17:30:21Zen
dc.date.available2019-11-15T17:30:21Zen
dc.date.issued2019-08-05en
dc.description.abstractNot much is known about the fleet level total seabird bycatch from pelagic longlines of United States vessels in the western North Atlantic or other fleets of the Atlantic or other oceans. Onboard observers generally only record seabird bycatch during line hauling. Seabirds are predominantly caught during the line setting stage, and, due to predation or mechanical action, those caught prior to the haul can drop off the hook and be lost to the onboard observer. We developed a model to gauge the size of this bycatch loss problem and provide a first approximation of its impact on estimates of total fleet bycatch. We started with a traditional loss-free bycatch model, which assumes that birds recorded were the only birds captured, and integrated into it two crucial components of the bycatch process: capture origin (set or haul) and bycatch loss of set-captures. We extracted count data on seabird bycatch loss and bycatch mortality from the literature on other longline fisheries and used these data to simulate potential total seabird bycatch in the western North Atlantic. Simulations revealed the shortcomings of both the traditional bycatch model and the current haul-only observer protocol, each of which contributed to biologically significant underestimation of total bycatch and estimation uncertainty. Based on our results, we recommend a loss-corrected modeling approach to provide a more accurate estimate of seabird mortalities in pelagic longline fisheries. Where possible, fishery-specific seabird bycatch loss rates need to be ascertained via specific set and haul observing protocols. But, even where fishery-specific estimates for a region are not available, the methodology developed here is applicable to other pelagic longline fisheries to approximate fleet-level loss-corrected bycatch.en
dc.description.notesThis work received funding from the National Oceanic and Atmospheric Administration National Marine Fisheries Service, Southeast Fisheries Science Center, grant number WC133F15SE1858 (https://www.sefsc.noaa.gov/) to YJ, and funding from National Oceanic and Atmospheric Administration Fisheries' National Seabird Program (https://www.st.nmfs.noaa.gov/national-seabird-program/) to JB and to the Southeast Fisheries Science Center. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The second grant from the National Seabird Program was an internal one, and it doesn't have a grant number.en
dc.description.sponsorshipNational Oceanic and Atmospheric Administration National Marine Fisheries Service, Southeast Fisheries Science Center [WC133F15SE1858]; National Oceanic and Atmospheric Administration Fisheries' National Seabird Program; National Seabird Programen
dc.format.mimetypeapplication/pdfen
dc.identifier.doihttps://doi.org/10.1371/journal.pone.0220797en
dc.identifier.eissn1932-6203en
dc.identifier.issue8en
dc.identifier.othere0220797en
dc.identifier.pmid31381613en
dc.identifier.urihttp://hdl.handle.net/10919/95558en
dc.identifier.volume14en
dc.language.isoenen
dc.publisherPLOSen
dc.rightsCreative Commons Attribution 4.0 Internationalen
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/en
dc.titleHow much do we know about seabird bycatch in pelagic longline fisheries? A simulation study on the potential bias caused by the usually unobserved portion of seabird bycatchen
dc.title.serialPLOS ONEen
dc.typeArticle - Refereeden
dc.type.dcmitypeTexten
dc.type.dcmitypeStillImageen

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