title: Global patterns of marine mammal, seabird, and sea turtle bycatch reveal taxa-specific and cumulative megafauna hotspots.
abstract: Recent research on ocean health has found large predator abundance to be a key element of ocean condition. Fisheries can impact large predator abundance directly through targeted capture and indirectly through incidental capture of nontarget species or bycatch. However, measures of the global nature of bycatch are lacking for air-breathing megafauna. We fill this knowledge gap and present a synoptic global assessment of the distribution and intensity of bycatch of seabirds, marine mammals, and sea turtles based on empirical data from the three most commonly used types of fishing gears worldwide. We identify taxa-specific hotspots of bycatch intensity and find evidence of cumulative impacts across fishing fleets and gears. This global map of bycatch illustrates where data are particularly scarce--in coastal and small-scale fisheries and ocean regions that support developed industrial fisheries and millions of small-scale fishers--and identifies fishing areas where, given the evidence of cumulative hotspots across gear and taxa, traditional species or gear-specific bycatch management and mitigation efforts may be necessary but not sufficient. Given the global distribution of bycatch and the mitigation success achieved by some fleets, the reduction of air-breathing megafauna bycatch is both an urgent and achievable conservation priority.
authors.affiliation: Department of Biology, San Diego State University, San Diego, CA 92182-4614.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Lewison
authors.forename: Larry B
authors.initials: LB
authors.lastname: Crowder
authors.forename: Bryan P
authors.initials: BP
authors.lastname: Wallace
authors.forename: Jeffrey E
authors.initials: JE
authors.lastname: Moore
authors.forename: Tara
authors.initials: T
authors.lastname: Cox
authors.forename: Ramunas
authors.initials: R
authors.lastname: Zydelis
authors.forename: Sara
authors.initials: S
authors.lastname: McDonald
authors.forename: Andrew
authors.initials: A
authors.lastname: DiMatteo
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Dunn
authors.forename: Connie Y
authors.initials: CY
authors.lastname: Kot
authors.forename: Rhema
authors.initials: R
authors.lastname: Bjorkland
authors.forename: Shaleyla
authors.initials: S
authors.lastname: Kelez
authors.forename: Candan
authors.initials: C
authors.lastname: Soykan
authors.forename: Kelly R
authors.initials: KR
authors.lastname: Stewart
authors.forename: Michelle
authors.initials: M
authors.lastname: Sims
authors.forename: Andre
authors.initials: A
authors.lastname: Boustany
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Read
authors.forename: Patrick
authors.initials: P
authors.lastname: Halpin
authors.forename: W J
authors.initials: WJ
authors.lastname: Nichols
authors.forename: Carl
authors.initials: C
authors.lastname: Safina
mesh_terms: D000818:Animals; D044822:Biodiversity; D001717:Birds; D008322:Mammals; D008386:Marine Biology; D014426:Turtles
keywords: fisheries bycatch; gillnets; longlines; trawls; trophic downgrading