Vulnerability of oceanic sharks as pelagic longline bycatch

A. J. Gallagher, E. S. Orbesen, Neil Hammerschlag, J. E. Serafy

Research output: Contribution to journalArticle

47 Citations (Scopus)

Abstract

Bycatch (the unintentional catch of non-target species or sizes) is consistently ranked as one of the greatest threats to marine fish populations; yet species-specific rates of bycatch survival are rarely considered in risk assessments. Regulations often require that bycatch of threatened species be released; but, if animals are already dead, their release serves no conservation purpose. We examined the survival of 12 shark species caught as bycatch in the US Atlantic pelagic longline fishery. Shark survival was evaluated in relation to fishery target (swordfish versus tuna) and four operational, environmental, and biological variables to evaluate the underlying mechanisms affecting mortality. Survival estimates ranged from 33% (night shark) to 97% (tiger shark) with seven of the 12 species being significantly affected by at least one variable. We placed our survival results within a framework that assessed each species' relative vulnerability by integrating survival estimates with reproductive potential and found that the bigeye thresher, dusky, night, and scalloped hammerhead shark exhibited the highest vulnerabilities to bycatch. We suggest that considering ecological and biological traits of species shows promise for designing effective conservation measures, whereas techniques that reduce fisheries interactions in the first place may be the best strategy for highly vulnerable species.

Original languageEnglish
Pages (from-to)50-59
Number of pages10
JournalGlobal Ecology and Conservation
Volume1
DOIs
StatePublished - Jan 1 2014

Fingerprint

bycatch
shark
sharks
vulnerability
fisheries
Galeocerdo cuvier
Sphyrnidae
Xiphias gladius
nontarget organisms
tuna
threatened species
marine fish
fishery
risk assessment
pelagic fishery
reproductive potential
animals
mortality
animal
fish

Keywords

  • Bycatch
  • Fisheries
  • Shark
  • Stress
  • Sustainability
  • Vulnerability

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology
  • Nature and Landscape Conservation

Cite this

Vulnerability of oceanic sharks as pelagic longline bycatch. / Gallagher, A. J.; Orbesen, E. S.; Hammerschlag, Neil; Serafy, J. E.

In: Global Ecology and Conservation, Vol. 1, 01.01.2014, p. 50-59.

Research output: Contribution to journalArticle

Gallagher, A. J. ; Orbesen, E. S. ; Hammerschlag, Neil ; Serafy, J. E. / Vulnerability of oceanic sharks as pelagic longline bycatch. In: Global Ecology and Conservation. 2014 ; Vol. 1. pp. 50-59.
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