Fisheries Research Articles

Document Type

Article

Publication Date

2-27-2012

Journal Title

PLoS ONE

ISSN

Electronic: 1932-6203

Keywords

Sharks, Chondrichthyes, Fish physiology, Fisheries, Dogfish, Fish, Fisheries science, Physiological parameters Shark fishery, commercial fisheries, Post-capture survival (PCS), Discarded species

Disciplines

Aquaculture and Fisheries | Management Sciences and Quantitative Methods | Marine Biology | Natural Resource Economics | Natural Resources and Conservation | Natural Resources Management and Policy | Operations and Supply Chain Management | Sustainability

Abstract

Most sharks, rays and chimaeras (chondrichthyans) taken in commercial fisheries are discarded (i.e. returned to the ocean either dead or alive). Quantifying the post-capture survival (PCS) of discarded species is therefore essential for the improved management and conservation of this group. For all chondrichthyans taken in the main shark fishery of Australia, we quantified the immediate PCS of individuals reaching the deck of commercial shark gillnet fishing vessels and applied a risk-based method to semi-quantitatively determine delayed and total PCS. Estimates of immediate, delayed and total PCS were consistent, being very high for the most commonly discarded species (Port Jackson shark, Australian swellshark, and spikey dogfish) and low for the most important commercial species (gummy and school sharks). Increasing gillnet soak time or water temperature significantly decreased PCS. Chondrichthyans with bottom-dwelling habits had the highest PCS whereas those with pelagic habits had the lowest PCS. The risk-based approach can be easily implemented as a standard practice of on-board observing programs, providing a convenient first-step assessment of the PCS of all species taken in commercial fisheries.

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