Assessment of the toothfish (Dissostichus eleginoides) resource in the Prince Edward Islands vicinity to include data from 1997 to 2013

Brandão, Anabela; Butterworth, Doug S

Assessment of the toothfish (Dissostichus eleginoides) resource in the Prince Edward Islands vicinity to include data from 1997 to 2013

Working Paper

2013

Publisher

University of Cape Town

Department

Marine Resource Assessment and Management Group

Faculty

Faculty of Science

Abstract

The ASPM assessment of the Prince Edward Islands toothfish resource by Brandão and Butterworth (2007) that permitted annual fluctuations about a deterministic stockrecruitment relationship is updated to take account of further catch, GLMM standardised CPUE and catch-at-length information that has become available for the years 2007 to 2013. The assessment allows for three fleets to accommodate data from a pot fishery that operated in 2004 and 2005 and a trotline fishery since 2008 in addition to the Spanish longline operations. Biological parameter values adopted for Subarea 48.3 are used. The resource is estimated to be at a depletion of about 87% of its average pre-exploitation level in terms of spawning biomass, but this requires large recruitment pulses in the 1990s and does not reflect the large CPUE decline when the fishery commenced. Imposing alternative constraints lead to a depletion of about 43%. These different assessments imply rather different sustainable yields, though all suggest medium term abundance increases for a TAC of 500 t.

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