Research Papers

An alternative method for estimating the status of resident reef fish stocks, based on differential fishing effort across a marine reserve boundary

Published in: African Journal of Marine Science
Volume 33, issue 1, 2011, pages: 107–113
DOI: 10.2989/1814232X.2011.572357
Author(s): A GötzElwandle Node, South Africa, SE KerwathBranch Fisheries, Department of Agriculture, South Africa, CG AttwoodMarine Research Institute, Zoology Department, South Africa, WHH SauerDepartment of Ichthyology and Fisheries Science, South Africa

Abstract

The stock status of roman Chrysoblephus laticeps was estimated in the Goukamma, a temperate South African marine protected area (MPA). Standardised catch per unit effort (CPUE) from a controlled angling survey on both sides of the MPA border was employed to extrapolate the CPUE at zero fishing mortality. Converted into biomass, the estimate (61% of unexploited biomass) lay midway between those of two biomass-per-recruit (B/R) models for the same population based on angling and diving surveys (i.e. 52% and 69% of unexploited biomass respectively). The extrapolated CPUE at zero fishing mortality (4.4 fish angler-hour−1) in this study compared well with the mean CPUE of 4.6 fish angler-hour−1 determined during a concomitant survey in the core area of the nearby Tsitsikamma MPA – the oldest, and one of the largest, MPAs in Africa. Extrapolations of CPUE have the potential to deliver reliable and consistent estimates of stock status and could offer a practical alternative to conventional B/R models.

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