Evaluation of the Status of the Namibian Hake Resource (Merluccius spp.) Using Statistical Catch-at-Age Analysis

Namibian hake is the most important fish resource in Namibia. This monograph is a compilation of all the hake data, historic and recent, that has been used to inform stock assessment and management since the late 1970s. It presents the statistical catch-at-age analysis used to evaluate the state of the Namibian hake resource under different assumptions. This analysis treats the two hakes, Merluccius paradoxus and M. capensis, as a single stock. The data and modeling show that the stock has not as yet recovered to its maximum sustainable yield level, despite foreign fishing effort having been removed in 1990. Best estimates suggest the current stock to be roughly 20% of pre-exploitation levels; however this figure is sensitive to model assumptions. Signs indicate that the stock is slowly recovering from its all-time low in 2002-2004. Because the two hake species are pooled for assessment, the resource is currently managed on a relatively simple adaptive basis; 80% of the estimated replacement yield is reserved for fishing, the remainder being left for rebuilding.

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Bibliographic Details
Main Authors: Kirchner, Carola, Kainge, Paul, Kathena, Johannes
Format: Book Section biblioteca
Language:English
Published: University of Cape Town 2012
Subjects:Stock assessment, Gadoid fisheries, Data, Dynamics, Surveys, Commercial species, Total allowable catch, Biomass, Trawls, Otoliths, Fishing mortality, Fisheries management, Reproductive system,
Online Access:http://hdl.handle.net/1834/5166
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Summary:Namibian hake is the most important fish resource in Namibia. This monograph is a compilation of all the hake data, historic and recent, that has been used to inform stock assessment and management since the late 1970s. It presents the statistical catch-at-age analysis used to evaluate the state of the Namibian hake resource under different assumptions. This analysis treats the two hakes, Merluccius paradoxus and M. capensis, as a single stock. The data and modeling show that the stock has not as yet recovered to its maximum sustainable yield level, despite foreign fishing effort having been removed in 1990. Best estimates suggest the current stock to be roughly 20% of pre-exploitation levels; however this figure is sensitive to model assumptions. Signs indicate that the stock is slowly recovering from its all-time low in 2002-2004. Because the two hake species are pooled for assessment, the resource is currently managed on a relatively simple adaptive basis; 80% of the estimated replacement yield is reserved for fishing, the remainder being left for rebuilding.