Update regarding the calibration factors for the two hake species between the two gear types used on the Africana
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2009
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University of Cape Town
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Abstract
In June 2003, the trawl gear on the Africana was changed and a species-dependent multiplicative bias factor q is taken to apply to the surveys conducted with the new gear. Calibration experiments have been conducted between the Africana with the old gear (hereafter referred to as the “old Africana”) and the Nansen, and between the Africana with the new gear (“new Africana”) and the Nansen, in order to provide a basis to relate the multiplicative biases of the Africana with the two types of gear ( old q and new q ). A GLM analysis assuming negative binomial distributions for the catches made (Brandão et al., 2004) provided the following estimates:
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Reference:
Rademeyer, R. A., & Butterworth, D. S. (2009). Update regarding the calibration factors for the two hake species between the two gear types used on the Africana. MARAM: University of Cape Town.