Bottom trawl codend mesh selectivity for Bagrus docmac (Forskahl) from Lake Victoria, with some remarks on the proposed trawl fishery

The methods of estimating codend selectivity for alternate hauls are briefly described and applied to Bagrus docmac (forskahl) data from Lake Victoria. Certain inconsistencies are noted and it is postulated that they may be due to differential escapement of larger Bagrus docmac through the trawl meshes when the different codends were fitted. The calculated 50% selection lengths yielded a fair regression on measured weigh give a fork length selection factor of 2.33, consistent with data from the smallest codend mesh size used. The implications of the findings are briefly discussed in relation to the proposed Haplochromis trawl fishery 1971.