| The purpose of this study was an assessment of distributional patterns, exploitation level and value of commercial important bycatch species in the Namibian demersal fishery. Alternative management policies were to be recommended.; The data used in the study was from the fishery independent surveys conducted by the Norwegian R/V Dr. Fridtjof Nansen (1990--1999) and a Namibian commercial chartered vessel (2000). Landing data for 1994 to 1999 was also used.; The study investigated the spatio-temporal distributions of commercially important bycatch species in the demersal fishery of Namibia. Technical interaction of demersal and midwater trawl fleet was investigated. The abundance and economic value of currently non-exploitable bycatch was assessed.; Large-eye-dentex (Dentex macrophthalmus) depicted an exclusive northerly distribution. The distributional pattern of this species was heterogeneous dominated by sparse strata. Kingklip (Genypterus capensis) has been found represented in the south and central regions in a non-concentrated manner. Horse mackerel (Trachurus capensis) and jacopever (H. dactylopterus) have been found to be heterogeneous in distribution. These species were common at depths in excess of 350m and widespread in the Namibian waters. Monk (Lophius) and sole (Austroglossus) species were sporadic in nature. There were no significant differences in the temporal distribution of the bycatch species except for the years of anomalic environmental conditions (1994 to 1995). The cumulative exploitation of target bycatch species (hake, horse mackerel and sole) has been under the designated TACs, thus there were no signs of overexploitation for these species. However, monk (Lophius) species has been overexploited from 1994 to 1999. This pattern of overexploitation could culminate in depletion of the stock. The net value for target bycatch species continued to increase within the target fisheries and either declined or remained constant in alternative fisheries. Non-target bycatch species (large-eye-dentex, kingklip, jacopever and Angolan flying squid) have been incidentally harvested below their maximum sustainable yield from 1994 to 1999 and this implied that overexploitation of these species was not prevalent. When revenues under current bycatch policies were compared to one with individually transferable quotas in concert with quota substitution for 1995 to 1999 for the demersal fishery it was concluded that a change in policy would result in higher total revenues and profits. |
