Simulation of ecological and economic impacts of distant water fleets on Namibian fisheries

This paper analyses the impact of the activities of distant water fleets on Namibia's marine ecosystem through the use of simulation modeling. Mass-balance trophic models and economic valuation techniques are combined to simulate the 'with' and 'without' distant water fleet (DWF) scenarios for two decades prior to Namibia's independence in 1990. Our modeling effort and assumptions lead to two key results. First, because of the activities of the DWFs in this period, Namibia inherited an ecosystem well below its productive capacity. In addition, the ecosystem seems to have been altered by heavy fishing on the three main exploited species (hake, horse mackerel and sardine). Second, fishing by DWFs appears to have led to a loss of similar to 50% of the economic rent that could have been obtained by Namibia from the three key species from 1970 to 1990. The reason for the latter result is that, ceteris paribus, in the absence of the DWFs, the domestic fleet would have benefited from exploiting a much healthier stock at lower costs. (C) 2000 Elsevier Science B.V. All rights reserved.