Estimation of annual gillnet ghost fishing mortality on three selected fish landing sites on Lake Victoria

Abstract

Ghost fishing can impose a variety of harmful impacts, including the ability to kill target and non-target organisms, including endangered and protected species; causing damage to underwater habitats such as coral reefs and benthic fauna; and contributing to marine pollution. In Uganda, as well as many other African countries, not much, if not nothing has been studied concerning such a potential disaster to the fisheries and aquaculture sectors. There is therefore scanty or no information on ghost fishing and its negative impacts because it is not accounted for among the sectors‟ statistics. This study concentrated on three of Uganda‟s busiest fish landing site, that is, Katosi, Kiyindi, and Ssenyi, in an attempt to estimate ghost fishing fish mortality due to derelict gillnets for an annual period. Data collection, which lasted a month, was achieved by interview guides directed to fishermen and fisheries officers at the mentioned landing sites. Data was unbiasedly collected by sampling at least ten personalities from each site, who answered each of the questions in the guide through free interaction between them and the researcher. The assessment included reasons for loss of the gillnets, among which theft and entanglement with other gear were outstanding. Comparison of gillnet loss rates, due to each of these two reasons, during the fishing season and the non-season was also assessed using a paired sample T-test, and the results revealed a higher loss incidence during the non-season, for reasons of sale to sponges and rope-makers. Reasons for gillnet loss during the fishing season were associated with intentional theft due to competition. The results further showed that there is highest gillnet ghost fishing mortality at Kiyindi, then Katosi, and lastly Ssenyi with the least. This can be attributed to factors like inefficient follow-up programs to retrieve the lost gear, uncoordinated fishing calendars, and poor fishing methods, among others. There is therefore urgent need to address the issue of not only gillnet, but also loss of other fishing gear. This will enable address the unanticipated low productivity of fish from the fisheries‟ sector at these landing sites, possibly caused due to increased ghost fishing in the fishing grounds.