地理ジャーナルと自然災害
オープンアクセス

概要

Shift of Small Scale Fishing Impacts on Fish Trophic Levels in Lake Iro Revealed by Species-Based Indicators

Modou Thiaw, Mbaye Tine, Hamet Diaw Diadhiou, Oualbadet Magoma, Patrice Brehmer

A fisheries management plan was required in Central Africa, which integrated a reduced regional hydrographical network and limited amounts of data in the overall regime. The current data and knowledge on fish populations and fisheries impacts are very poor in this region, particularly in Chad. Therefore, any new knowledge, especially on the structure of the ichthyological stands can be considered as valuable. Information on the status of Lake Iro fisheries resources was thus established by this study, which can serve as a model fisheries management regime in Central Africa. We performed assessment of fish resources in Lake Iro, Chad, achieved by a characterization of the exploited ichthyofauna, and the location of nursery and fishing areas. Results indicated that the overall size range of fish species showed negative effects of fishing pressure on size structure of the fish resources. Fishing has increasingly exerted pressure on fish species and affected the primary consumer species. We hypothesized at Lake Iro fish catches were below optimal fish production levels, essentially due to excessive localized fishing efforts, and selective fishing techniques by fisherman. Such reports call for the development of an integrated plan for sustainable management of Lake Iro fisheries resources. Sustainable and equitable exploitation of Lake Iro resources can be promoted by implementation of the following recommendation: a protected area at the lake inlet to limit excessive juvenile fish catches, which disturbs the aquatic food chain and prevents juvenile fish supply and growth in Lake Iro.