Instruments and data aquisition systems for research on trawl nets

Catching methods and ways to improve them have been engaging the attention of fishermen from time immemorial. This was done mostly by trial and error methods, as most of the earlier investigations were primarily directed towards solution of biological problems related to fisheries. In recent years several fisheries laboratories have taken up studies on the working principles of many gears such as trawls, gill nets, round haul nets etc. with the aid of instruments developed for the purpose. The purpose of this article is to review the progress made in this field and in the development of telemetering instruments and continuous data acquisition systems.

Final report of the targeted research on Indian mackerel and sharks and national plan of action for conservation and management of shark resources, Thailand

Research included: population structure of Indian mackerel (Rastrelliger kanagurta); a National Plan of Action for the conservation and management of sharks; levels of heavy metals in shark products; and a database on rays.

Past trends and recent research on the fisheries of Lake Victoria in relation to possible future developments

EAFFRO and UNPP/LVFRP bottom trawl exploratory data have been used to describe the depth distributional pattern. relative abundance and magnitude of the demersai fishes in Lake Victoria. The results have been compared with the commercial catch estimates, and various interpretations of the trends in the annual catches and experimental biomass estimates in relation to possible future developments of the fishery have been suggested. Though it is highly desirable to develop the fishery such as by supplementary trawling, certain social and biological consequences and considerations needs to proceed in graded steps guided by several research disciplines. The past trends of the fisheries of Lake Victoria are briefly considered. Recent exploratory bottom trawl data, by EAFFRO and UNDP/LVFRP, have been used to define demersal fish stocks of Lake Victoria in terms of their magnitude, relative abundance and distribution pattern by depth. Enstence of disparity between the relative abundance of the various species in their commercial catches and in their present biomass estimates is pointed out and the various aspects associated with the necessary modification of the fishing practices are discussed. Further and continuing research of the bio-socio-economic vectors of the fishery will be necessary in order to generate the rationale of an efficient fishing regime for a rational management strategy and realistic utilization of the fishery resource.