Etude des peuplements piscicoles de la retenue de barrage de Sidi Barrak

Abstract

The study of fish populations in reservoirs is essential for sustainable management of the freshwater fisheries. The sampling technique used was based on the European standard CEN prEN 14757. This technique (multi-mesh gillnets) was adapted to Tunisian dams. A stratified random sampling was implemented according to the depth and area of the dam. Samplings were conducted in Sidi Barrak reservoir between November and December 2013. The fish communities were composed by 4 species: barbell, pike-perch, and two species of mullet (Liza ramada and Mugil cephalus). The of weight yield was average and it was low numerically (53 ind / 1000m² and 18Kg / 1000m2). The majority of catches were obtained at depths less than 20m. All fish caught are adults. Populations of Mullet and pike-perch show a strong deficit indicating a state of over-exploitation or insufficiency of stocking. Sidi Barrak reservoir has a well balanced and abundant population of barbell. However, this dam presents a remarkable deficiency of carnivorous fish and forage fish. Diversity indices indicate a little diversity in this dam. Additionally, we identified that the stock of mullet was declining and of eels was lack in this survey. This reservoir required a support from fisheries managers.