Resultado de diferentes medidas de manejo tendientes a optimizar la pesquería de pejerrey (Odontesthes bonariensis) en la laguna Cochicó, Argentina

The Cochicó shallow lake is part of the Encadenadas del Oeste system (Buenos Aires province, Argentina). Since 2000, the municipal state has been conducting intensive tasks to supplement silverside (Odontesthes bonariensis) fisheries stock by seeding and furtive fishing control, as part of the strategy to improve and protect the resource, in order to achieve a progressive increase of the silverside stock and quality. The aim of this study was to evaluate the silverside population of the Cochicó shallow lake and, consequently, the management policies that are being implemented on this resource. Sampling was performed on a three-month basis, from April 2007 to March 2008, using gillnets and a trawl net. The relative abundance in number was estimated with gillnet capture. Catch per unit effort (CPUE) in weight was calculated considering the fishing night as the unit effort. The size structure of the dominant species was described and the proportional stock density index (PSD) was calculated. Odontesthes bonariensis was the dominant species, with a relative abundance of more than 92%. The mean CPUE was 201.6 kg/night. This value was higher than that found in previous years (19 to 120 kg/night) using the same methodology. The dominant size ranges were 25-27 and 29-31 cm total length (Lt). The PSD were 71% and 40% for sizes with potential recreational and commercial fishing harvest, respectively. The current quality and abundance of this fishing resource is essential for the Cochicó shallow lake and is the reason why it has emerged as one of the most prestigious silverside recreational fisheries locations in Argentina.Instituto de Limnología "Raúl A. Ringuelet