Macroscopic scale of gonadal stages and size at first maturity of Zygochlamys patagonica (King & Broderip, 1932) in management unit 2, SW Atlantic

CAMPODÓNICO, S.; LOMOWASKI, B.; LASTA, M.; MACCHI, G. J.

Halifax

Workshop; 16th International Pectinid Workshop; 2007

International Pectinid Workshop

One of the basic goals of fisheries management is to conserve sufficient reproductive potential of a stock to allow a sustainable exploitation supported by the knowledge of reproductive variables such as size at first maturity and extension of spawning period. The Patagonian scallop Zygochlamys patagonica inhabit the SE Pacificextending from Chiloe´ Island (42_S) to Cape Horn (55 -56° S), and the south-western Atlantic northwards to off the Rıo de la Plata estuary (35 -50°S) overlapping with the Shelf-break Frontal System at the 100 m isobath. The Patagonian scallop fishery is conducted since 1996 in the SW Atlantic. Due to the commercial importanceof this scallop, and in view of importance of increase the knowledge about reproductive characteristics of this species, the main objectives of this study were to: (a) describe a macroscopic scale of gonadal stages and (b) determine the size at first maturity. A macroscopic scale of gonadal stages was determined mainly based on color, external appearance and size of testes and ovaries. Samples were collected in early March 2001. Specimens (n = 247) were shucked and gonads were examined macroscopically for determination of sexual maturity. Macroscopic appearance observed was validated using a histological scale of maturity.