Spat Collection and Growth to Commercial Size of the Tehuelche Scallop Aequipecten tehuelchus (D'Orb.) in the San Matias Gulf, Patagonia, Argentina

Studies on larval settlement and growth of the commercial scallop Aequipecten tehuelchus were carried out over a 2‐yr period in San Matias Gulf, Argentina. Gonadal index was used to indicate spawning and spat collectors were deployed when spawning began. Artificial spat collectors (mono‐filament bags filled with thin shrub branches) were placed at a depth of 25 m in two areas of the Gulf during two seasons (1989–1990 and 1991–1992). Maximum settlement occurred by mid‐February during the first season and by mid‐January in the second season. Larger numbers of spat were found in collectors placed near the sea bottom. After settlement, spat were removed and placed in cages for growout. Scallops reached the average commercial size (60 mm shell height) 16 mo later. Mortality rate during the entire period was 10%.