Abstract

The Catarina scallop Argopecten ventricosus is a highly valued resource. Although its hatchery spat production has already been reported, the effects of initial larval stocking density have never been reported for production purposes. This study evaluates A. ventricosus growth and survival in triplicate using three stocking densities: low (LD; 2 larvae mL(-1)), medium (MD; 4 larvae mL(-1)), and high (HD; 6 larvae mL(-1)). Three-day old larvae were reared in 18-L plastic carboy at 25.6 +/- 0.5 degrees C and fed with a microalgal blend of Isochrysis galbana and Chaetoceros calcitrans (1:1 cell number ratio) for 7 days, equivalent to 10 post-fertilization days (PFD). Higher specific growth rate was recorded at LD (15.8 +/- 0.2%) after 8 PFD of culture compared to MD (1.6 +/- 0.5%) and HD (4.1 +/- 1.8%) densities. The least time required for 60% of the larvae to reach the pediveliger stage was recorded at LD condition (10 PFD). Higher survival was recorded at HD (58.8 +/- 3.1%) at 8 PFD compared to MD (53.5 +/- 3.1%) and LD (43.9 +/- 3.0%). After 8 PFD, stocking density was highly related to larval growth and survival. To increase production and growth, and reduce the time required to reach pediveliger stage, stocking density should start with 6 larvae mL(-1) and be reduced to 2 larvae mL(-1) at 7 PFD.