Growth, under laboratory conditions, of turbot, Scophthalmus maximus, from the R�a de Vigo (north-west Spain)

Abstract

In August 1983, 305 wild O-group turbot (Scophthalmus maximus L.) were captured at selected beaches of the Ria de Vigo, north-west Spain, for use in fattening trials. The fish were maintained in a flow-through system (0.015 m3 kg-1h-1) at ambient seawater temperatures (13° to 18°C) and salinities (32 to 35‰) for a period of 17 mo, and were fed a moist paste prepared in the laboratory. They were divided into two groups, the larger group having a mean individual weight at the start of experiments of 9.7 g, the smaller group having a mean individual weight of 5.7 g. Over the 17 mo period, the two groups grew to final mean wet weights of 1 905 and 1 123 g, respectively. Monthly food conversion indices, on a wet weight basis, varied between 2.1 and 5.9%. Survival during the 17 mo period varied between 90.0 and 93.1%. In a second experiment from November 1983 to February 1985, we tested the relationship between monthly growth rate and stocking density for two different groups of fish at 4 to 25 kg m-3 and at 6 to 75 kg m-3. Growth was essentially the same for both groups.