Effects of salinity, cold storage and enrichment on the calanoid copepod Gladioferens imparipes

Intensive culture techniques have been developed for the calanoid copepod G ladioferens imparipes. Despite reliable, long-term production of nauplii fr om these cultures, further improvements are required to maximise the number and nutritional content of nauplii available for feeding to larval fish. T he effects of salinity on copepod production and prolonged algal enrichment on nutritional content of nauplii is shown. Use of cold storage for accumu lating large numbers of nauplii and storing adults with minimum maintenance is evaluated. The size range of G. imparipes life history stages, particul arly early nauplii, is determined. Maximum copepod production was obtained in salinities of 18-27 parts per thousand. Fatty acid content of nauplii in creased with prolonged enrichment. Copepod survival was poor at 4 degreesC. At 8 degreesC, nauplius survival was 99% after 12 days and adult survival was 90% and 68% after 21 and 42 days, respectively. Early nauplii were 67 m um in width, similar to nauplii used to rear larvae with small gapes at fir st feeding. Implications of these results to the use of G. imparipes as foo d for fish larvae is discussed. (C) 2001 Elsevier Science B.V. All rights r eserved.