Rainbow Smelt Weaning and the Effects of Temperature and Salinity on Juvenile Growth

Abstract

The rainbow smelt Osmerus mordax is a small anadromous fish that has potential as an aquaculture species because of its value as a premium baitfish. Three studies were conducted to establish a weaning protocol for larval rainbow smelt and to define the temperature and salinity ranges that support growth during their juvenile stages. In the first study, larvae were randomly assigned to one of two five-phase weaning protocols that lasted for 2 or 3 d per phase (designated P2 and P3, respectively) and a control group that was fed Artemia metanauplii throughout the study (n = 3 tanks per treatment). In the second study, weaned juveniles (approximately 67 d posthatch) were cultured in triplicate tanks at 16, 20, and 24°C and 15 g/L salinity. In the third study, weaned juveniles (approximately 180 d posthatch) were cultured in triplicate tanks at 0, 5, and 15 g/L salinity and at 17°C. Survival in the P2 (20.3%) and P3 (28.4%) treatment groups did not differ, but survival in the P2 group was lower than that in controls (46%). Survival did not differ in weaned juveniles raised at different salinities or temperatures, but growth declined at temperatures higher than 16°C. A high degree of cannibalism was noted in the postmetamorphosed juveniles, and procedures must be developed to minimize this problem in commercial operations.

Received June 28, 2011; accepted August 13, 2011

ACKNOWLEDGMENTS

We thank John Whalen (Harmon Brook Farm, Caanan, Maine) for broodstock and juvenile smelt, and Kristin Duclos, Daniel Merselis, and Mark Hagianis for assistance with fish care. This research was funded by the U.S. Department of Agriculture, Small Business Innovation Research and the New Hampshire Agricultural Experiment Station. This is scientific contribution 2477 from the New Hampshire Agricultural Experiment Station.