Effects of rearing temperature on growth and survival of larval sablefish (Anoplopoma fimbria)

The effects of three different rearing temperatures (12, 15 and 18 degrees C) on growth and survival of sablefish larvae (Anoplopoma fimbria) were examined from 5days poststocking to weaned subjuveniles. First-feeding larvae were stocked into 960-L circular tanks at a density of 15larvae/L (n=3 per temperature treatment). Feeding, increases in light and water flow and other changes during the experiment were based on a degree-day (degrees Cday) schedule to adjust for time and temperature. The larvae were weaned on calendar day 41, 34 and 30 in the 12, 15 and 18 degrees C treatments respectively. Survival to weaning was greater at 15 than 12 or 18 degrees C. Calendar day and degree-day length and dry weight were greater in the 18 degrees C treatment. The larvae were weaned 7days earlier at 15 degrees C and 11 days earlier at 18 degrees C compared to larvae at 12 degrees C. Sablefish larvae can be reared at 15 degrees C with faster growth and good survival compared to 12 degrees C and at an approximately 17% reduction in cost and labour. Sablefish grew even faster but had higher mortality rates at 18 degrees C compared to 15 degrees C. Results from genotyping strongly suggest that there is a genetic basis for performing differentially at varying rearing temperatures and would also suggest that selection for faster growth and higher survival could be accomplished in a broodstock programme.