Development of Broodstock Diets for Atlantic Halibut

Project Summary

The overall objective of this project is to produce formulated feeds that will effectively replace the raw marine components currently used to feed Atlantic halibut broodstock. To be considered effective, the diet(s) will be accepted by the fish, maintain the health of the fish and fulfill the nutritional requirements for growth and reproduction. The intended result will be the production of viable gametes that enable efficient mass rearing of high quality juveniles.

The specific objectives are as follows:

1. To source high quality, traceable, pathogen free components that can be used to produce broodstock diets for Atlantic halibut.
2. To test two diets that will be used in experimental feed trials, one new off the shelf commercial diet and one experimental diet containing polychaete worms and crab meal to replace part of the fish-meal/fish-oil components.
3. To conduct a feed trial with the experimental diets alongside the control diet (wet fish, squid, vitamins) to mature Atlantic halibut for a period of 24 months.
4. To spawn eggs and milt from all ovulating/spermiating fish in the experimental groups for two seasons (Feb – May 2003, 2004) and investigate the effect of diet on egg production, egg quality and hatching rate.
5. To investigate effect of diet composition on egg composition.
6. To recommend a manufactured feed with a defined formulation for Atlantic halibut broodstock.

Progress to Date

1. The components for the experimental diet were successfully sourced and most had been received by the end of this reporting period. Some significant delays are being experienced due to importation restrictions on ingredients coming in from Canada due to the BSE crisis. The commercial marine finfish broodstock diet has been purchased from Inve US.
2. Proximate analyses have been performed on some of the ingredients received. A preliminary formulation has been designed based on these analyses and suppliers analyses. Each of the 38 fish in the broodstock population was weighed, measured, pit tagged, floy tagged and scanned using ultrasound. The latter was achieved with the help of Debbie Martin Robichaud of DFO, New Brunswick. The group has been divided into 3 groups of 3 replicate tanks each. The fish were divided as equally as possible with respect to sex and weight. The tanks were then assigned randomly to 3 treatments, 3 replicates per treatment. The population data is shown in the Table 1 at the end of the report.
3. The feed trial proper will start once the experimental diet has been formulated and manufactured. The equipment for diet preparation has been purchased. This will be used to produce sausage diets for the experimental and commercial diet.
4. Spawning is expected to take place between February and April 2004.