| The objective of this research was to examine the feeding response and growth of triploid salmonids in comparison with diploids, using two innovative methods. The first method was designed to describe hierarchy formation within small groups of fish. Three fish of each ploidy were matched by weight or length, and placed in a v-shaped Plexi-glass trough and fed half the manufacturer's recommended ration, three times per day. The number of pellets eaten by each fish was counted and on this basis each fish was assigned a hierarchical rank.;The second method for describing hierarchy formation was used with larger groups of fish. Duplicate groups of 24 diploids, 24 triploids, or 12 of each ploidy were implanted with passively-integrated transponders (Pit-tags) and placed in circular tanks. Fish were fed half the manufacturer's recommended ration from a single point in the tank once per day. Every three weeks fish were fed a diet containing 1% radio-opaque glass beads, then anesthetized and radiographed two hours later. The following day their length and weight were measured. This procedure was repeated 14 times, over a 42-week period. (Abstract shortened by UMI.). |
