TITLE:
Use of Exercise and Structure during Rainbow Trout Rearing
AUTHORS:
Jill M. Voorhees, Nathan Huysman, Eric Krebs, Michael E. Barnes
KEYWORDS:
Routine, Velocity, Oncorhynchus mykiss, Salmonids, Environmental Enrichment
JOURNAL NAME:
Open Journal of Applied Sciences,
Vol.10 No.5,
May
29,
2020
ABSTRACT: A
combination of two forms of environmental enrichment (in-tank structure and
exercise) was evaluated during the hatchery rearing of juvenile rainbow trout Oncorhynchus
mykiss. The study used four treatments: 1) neither exercise nor structure, 2) exercise without
structure, 3) structure without exercise, and 4) both exercise and structure. Velocities in the unexercised tanks were a
constant 12.2 cm-s-1. Velocities in the exercised tanks alternated
weekly with one week at 12.2 cm-s-1 followed by a week at 30.5 cm-s-1.
Structural enrichment consisted of an array of vertically-suspended aluminum
angles. The use of either environmental enrichment technique significantly
improved final tank weight, gain, percent gain, and specific growth rate. Feed
conversion ratio was significantly and positively influenced only by structure,
but fish on the exercise routine were overfed. There were no significant
interactions between exercise and structure, indicating that each form of
environmental enrichment operates independently. The results of this study
indicate fish rearing performance can be improved with the addition of either
vertically-suspended aluminum angles or an exercise routine, but the
combination of the two techniques may not be needed to improve rainbow trout
growth.