The comparative growth and survival of a naturalized and aquaculture strain of rainbow trout (Oncorhynchus mykiss) in laboratory and whole-ecosystem experiments
Martens, Matthew Thomas
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This thesis investigates the comparative growth and mortality of a naturalized (wild) and domestic (aquaculture) strain of rainbow trout (Oncorhynchus mykiss) common to Lake Huron. I first conducted a laboratory-based experiment, comparing the growth rates of the two strains. Under optimal and competition treatments, the domestic strain achieved a body weight ~2x that of wild conspecifics. Next, I conducted a replicated, whole-ecosystem study comparing the same strains. Both strains experienced equally low survival and the domestic strain segregated into a fast-growing group, (~3x growth relative to the wild strain), and a slow-growing group that had a lower growth rate than wild trout. A high growth rate for fast-growing domestic trout was achieved by a reliance on high energy prey as well as through low metabolic costs relative to wild strains. Together, these results demonstrate that aquaculture strains of rainbow trout have greater growth potential relative to wild conspecifics and may outcompete them in nature.