When a farmed fish escapes its pen, does the rest of the lake notice? Farmed rainbow trout in Lake Huron may outcompete their wild relatives when it comes to growth and feeding efficiency, Canadian scientists report. But they are left for dead when it comes to long-term survival.

The study by the Freshwater Institute Science Laboratory for the Department of Fisheries and Oceans Canada, focused on the differences of growth and feeding efficiencies between farmed and wild rainbow trout. It was published last year in the Journal of Great Lakes Research. A copy is here. 

Farmed rainbow trout possess slightly different traits than their wild counter parts, the study reports. Like most aquaculture creatures, they’ve been bred to grow as quickly and as large as possible. That produces bigger and more fish faster and more efficiently than catching wild fish one at a time.

At first the differences between the two differently raised fish may be hard to see.

Wild, or naturalized, rainbow trout have smaller and more streamlined bodies and may be better conditioned to find food in the lake when compared to the farmed rainbow trout, the study reported.

Martens and co-researcher Paul Blanchfield measured the differences.

Not only did their study find that farmed rainbow trout grow twice as large as wild rainbow trout, they also found that the farmed fish are 20 to 40 percent more efficient at turning fish food into fillets

[Source: Mollie Liskiewicz, Great Lakes Echo. Read the article]