In one of my Muskoka Outdoors News posts, I linked to a site that summarized the findings of a recent fish spawning research study. The study was looking at the effective spawning rates of hatchery raised fish. The findings suggest that the spawning rate of hatchery raised fish decreased significantly with each new generation of offspring. Also suggested by the study, was that the percentage of spawning, once released, is close to zero. Essentially, this is due to genetic issues that can occur with ‘inbreeding’.

CLICK HERE to visit the link I am referring to.

It seems to put a negative spin on the effective of hatcheries as effective management and restocking tools.

That was until I forwarded the link to the biologists at the Ontario Federation of Anglers and Hunters. They spearhead many hatchery projects in Ontario. The biologists encouraged me by reminding me that the primary purpose of hatchery raised fish is not to improve spawning rates in fish, but are used as “put-grow-take” fish resources. Spawning of these hatchery fish is not necessarily expected or needed.

Here is the OFAH biologist’s reply,

Without seeing the full report of the study it is hard to comment on its validity however I will provide some comments on fish culture in general as it relates to the study.

“The primary reason for poor recruitment in successive generations according to the article was due to genetic reasons. While someone in MNR Fish Culture could provide more details, the brood stock used for hatchery strains is diverse enough that there is little concern over inbreeding. The question is also however whether it is even important for successive generations need to spawn. A lot of the fish that are being stocked, especially rainbow, brook, and brown trout are being stocked as purely put-grow-take opportunities, no expectation that the fish will need to reproduce. In other species where the objective is to rehabilitate the population (eventual successful wild reproduction) as in Lake Simcoe whitefish, walleye and several areas for lake trout, wild collections are often done from the lake to eventually be stocked. Even with wild collections there are guidelines to be adhered to that ensure a wide genetic diversity.

I have very few concerns over the reproductive viability of our stocked fish. Typically there is more concern with habitat in the lake or river being stocked that eventually limits reproductive success. If the goal is to rehabilitate a fishery all aspects need to be addressed. If the reason the fish population deteriorated originally is because of the spawning shoal has been destroyed than regardless of how genetically fit the stocked fish are, reproductive output will still be zero because of limited habitat.”

Thanks for your input Mr. Holden. I really appreciate your quick response!

For interest’s sake, OFAH attached to their email the MNR’s best management practices for genetic considerations in their hatcheries. You can download the PDF here.