The Chronicle-Journal/The Times News
Saturday, August 1, 1992

'True test' Faced by Triploid Trout

MNR approves stocking of four lakes with new, sexually sterile fish

About two years ago, a bold scheme was put to the public regarding the private stocking of sexually sterile 'triploid' trout into a handful of crown land lakes.

The aim of the project, which was initiated by a company called DAMSA, was to take a number of lakes barren of native fish and create a trophy trout fishery hatchery from sterilized triploid trout. The catch was that if the sterile trout took hold, these lakes would then become 'Total Control Access Lakes' - in other words, anglers would have to pay DAMSA a user fee to access and fish the lakes.

According to Lauri Parks, the president of DAMSA, the past 24 months have been a "very long haul". Parks says that since the first public consultation by DAMSA back in 1990, there have been complex legal problems to contend with, as well as questions regarding the private use of crown land and the possible affect of the triploids on native fish. With the majority of those hurdles now cleared, the project can now move to the next stage - introduction of the hatchery raised triploid trout into the wild.

"We have been given permission by the MNR to stock four lakes", says Parks, "and we will be putting in three different year classes of brook and rainbow trout into each one of them. One of the lakes is known to have winter kill problems and may need some additional help, but the others are prime trout water."

"I think this will be the true test of whether the program will go or not go", says Bob Hamilton, who has been overseeing the project on behalf of the Thunder Bay District MNR. "Now the thinking is over and the praying begins."

Up to this point, DAMSA has been raising its fish at a Kakabeka area hatchery, and they have been watching the growth of the fry closely. There are two different types of triploid brook trout at the hatchery - one group has been chemically treated with either estrogen or androgen to cause a sex reversal; the other group has been heat treated at the egg stage to cause sterility.

A third group of genetically normal Nipigon strain trout has also been kept at the hatchery to use as a control group. Each group of fish has been individually tagged and clipped to record growth patterns and to try and find out if and when sterile triploids start to outgrow their sexually normal brothers and sisters.

The term 'triploid' refers to the extra set of chromosomes (three instead of two) in the chemically treated trout. Preliminary studies have shown that triploids tend to grow slower than normal fish for the first two years, but quickly gain ground later on when sexually normal fish start putting more energy into sexual development.

Theoretically, sterile Nipigon strain brook trout - which have no sex organs - should grow to a radical trophy size in a very short period of time.

"Although there are internal changes, there are no external differences to the triploid trout at all", says Hamilton. "They look just like normal brook trout."

Once the fish go into the lakes, sanctuary status will be instituted by the MNR to ensure the fish get a chance to grow.

Then another three or four years of study will be undertaken to see how the trout respond to life in the lakes. If the fish do well, the DAMSA plan will go to stage three - development of the lakes for tourism.

"Plans are in the works for building lodges and cabins, but it will depend on the success of the fish whether we build or not", says Parks. "There should be no problem marketing this kind of trophy catch and release trout fishing in this area, as some of the local anglers already seek out this kind of angling in the states. Our market research has also shown us that there are an estimated 460,000 anglers in the mid-west states who are into this kind of fishing. These people put their fishing above just about anything else and are willing to pay for a quality experience. I think we could expect an excellent quality of angler using this kind of facility."

Hamilton says he is not as optimistic about the success of the program as Parks, but is fairly sure that at least one of the triploid strains will do well.

"One item of curiosity for me will be whether the triploid fish will grow out long and racy - like a pure Nipigon strain - or stay short and deep, like brook trout often do on inland lakes. That will be interesting."

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