Friday, October 1, 2010

Lake trout spawning project a success

Ontario Ministry of Natural Resources crews left here yesterday after gathering 100,000 or so lake trout eggs. The eggs will be raised in the OMNR fish hatchery in Dorion, near Thunder Bay, and the fingerlings released back to Red Lake in 18 months time.
I believe this is the eighth year of this project which is intended to ensure Red Lake continues to have a viable lake trout population while researchers determine why the fish cannot successfully regenerate in Pipestone Bay.
It still isn't clear why they cannot reproduce there. So far we've learned that the fish are healthy, the water is pristine but there seems something about the sediment that kills the trout eggs. It was thought that manganese, a naturally occuring metal that is present in the very rocks where they spawn, might be the culprit but that is now not so certain.
Even if it was the problem the scientists are stumped why it didn't affect the trout eggs in the past. There is also some evidence that the problem might be slowly going away. Many of the fish being caught for the spawning project are relatively young, perhaps 8-12 years old. The poor spawning record of the trout seems to have begun in the 1980s. The presence of the young fish means trout are successfully spawning somewhere. But the lake trout population continues to be just a fraction of what it was 20 years ago.
Fishing regulations require all anglers to immediately release lake trout on Red Lake. They must also use lures with single, barbless hooks when targetting trout. Barbed and treble hooks are OK when fishing for other species.
Although the bulk of the OMNR spawning crew left camp on Thursday a small group stayed behind to catch more trout whose eggs will be reared in incubation boxes that are placed in various locations around Red Lake. The eggs inside the boxes will hatch this winter and the hatchlings can swim free out into the lake. It is hoped they will imprint on the shoals where the boxes were placed and come back there to spawn when they become mature. In this way the trout could be encouraged to spawn somewhere other than Pipestone Bay which is the only location they are unsuccessful.

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