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 The 1997 spawning run of Lake Superior Chinook salmon was similar to 1996, with very low numbers of returning mature fish, and below average numbers of eggs collected by the DNR. High incidence of BKD, Bacterial Kidney Disease was also found in the eggs. The Lake Superior Management Plan states that no BKD infected salmon will be stocked in the waters of Lake Superior. The plan also states; if spawning chinook salmon numbers fall to extremely low levels for three years in a row, the chinook salmon program should be reevaluated. |
At this time the MN DNR has approximately 40,000 disease free eggs on hand with plans to
rear all disease free eggs to the fingerling stage and stock them back into the French River
in the Spring of 1998. In a letter to the LSSA, Don Schreiner, MN DNR, stated "based on the low fall returns , it is
important that we immediately begin an evaluation of the chinook stocking program." Over the next two months the DNR will summarize their information and begin meetings with fishing groups around the state.
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 contaminant levels are down, and lake trout still aren't reproducing on spawning reefs, except in the middle of Lake Huron
Great Lakes fisheries scientists reject the theory that dioxins rather than nets and lamprey are the reason for the failure of lake trout
reproduction.
The dioxin hypothesis comes from OMNR's Mike Gilbertson, of the IJC. He
contends that dioxin in lake bottoms has been killing lake trout eggs and
just-hatched lake trout for at least 50 years.
Gilbertson, who just stepped down as chair of International Joint Commission, (IJC)'s Council of Great Lakes
Researchers, cites bottom samples from Lake Ontario indicating as long ago
as 1940 dioxin was as much as 2.5 times the lethal level for eggs and
embryos.
In lab tests, he says, lake trout eggs were killed when exposed to as
little as 35 parts of dioxin per trillion.
More on Lake Trout, visit the Great Lakes Fisheries Commission, or view the Dioxin Study in question, form Sea Grant News.
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That could be, says Michigan DNR fisheries research supervisor Dick
Schorfhaar, but it isn't why lake trout have failed to reproduce in Lakes
Huron and Michigan. Schorfhaar says the problem is too few lake trout
living long enough to spawn on suitable reefs.
Of the many studies conducted by former NBS biologist Mike Hansen, all
failed to show lack of reproduction on toxics.
Schorfhaar notes that dioxin levels are higher in Lake Ontario than in
northern Lakes Huron and Michigan, yet there is more lake trout
reproduction there than in the bigger upper lakes.
Overall, he points out, contaminant levels are down, and lake trout still
aren't reproducing on spawning reefs, except in the middle of Lake Huron.
"If we closed it down (got rid of all the nets and rods), we'd get
reproduction," Schorfhaar says confidently.
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