NEWS RELEASE CHIPPEWA OTTAWA RESOURCE AUTHORITY
*********************** SAULT STE. MARIE — In a major three-year study on Lake Huron, fish biologists are testing two hypotheses that could affect the way lake whitefish are managed.
Led by Fish Assessment Biologist Mark Ebener for the Chippewa Ottawa Resource Authority (CORA), participants have already accumulated a wealth of information and are looking forward to getting more.
"The study is important because the way we manage is on a stock basis," said Ebener.
The whitefish distribution study grant is made possible under the USFWS Great Lakes Restoration Act.
Participating with CORA in the study are the Michigan Department of Natural Resources, US Fish and Wildlife Service, Bruce Power, Chippewas of Nawash, Saugeen First Nation and the Ontario Ministry of Natural Resources.
Bruce Power later joined because of issues related to a restart of nuclear facility in Canadian waters of Huron's southern main basin.
Researchers hypothesize that most of the whitefish in central and southern Lake Huron are produced by whitefish that spawn in the Alpena and Fishing Islands regions.
"We believe that there is little spawning habitat south of Alpena and the Fishing Islands," Ebener said.
Researchers will test another hypothesis that lake whitefish stocks in northern Lake Huron — Cheboygan east to, and including, Manitoulin Island — tend to stray less than fish from the rest of the lake.
According to Ebener, there may be as many as 20 to 25 whitefish stocks in Lake Huron.
A stock is a group of fish that is spatially distinct from other groups, but not necessarily isolated from other groups during the non-spawning season.
His job is to identify what spawning stocks are contributing to the southern Lake Huron fishery.
Next, the researchers will identify any at-risk stocks.
"These are stocks that may be small and vulnerable to overfishing," said Ebener, explaining that these stocks would be reproductively-isolated groups of fish.
To make their determinations, the scientists are conducting a "mark-recapture" study of adult lake whitefish in Lake Huron.
That means captured lake whitefish will be tagged and released for later recapture by fishing.
Researchers are offering a reward for each tag recovered by fishers.
The recapture of the tagged whitefish is critical.
Researchers will use the information from these tags to determine the spatial distribution and movements of lake whitefish stocks in Lake Huron.
With the information, they determine the contribution of these stocks to commercial yields and use it to develop a distribution model that describes the relative magnitude of movement among management areas, including seasonal movement, for the population level modeling that determines total allowable catch (TAC).
In 2003, CORA tagged 3,238 lake whitefish in the Cedarville-Detour and Cheboygan areas.
In 2004, the groups collaborated to tag a total of 12,638 whitefish at eight sites in the main basin.
Only one whitefish was tagged at the South Bay mouth because rough seas destroyed the Ontario Ministry of Natural Resources (OMNR) trapnets.
With the information garnered from the tags recovered so far, the group assessed short-term and long-term mortality and tag loss at some sites in 2004.
CORA determined that the short-term and longer-term survival and tag loss in 2003 and 2004 at Cedarville-Detour and Cheboygan was zero.
Short-term survival ranged from 99 to 100 percent in 2003 and 2004, while longer-term survival ranged from 70 to 95 percent in both years.
The sex ratio of spawning fish at these two sites changed slightly from 2003 to 2004.
The first year females made up 42 percent of the whitefish tagged, and in 2004 made up 47 percent.
A $5 reward for the return of tagged whitefish is being offered.
Look for Ebener's work phone printed right on the tag, which will be red or yellow.
Ebener requests that fishermen phone him directly from the boat because researchers are attempting to build a GIS-based database.
If fishers can't call at the time of recapture, Ebener requests that they note the GPS coordinates, if available.
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