A three-year study to find out the viability of transferring adult walleye from Namakan Lake to Northwest Bay on Rainy Lake has found moving the fish to restock the population doesn’t work.
“As an agency involved in the study, I can say we certainly won’t be pursuing the transfer of walleye into the North Arm,” said Darryl McLeod, a biologist with the Ministry of Natural Resources in Fort Frances.
“Results suggest that stocking of adult fish into a large, open system like Rainy Lake is not a viable rehabilitative technique, due to the migration of the transplanted fish out of the North Arm and the higher rate of mortality on stocked fish,” he added.
The study, which involved 21 adult walleye implanted with radio- transmitters, took place from 1995-1998, with the results released earlier this month.
Seven were native control fish from the North Arm basin of Rainy Lake while the other 14 were from Namakan Lake.
An additional 216 transplanted fish and 144 control fish were tagged during the spring of 1994-96 and released at a known spawning location at the mouth of the Footprint River in Northwest Bay, making for the rest of the test subjects.
The purposes of the test were:
•to determine if the walleye remained in the North Arm;
•to find whether they used suitable spawning locations there;
•to determine the movements of transferred walleye from stocking location to potential spawning sites;
•to find out the susceptibility of transferred walleye to harvest from existing fisheries; and
•to compare the genetics of stocked fish to the native walleye.
During the study period, McLeod reported at least three transplanted fish left the basin while another seven (50 percent) died within the first two months.
None of the control fish died by natural causes.
The mean distance moved between contact points was significantly different between groups, with transplanted fish averaging 4.19 km compared to 2.57 km for the control ones.
And maximum distance moved between contact points was 43 km for transplanted fish compared to only 20.5 km for the contact fish.
Overall, said McLeod, the study indicated:
•transferred walleye did not all remain in the stocked basin of Rainy Lake, and adult transfers would not be an effective rehabilitative technique in any large, open system;
•most transferred adult walleye moved to suitable river and shoal spawning areas although actual spawning activity could not be confirmed;
•the original stocking location did not appear to influence spawning site selection for transferred walleye;
•walleye from Namakan Lake are genetically similar to walleye from the North Arm of Rainy Lake, and would provide a suitable donor or source stock of fish; and
•radio-telemetry provided a valuable tool for evaluating movement patterns and habitat selection for walleye in Rainy Lake.
McLeod said while the study showed transferring walleye isn’t the best way to restock this fishery, the North Arm is in good shape.
“The recovery of the fishery is underway,” he said, citing improvements in population abundance and spawning stock biomass (reported in 1997 index netting and spring trap net statistics) and alleged abundance in commercial gill nets.
And MNR actions since 1994-95 have resulted in the reduction of walleye harvests from both sport and commercial fishing.
While the study officially was conducted by the MNR, McLeod said many partners were involved along the way. “As an MNR representative, we certainly appreciate all the co-operation we received from the public,” he remarked.
Such groups included the North Western Ontario Tourism Association (particularly volunteer Geoff Gillon), the Fort Frances Sportsmen’s Club, Ontario Federation of Anglers and Hunters, and the Fort Frances Times (a sponsor of the Rainy Lake Ice Fishing Challenge during which walleye catches were monitored).
Others involved included Naicatchewenin First Nation, and many individual tourist camps, commercial fishermen, and pilots.
Fort Frances Times
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