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Salmon arrive early Mackenzie River fish research project continues into third year
Kassina Ryder
Northern News Services
Published Monday, September 23, 2013
NORTHWEST TERRITORIES
More salmon appeared in fishers' nets along the Mackenzie River earlier this summer than ever previously recorded, says a PhD student studying the fish.
Deline elder Alphonse Takazo displays the chum salmon he caught in Great Bear Lake in early September. He donated the fish to the Arctic Salmon project on Sept. 10. The fish will be used to further research about the prevalence of salmon in the Mackenzie River system. - photo courtesy of Karen Dunmall |
Karen Dunmall, a University of Manitoba student, has been researching salmon in the Mackenzie River and its tributaries since 2011.
"Chum salmon specifically have always been caught in the Northwest Territories, so the fact they're getting caught is not new, it's that they're getting caught in greater numbers and in more places," she said.
She said a salmon was caught near Deline at the end of August and another was found in Great Bear Lake the second week of September.
"I would never expect people to be catching salmon as far up as Great Bear Lake at the beginning of September."
Dunmall partners with Fisheries and Oceans Canada to perform the project, which relies on subsistence fishing to supply researchers with salmon through an exchange program. People who catch salmon can drop the entire fish or just its head to their local hunters and trappers association or other community office to receive either a $50 or $25 gift card for the Northern store.
"Without the salmon from communities, this project wouldn't happen," Dunmall said.
The fish are frozen and shipped to a Fisheries and Oceans research facility in Winnipeg.
Michelle Gruben, resource person for the Aklavik Hunters and Trappers Committee, said while the exchange program has existed for years, it was improved when Dunmall's project began.
Instead of waiting for gift cards to arrive from Inuvik, offices in communities collecting fish now have the cards on hand. Gruben said she hopes being able to give fishermen the cards directly will help prompt them to bring in fish more often.
In 2011, Dunmall said people brought in 226 salmon, which was considered unusually high. That number dropped to only 23 in 2012.
So far this year, six salmon have been brought in from fishing spots near Deline, Aklavik and Inuvik, but Dunmall said it's still early in the season.
Salmon are usually found in late September and into October.
Gruben said fishers have been reporting salmon in their nets more often over the past 10 years.
"It's unusual, but now it's becoming almost like a common thing," she said. "They never used to catch them, but now they're catching them on a regular basis this time of year."
Dunmall said the rise and fall of salmon numbers over the past few years could indicate a cycle, a belief shared by residents of settlements along the Mackenzie River.
"It is possible and that's something I've heard in many communities," she said. "The salmon are really high one year then it will be a few years before they're high again."
Chum salmon, the type of salmon typically found in the Mackenzie River, has a four- to five-year life cycle, Dunmall said.
Adults swim up the river in the fall and lay eggs, which overwinter in gravel on the river bottom before hatching in the spring. The young immediately make their way to the ocean after they hatch.
"If there is a good run of salmon one year, the juveniles won't be back again for four to five years," she said. "So that could perpetuate a cycle."
Pink salmon do the same, but have a shorter life cycle of about two years.
Dunmall said genetic testing is being done to determine whether salmon caught in the Mackenzie are returning to the place where they were born, or if they are a different population searching for new spawning sites.
Chum is the most prevalent species of salmon found in the territory, followed by pink salmon, but chinook, sockeye and coho salmon are also now being caught, Dunmall said.
Dunmall said another aspect of the research is determining how salmon eggs are able to endure Arctic winters and hatch.
The research team has been installing thermometers in the gravel where salmon would lay eggs.
Pipes are placed holding the thermometers, which sit about 46 centimetres below the gravel taking temperature readings the team can use to determine how eggs would develop.
Eggs must hatch at just the right time to allow young salmon to reach the ocean not too late in the fall.
"The timing is critical and the timing is related to temperature," Dunmall said.
Dunmall said climate change could be responsible for the warmer water that allows the eggs to survive and hatch.
"The increasing temperatures are likely allowing greater survival for the salmon," she said.
Chum salmon are now found throughout the Mackenzie River system, including the Liard River, the Slave River and in Great Slave Lake and Great Bear Lake.
Dunmall said the research will help solve unanswered questions about the salmon's new relationship with the Arctic.
"It's unusual for them to be caught in Great Bear Lake, for instance. It would seem to be unusual because chum salmon wouldn't normally use a lake for spawning," she said. "The fact that they have to go up the Bear River, it's off the beaten track. Are they spawning there or are they just lost?"
It will also help determine whether the changes that are helping the salmon are occurring predominantly in the ocean or in the Mackenzie.
"Something is going on that's either allowing the salmon to reach the Northwest Territories easier with less mortality, or the salmon that are spawning in the Northwest Territories are having greater survival," she said. "We don't know in which environment the changes are affecting the salmon the most. It's perhaps both."
Gruben said local fishers can help answer those questions by providing firsthand knowledge of the river.
"It's good that science and the community are working together," she said.
Dunmall said she hopes to continue her research for the next three years. Fisheries and Oceans Canada, the University of Manitoba, the NWT Cumulative Impact Monitoring Program through Aboriginal Affairs and Northern Development Canada, the Natural Sciences and Engineering Research Council of Canada, the Sahtu Renewable Resources Board and the Gwich'in Land Use Planning Board are providing funding for the project.
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