Recent Grad’s Research Helps State Plan Chinook Salmon Season

Wednesday, May 22 2013


MOSCOW, Idaho – Spring is here, Chinook salmon are swimming from the Pacific Ocean to Idaho hatcheries and rivers where they were born – and anglers are waiting for them. But how do state management agencies balance the need for adequate numbers of Chinook in the fisheries against anglers’ desire to stock their larders?

Thanks to Josh McCormick, a recent graduate of the University of Idaho College of Natural Resources, the Idaho Department of Fish and Game (IDFG) now has improved tools for managing Idaho’s Chinook salmon population. This is the second year IDFG has incorporated McCormick’s data into the Chinook season.

McCormick worked with the IDFG to improve sampling designs for creel surveys, in which “creel clerks” interview a sample of anglers to help the department estimate the numbers of Chinook being caught. As harvest numbers approach the quota – carefully determined before the beginning of the season – IDFG can decide when to close the Chinook season. 

Over two summers, McCormick spent about 60 days in the field using binoculars to observe anglers from before sunup to after sundown, recording the time they spent fishing and number of fish they caught. 

“It’s really expensive and time-consuming for natural resource planners to get this kind of data,” said McCormick, who now works for the Oregon Department of Fish and Wildlife. “It’s probably the kind of thing only a graduate student would do. It hasn’t been done a lot.”

Once McCormick had real numbers to work with, he ran simulations of various creel survey designs until he developed one that would provide the most accurate results, while taking into account the time and monetary constraints faced by Idaho’s fishery managers.

Thorough and accurate creel surveys are vital to making good wildlife-management decisions. Prior to McCormick’s work, the research on designing creel surveys focused on fish with different seasonal cycles than Chinook salmon – making them difficult to apply to Chinook.

If creel surveys underestimate the number of fish harvested, too few could return to the hatchery to spawn. This could have a profound impact on the species’ recovery and on the industry, which annually brings in upwards of $253 million to the state while supporting thousands of jobs. 

But if creel surveys overestimate the harvest, IDFG could shut down the season prematurely, denying anglers their opportunity to harvest salmon.

“The better design you have, the more likely you are to make correct inferences and decisions, and the better you can defend the decision you made,” McCormick said.

Michael Quist – College of Natural Resources associate professor, assistant leader of the Idaho Cooperative Fish and Wildlife Research Unit and McCormick’s adviser – said McCormick’s work serves as a guide to fisheries-management professionals in Idaho and around the world.

“It’s going to take some time to realize the full impact. But within the region, it has already programmatically changed how people are thinking about creel surveys and harvest estimates,” Quist said. “Josh’s research represents the very best the College of Natural Resources and the University of Idaho have to offer – and he’s not done yet.”

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Media Contact: Tara Roberts, University Communications, (208) 885-7725, troberts@uidaho.edu





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