Sockeye salmon harvested in Bristol Bay were smaller than expected last year. The average weight was 4.5 pounds– the lowest weight on record, according to the Alaska Department of Fish and Game.
This summer, researchers are predicting that the average fish will be larger and heavier.
Curry Cunningham is an associate professor at the University of Alaska Fairbanks studying commercial fisheries.
“Sockeye put on between 90 to 95% of their growth out in the ocean,” Cunningham said. “And so the majority of the difference in size and weight of fish is whether or not they spent two winters out in the ocean or three winters.”
According to the Alaska Department of Fish and Game, 72% of last year’s sockeye salmon returning to Bristol Bay were the younger, smaller fish that spent two winters in the ocean.
Cunningham predicts that this season, more than half of the returning sockeye will have spent three winters at sea.
“Folks should expect across the board to see larger sockeye crossing their decks,” Cunningham said.
Ecologists aren’t sure why one sockeye salmon would spend two winters at sea, and another might spend three, but one factor could be genetics. Cunningham says there’s evidence to suggest that sockeye spend a similar amount of time in the ocean as their parents.
Another factor is how fast a sockeye is able to grow. The more time a fish spends in the ocean, the bigger it can grow, and Cunningham says larger fish tend to be more reproductively successful.
“At the same time, there's a cost to going to the ocean,” Cunningham said “There's a whole bunch of predators out there that can eat you.”
Sockeye that put on weight fast might be large enough to come home early, and avoid risking another year in the ocean where they might be eaten.
Bigger sockeye could mean more money per fish this summer for the commercial fleet. The size difference between fish that spend two or three winters in the ocean is big enough that you might be able to pick it out by eye.
“On average you can start to pick out what's your smaller [and] what's your larger fish,” Cunningham said “You may not be a hundred percent accurate, but we as humans are good at recognizing patterns.”
So if you’re out fishing this year and keeping an eye on size, you might be able to guess just how long a journey each sockeye salmon took to end up in your net.
