Photo credit: Fairbanks Daily News Miner
Since 2010 Alaska salmon have been getting smaller.
That conclusion is based on 60 years of measurements from 12.5 million salmon across Alaska, excluding pinks. A study by Nature Communications has compared average body lengths before 1990 and after 2010.
Chinook salmon have shown the most size reduction, averaging an eight percent decline, reductions in per fish egg production by16%, nutrient transport down 28%, a 21% decline in fisheries value and a 26% decline in meals for rural people.
That compared to size reductions of 3.3% in cohos, 2.4% in chum salmon and a 2.1% shrinkage in sockeyes.
At Bristol Bay, for example, the average sockeye weight this summer was roughly a pound less than the 20 year average of 5.7 pounds. Despite the huge catch, total poundage will be the least since 2014.
Researchers speculate that rising temperatures in lakes and streams have prompted salmon to head out to sea far sooner than normal. The drop in time spent in freshwater slows down fish maturity, increases time at sea and the salmon return at younger ages to spawn.
How might smaller fish affect fisheries and markets?
Smaller fish produce lower yields and that could mean adjustments for various salmon products. Tasha Cadence is with Tradex, a global seafood trading company based in Canada for over 30 years.
“Anyone who smokes their salmon has very specific recipe guidelines in order to produce a consistent product, therefore, if they typically use a 4-6lb sockeye, and the catch is heavy on the 2-4lb sockeye – they have to retool their whole operation/recipe. This could really hinder some long standing companies where their recipe has been used for multiple generations – and this consistency is part of their business model.”
Cadence says the smaller size also hurts processors who count on six ounce portions and good plate coverage from a 4-6 pound fish.
“Take that same portion off a 2 pound fish, now you have a thin 6” wide portion, a Chef’s cook time will change and the product will ultimately look way different. These changes in processing could directly affect companies who make prepackaged & portioned flavored retail items for freezers. If they begin using smaller sized fish it will mean changing their packaging and adjusting to a wider portion.”