Declines in animal body sizes are widely reported and likely impact ecological interactions and ecosystem services (Nature.com)
Alaska salmon are getting smaller – that has implications for markets
Thursday, September 24, 2020, 18:00 (GMT + 9)
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.
Across Alaska, average salmon body size has gotten smaller (Image: courtesy Nature.com)
Researchers speculate that rising water temperatures in lakes and streams have prompted salmon to head out to sea far sooner than normal where they face more competition for food. 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.”
Body size declines are significant and nonlinear (Image: courtesy Nature.com)
The smaller salmon could affect short-term values – but that could be offset by a big decline in global harvests of sockeye, pinks and chums.
In the longer term, Tradex predicts that a shortage of wild salmon inventories will lead to pricing gains as buyers “lean towards the demand for smaller salmon.”
Author: Laine Welch | Fish Radio Programs
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