My friend George Wuerthner forwarded an interesting article titled “Trouble at Sea: For salmon in the North Pacific, has the ocean reached its limit?” It was published in bioGraphic, an online publication I had not previously heard of. We’ve all read plenty about deteriorating ocean conditions and declining salmon stocks. An anomaly has been record returns of Bristol Bay sockeye. It turns out there is more than meets the eye in Bristol Bay, however. For example, there is an inverse relationship between overall run size and the size of individual fish which could lead to a variety of negative long term consequences.

While most salmon runs in North America are declining, last summer in Bristol Bay the number of sockeye salmon was a record high. The bad news is that the individual fish were the smallest ever. Shrinking fish is consistent with salmon returns all over North America. “The fish are growing more slowly at sea, and, in many cases, returning to spawn younger and smaller than ever before. In some places, the biggest, oldest salmon have completely disappeared.”

Smaller salmon impacts commercial fishermen, fish processors, sport anglers, and the ecosystems that rely on returning fish. Researchers point to deteriorating ocean conditions and hatchery management practices as important causal factors. Less food in the water and increased competition from hatchery fish is leading to smaller fish. Smaller fish are less productive commercially, potentially less resilient to catastrophic events, and have less reproductive potential. The article goes into detail on these and other issues, it’s well worth the read.