Salmon are one of the types of fish that are called “anadromous.” This refers to their life cycle: they are born in fresh water, migrate down rivers into the ocean where they grow into adults, and then return to the fresh water to spawn (reproduce). One mystery is how the salmon “remember” the river of their birth, but these fish will predictably return to spawn in the place where they were born. Another, more recent, mystery is “WHERE HAVE ALL THE SALMON GONE ?”

Seven species of salmon live in the north Pacific and habitually travel up Canadian and U.S. rivers to spawn. Some sources cite evidence that these fish species have existed for up to 400 million years. Salmon have a delectable pink flesh and have been a favorite food fish for centuries. Major commercial salmon fisheries have operated on the west coast, and these fish are also highly prized by the “recreational” fishery. Throughout the last century it has been noted that the numbers of Pacific salmon have been declining. In recent decades this has been a great cause of concern and major efforts have been made to “support” and “protect” these fish stocks. Fish hatcheries have been used extensively in an effort to help increase the salmon populations. Another obstacle for the salmon has been man’s use of the rivers that they must travel. Pollution and dam-building seem to be the worst human-caused problems faced by the fish in the rivers. “Clean river” campaigns, the provision of “fish ladders” and the like have been part of major attempts to restore the river habitat of the salmon to a more hospitable state. These efforts appear to have been fairly successful.

Despite all “conservation and protection” efforts, the Pacific salmon are rapidly and “unexpectedly” disappearing. These fish are very accessible for scientific study during the time when they are in the rivers, and a fair amount is known about them. All the literature that I read on salmon stocks pointed to the same problem: “marine survival” is where they are failing. The condition of the river habitat is not killing them, they just “fail to return” from their time spent at sea. Great numbers of salmon “hatchlings” are set free, and the wild ones are counted on their way downstream. These numbers are used to predict how many “should” return...but they just are not coming back as predicted...why not?

Unfortunately, during their time at sea, salmon have a habit of travelling a fair distance away from the shore. That is where the ocean is hungriest. All of the other offshore fish stocks are disappearing due to the food shortage, and the salmon are affected in the same way. I cannot “prove” starvation in the salmon stocks because I have been unable to find weight-at-age data for any of them. (This I find a bit strange...considering the great amount of resources that have been spent on studying these particular fish...there are a lot of names for the different juvenile stages, but the adults seem just to be categorized as “small” and “large,” which is not enough information to make an assessment of their nutritional status.) Regardless, and this is only speculation on my part, but my theory on the disappearing Pacific salmon is that the phenomenon represents just one more part of a bigger and more serious picture: the STARVING MARINE ECOSYSTEM.

The disappearing Pacific salmon have been a source of great controversy on the west coast. Canada and the U.S. have practically had a “salmon war” as they fight over the remnants. Much has been written about the salmon, including a recent book “Salmon Without Rivers: A History of the Pacific Salmon Crisis” by Jim Lichatowich. I have not read it but have seen excerpts and favorable reviews. It seems to very well document the history of the Pacific salmon fishery, and the associated economics and politics. A better insight into the cause of their disappearance, however, would be entitled “Salmon Without Food.”

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Illustration - NOAA

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