In this Globe and Mail article, yet another suggestion that exposure to in-river contaminants may be a factor in the survival of Fraser River salmon:
Among the endocrine disrupting ingredients identified in the Fraser were industrial chemicals, pesticides, compounds with a carbon-metal bond, pharmaceuticals and “several estrogen-like compounds,” the report says.
It states that data are insufficient to evaluate the impact of endocrine-disrupting compounds, but notes reports from First Nation fishermen that salmon are smaller on average, increasingly have blotchy skin and of one male sockeye that had ovaries, are cause for concern.
The idea that a virus may play a part in the unpredictable Fraser river sockeye returns is (month) old news, but this article in Scientific American is the first to mention chinook that I’ve seen. Perhaps the fate of the southern resident killer whales (who specialize on Fraser chinook in the summertime) is more connected than we thought to whatever marine factors govern the population dynamics of Fraser River sockeye?
“One of the most important findings of this study was the fact that salmon were already compromised before entering the river” on their journey home to spawn, she wrote. The scientists are currently studying juvenile salmon to see if the genomic signature is already present before they go out to the open ocean. Miller-Saunders also reports “there is some indication that the signature may be in Chinook and coho” salmon, too.