Every year, the sockeye salmon return to spawn in the Fraser River in western Canada. Over ten million salmon are expected each year to enter the river from the ocean, swim upstream, and spawn. However, this year fewer than one million sockeye arrived at the appointed destination for laying their eggs, leaving scientists to wonder with great concern about the possible cause of the sudden and drastic drop in numbers. The Fraser River has been closed to both recreational and commercial fishing for the past three years, so it should be expected that the salmon population would have increased during that time. Instead, it has been decimated and no one seems to know why.

Various Possibilities

One possibility is that a marine parasite may have infected the sockeye population as they leave the river, swimming past commercial fish hatcheries where sea lice can be a problem. This could reduce the population drastically before the sockeye ever reach adulthood and return to the river to spawn.

Another possibility is that the rising temperature of the river may have weakened the fish, causing a massive die-off. This raises eyebrows in the conservative community who recognize that the documented temperature of the Fraser River has only risen by one degree Fahrenheit over the last half of a century. It seems unlikely that this gradual change would cause the sudden death of nine million fish.

Also up for consideration is the possibility that climate changes in the river and the ocean have reduced the Sockeye’s natural food supply, which also seems like a very gradual change causing a rather sudden shift in the salmon population.

Essentially, no one really knows why the Sockeye population is only one tenth what it is assumed it should be, in spite of efforts to protect the salmon and ensure their ongoing health and reproduction in the Fraser River. Hopefully the mystery will be solved before the Sockeye disappear altogether.