Reuters reports that millions of sockeye salmon have disappeared mysteriously from Fraser River on Canada’s Pacific Coast where was once known as the world’s most fertile spawning ground for this kind of salmon.
There were fewer than 1 million of salmon have returned, dramatically drop from expected 10.6 million three years after the Canadian government has closed the river for commercial and recreational sockeye fishing.
Several theories have been put forward to try to explain the circumstance circumstance :
- Climate change may have reduced food supply for salmon in the ocean.
- The commercial fish farms that the young Fraser River salmon pass en route to the ocean may have infected them with sea lice, a marine parasite.
- The rising temperature of the river may have weakened the fish.
Though it’s not clear yet how these fish disappear, the decrease of salmon has effects on the environment around the river as it is also a part of the food chain.