VANCOUVER - Researchers at Simon Fraser University say pesticides seem to be causing rainbow trout to lose their sense of smell.
They say that could harm the fish's ability to avoid predators, find mates and migrate back from sea, raising concerns that fewer trout -- members of the salmon family -- spawn each year.
The research, in collaboration with Environment Canada and Fisheries and Oceans Canada, is reported in the June issue of the journal "Environmental Science and Technology.''
Researchers tested the water quality in a 34-kilometre river in suburban Surrey, B.C., where they discovered at least 40 chemicals, mostly trace levels.
Using a mix of 10 abundant pesticides, they exposed trout to the mixture for several days before testing the fish's odour-sensing cells when exposed to the scent of a predator.
Researchers found that trout could not perceive changes in scent levels as well as unexposed trout.
