This month, as millions of sockeye salmon are leaving BC’s lakes and heading into the Fraser River, the largest sockeye salmon river in the world, researchers from the University of Northern British Columbia (UNBC) will be conducting an experiment that promises to help us understand how many will ultimately reach the sea.

The study will also help project the effect that environmental changes, such as a warmer climate, may already be having on the fish and their migration. This is the first time such testing has been done on BC’s famed sockeye salmon.

UNBC biology professor Mark Shrimpton is principal investigator on the project, which has been taking place this month at Chilco Lake west of the City of Williams Lake in BC’s Cariboo region. “The salmon need to undergo a biological change to successfully survive in the salt water of the ocean. Our initial research indicates that when they leave the lake, they have already undergone this change. A key enzyme in their gills that we use as a marker of the fish’s increased ability to survive the higher salinity in seawater is already at levels characteristic of a sea water fish,” says Dr. Shrimpton.

Dr. Shrimpton and his team will be holding the juvenile salmon they catch in water tanks of varying temperature and measuring how physiological and molecular biological indicators of development are affected by different temperature regimes over time. The team will also compare these measures to those found at other sockeye producing lakes in BC, such as Adams and Cultus.

“The salmon are only in this ‘window’ for a short period of time and warmer water shortens that time period even more. If the fish don’t make it to the sea while they’re biologically prepared, they will not survive the high salinity water of the ocean,” adds Dr. Shrimpton. “It’s not just warmer weather that affects them. There are models that predict the removal of trees near riverbanks, the building of dams, and the installation of some power plants also increase water temperature and can potentially have a negative impact on successful migration.”

The research is being carried out in coordination with Fisheries and Oceans Canada.