Drum net seiner in Johnstone Strait

Ecosystems 101: Beneath the waves

In warm water years, like El Niño years, the majority of the Fraser River sockeye salmon begins their migration to spawn via Johnstone Strait. While some people may argue that this means good things for people fishing in Canadian waters—because less sockeye will run through the trans-boundary waters of the Juan de Fuca—warmer waters bring a slough of other challenges for salmon.

In years with warmer ocean waters, salmon typically have less beneficial food to eat and more predators with whom to contend. Ocean currents carry Californian plankton rather than the more nutritious cold-water plankton that normally upwells on our coast. As majority plankton-eaters, sockeye depend on lots of nutritious phytoplankton and zooplankton to grow and survive.

Additionally, warm water predators that make it to B.C. waters place extra pressure on the sockeye. (The warm water currents also carry other critters too, like this sea turtle, that can be accidentally—and detrimentally—caught in the currents around Hawaii finding themselves stranded in B.C. or Alaskan waters.)

How can we have sustainable human food systems, if salmon don’t have sustainable ecosystems? As waters warm and as El Niños become stronger and more frequent as predicted as a result of climate change, industrial fishing practices will need to change too.

Featured image by Winky, via flickr