About the Atlas
About the Atlas
The Strait of Georgia, part of the Salish Sea which extends into both the U.S. and Canada, is one of the most biologically productive marine ecosystems in the world, supporting a variety of important fishing and aquaculture industries. Aquatic life in the strait takes advantage of the wide variety of marine habitats that are present, from the tidally-exposed shallow mud-flats at the mouth of the Fraser River to regions where depths are more than 400 m, and from the sheltered waters around the Gulf Islands and in the different mainland inlets to the open waters of the central strait. However, this variety also causes problems for scientific investigations and marine policy, because marine conditions in different locations in the strait may also differ greatly.
A recent issue of concern in this region is that Chinook, Coho, and Steelhead stocks, resident in the Salish Sea, have experienced tenfold declines in their survival during the marine phase of their lives, relative to conditions 30 years ago. Over the years 2014-2019 a large coordinated research program (the Salish Sea Marine Survival Project; SSMSP) was carried to better understand the reasons for these declines. Under so-called “bottom-up control” hypotheses about the factors that govern ecosystem operation, these changes would be linked to changes in marine conditions.
One problem is that the precise details of how and when marine conditions vary from place to place within the entire strait over the whole year (which requires sampling over many depths at high temporal resolution) have been mostly undescribed, largely because of the difficulties and cost of sustained data acquisition in the ocean. This is especially true in the central and northern strait, which are furthest from the various scientific and academic institutions that have traditionally studied this area. A coordinated program to sample different regions of the entire strait for the marine conditions important for fisheries, at monthly intervals, was last attempted in the late 1960s.