In the Strait of Georgia, there was continued warming of the surface and bottom layers. These larger spring discharges are important because they affect the timing of the spring plankton bloom. This is noteworthy because coho salmon fishing in the Strait of Georgia supports one of the most important recreational fisheries in Canada. For example, in past years at the same time of this meeting, there would be a rather substantial fishery for juvenile coho salmon. We suspect that the ecosystem in the Strait of Georgia changed again when the physical indices changed about 1989-90.
Regimes are a new and important concept in the management of Pacific salmon.
A productivity regime can be considered to be the level of production within a particular ecosystem. While it is this level of production that is important for fish stocks, it is the change in regimes that is an important reference point for managers. It has been assumed in the past that the survival of salmon in the ocean is either without a long-term trend or that the highest, historic levels of production represent the upper limits of the possible marine production. There is growing acceptance of the impact on fishes and increasing evidence linking the climate trends in the tropical Pacific to the changes observed in the ocean, but there is no explanation of the mechanisms involved. Although the events cannot be controlled as we attempt to do for fishing effects, the effects of the regime shifts have profound impacts on regional economies.