State of the Physical, Biological and Selected Fishery Resources of Pacific Canadian Marine Ecosystems in 2019

Jennifer L. Boldt, Ania Javorski and Peter C. Chandler (Editors)

Abstract

Fisheries and Oceans Canada is responsible for the management and protection of marine resources on the Pacific coast of Canada. Oceanographically this area is a transition zone between coastal upwelling (California Current) and downwelling (Alaskan Coastal Current) regions. There is strong seasonality and considerable freshwater influence, and an added variability from coupling with events and conditions in the tropical and North Pacific Ocean. The region supports ecologically and economically important resident and migratory populations of invertebrates, groundfish, pelagic fishes, marine mammals and seabirds.

Since 1999 an annual State of the Pacific Ocean meeting has been held by DFO scientists in the Pacific Region to present the results of the most recent year’s monitoring in the context of previous observations and expected future conditions. The workshop to review ecosystem conditions in 2019 was held March 10-11, 2020 at the Vancouver Island Conference Centre, Nanaimo, BC. This technical report includes submissions based on presentations and posters given at the meeting.

Climate change continues to be a dominant pressure acting on NE Pacific marine ecosystems. Globally, land and ocean temperatures in 2019 were the second warmest on record and the occurrence of marine heatwaves (MHWs) in the NE Pacific is increasing. The upwelling-favourable winds along the west coast of Vancouver Island started at an average spring date with above average intensity, implying average to above average upwelling of nutrient-rich waters and, hence, productivity. In the spring and summer of 2019, surface nutrient concentrations along Line P were among the lowest on record. Anomalously warm ocean temperatures have resulted in changes to the phytoplankton community offshore and to the zooplankton community on the shelf. Changes at higher trophic levels have also been observed. For example, the returns and productivity of Fraser River Sockeye Salmon were the lowest on record, Smooth Pink Shrimp biomass on the west coast of Vancouver Island was among the lowest on record, and growth rates of Cassin’s auklet nestlings on Triangle Island (north of Vancouver Island) were below the long-term average. 

In the Strait of Georgia, the spring bloom timing was similar to the long-term average – which implies good feeding conditions for juvenile fish. Zooplankton biomass was above the long-term average with positive biomass anomalies of important zooplankton prey for juvenile salmon and forage fish. Forage fish have shown varying trends; for example, Pacific Herring biomass decreased in the Strait of Georgia and multiple sizes of Northern Anchovy continued to be present in survey catches. There has been a coast-wide decline in the returns of most Chinook, Sockeye, and Chum Salmon stocks in B.C., and declines of Coho Salmon stocks in southern B.C.; whereas, some Pink salmon stocks have had good returns.

A special session focused on physical and biological consequences of MHWs and climate change. There were five presentations given by DFO and ECCC scientists that examined the characteristics and occurrences of recent MHWs, defining MHWs, zooplankton responses to MHWs, and the effects of MHWs on seabirds and Pacific Salmon.