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Migration timing and distribution of juvenile salmon in Discovery Islands and Johnstone Strait



Discovery Islands
Photo: Dan McPhee (DFO)

Purse seines and Fisheries and Oceans Canada (DFO) trawl surveys have greatly increased the understanding of the migration and health of juvenile salmon within the Strait of Georgia, BC, especially for Sockeye Salmon. Surveys conducted in 2010-2012 revealed that Fraser River Sockeye Salmon do not enter the Discovery Islands area (a fish farming area) until the end of May, and that they are widely distributed throughout this area for at least part of June. To further assess risks associated with interactions between farmed and wild fish, information in the following key areas is needed:

  1. knowledge of migratory pathways of salmon and the duration of their residency in the vicinity of fish farms;
  2. knowledge of the prevalence of pathogens and diseases within wild and farmed populations; and
  3. knowledge of environmental and host conditions during the periods wild salmon reside in the vicinity of fish farms.

Additionally, more information is required to further understand when and for how long juvenile salmon are present in the vicinity of fish farms, as well as to describe migration timing of juvenile Fraser River Sockeye Salmon out of the Strait of Georgia. To gain this required information, sampling will be performed using a three-year trawl survey in the Strait of Georgia and a three-year purse seine combined with hydroacoustic surveys in Johnstone Strait.

This research will help explain how juvenile salmon utilize the Strait of Georgia, including the Discovery Islands area, with a focus on Fraser River Sockeye Salmon and to a lesser extent, Chinook Salmon. It will also provide the information required to fully assess the risks of disease transfer from salmon farms to the wild, understand the potential consequences of such transfers, and inform farm management policies.

This project supports the environmental performance and optimal fish health objectives of the Aquaculture Collaborative Research and Development Program (ACRDP), and pertains to the 2014-15 national ACRDP priorities of: 1) wild-farmed interactions; 2) environmental impacts - from aquaculture to the environment; 3) environmental impacts - from the environment to aquaculture; and 4) health management.

Program Name

Aquaculture Collaborative Research and Development Program (ACRDP)


2014 - 2016


Pacific: Strait of Georgia

Principal Investigator(s)

Stewart Johnson

Collaborative Partner(s)

Marine Harvest Canada Inc.

Grieg Seafood BC Ltd.

Cermaq Canada

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