Department of Fisheries and Oceans Statement on Sea Lice and Pacific Salmon Stocks

The Department of Fisheries and Oceans has undertaken research on sea lice on Pacific salmon stocks in the Broughton Archipelago as part of its Pink Salmon Action Plan.

The department conducted its research from the beginning of March 2003 until mid-June 2003. The sampling took place during that interval without interruption. Sampling was conducted in areas where there are fish farms and in areas where there are no fish farms. This was done in an attempt to better understand the role of fish farms as potential reservoirs for sea lice.

Preliminary indications from the monitoring program are that the vast majority of sea lice found on wild stocks are a species rarely found on salmon farms. Furthermore, the bulk of the sea lice were juveniles that have minimal impact on the host.

Sea lice are naturally occurring organisms that have parasitized salmon and other species of fish on the Pacific coast long before aquaculture operations were present. While sea lice can lead to mortalities in heavily infected fish, it is difficult to attribute the decline of Pink salmon returns in 2003 to this organism. Pink salmon populations are known for their high natural variability. Data from the Broughton Archipelago over the past 40 years reveal that similar low returns have occurred before salmon farms were present, and conversely, high returns have occurred long after farms were in operation.

Given the complexity and variability of natural systems, it is difficult and scientifically indefensible to draw conclusions about sea lice impacts or causal links after one season of study. For this reason, the results of the 2003 research will be examined and vetted by the Pacific Scientific Advice Review Committee (PSARC) on April 6th. A course of research will be confirmed following the meeting.

Additional information on DFO’s Pink Salmon Action Plan can be found at the following address:
http://www-sci.pac.dfo-mpo.gc.ca/mehsd/sea_lice/pink_salmon_e.htm