Pink Salmon Action Plan

Statement on DFO Aquaculture Science

10/24/2006

Over the past 30 years, DFO has been involved in a wide range of aquaculture research programs. The objective of this research has been to provide a sound science and technology base for the management of marine resources and for innovations within the aquaculture industry.

During this time, DFO scientists have pioneered many areas of research and have been recognized for significant findings in the areas of fish health, biotechnology, genetics and marine ecosystems interactions. A major focus of DFO research has been to determine factors that pose a risk to the health of wild salmon, as demonstrated by the recent publications noted below.

Focus on Science, Wild Pacific Salmon, and Salmon Aquaculture

In June 2005, Canada's Policy for Conservation of Wild Pacific Salmon was announced. This policy is a strong commitment to the conservation of wild salmon and their habitats, recognizing this goal as DFO's first priority in resource management decisions related to Pacific salmon. To achieve this, DFO will consider the ecosystem of salmon as a whole: the living resources, the aquatic habitats and interactions among species, the effects of ocean and climate variation, and the impact of development and human activities. Within this context, the development of salmon aquaculture is one of numerous human activities which influence Pacific salmon.

In the issue concerning salmon farms, sea lice, and wild salmon in the Broughton Archipelago, DFO has undertaken extensive research, both in the field and the laboratory. The department also welcomes independent scientific research into the potential impacts of sea lice and the interactions of wild and farmed salmon. Some recent papers have, however, generated media reports stating that sea lice produced from salmon farms are a major cause of losses in wild salmon populations.

DFO has obtained comprehensive data from the Broughton Archipelago over four years of sampling juvenile salmon and sea lice infections and fish health, plus monitoring annual returns of adult salmon. See the backgrounder entitled, "2003 - 2005 Results" that compares sea lice levels on pink and chum salmon in the Broughton Archipelago and Knight Inlet during this time period. In 2006, DFO’s sampling shows that sea lice infections on wild salmon in the Broughton Archipelago are the lowest since observations began in 2002.

Laboratory studies have assessed the impact of sea lice infection and survival of small pink and chum salmon. Comparison of juvenile pink and chum salmon infected and non-infected with sea lice in 2003 and 2004 indicated no significant differences in health or size of the sampled fish.

DFO research does not support the close association between salmon farms, sea lice, and loss of wild salmon reported by others.

DFO findings are outlined in the Pacific Region Pink Salmon Action Plan Bulletins.

In recent years, wild pink salmon stocks in the Broughton Archipelago have been strong despite claims to the contrary.  While 2006 returns of adult pink salmon this year were low, this was the case all along the Pacific coast including Alaska where no aquaculture exists, and not limited to the Broughton Archipelago.

Pink salmon returns fluctuate historically, and there have been significant fluctuations in adult pink salmon returns since 1953, long before salmon farms were introduced to the area in 1987. A recent publication by Beamish et al. (#1 below), reports that farmed and wild salmon can coexist successfully in B.C. 

Recent publications related to fish health and salmon aquaculture:

1.     Reference: Beamish, R.J., S. Jones, C. Neville, R. Sweeting, G. Karreman, S. Saksida, and E. Gordon. 2006. Exceptional marine survival of pink salmon that entered the marine environment in 2003 suggests that farmed Atlantic salmon and Pacific salmon can coexist successfully in a marine ecosystem on the Pacific coast of Canada. ICES J. Mar. Sci. 63: 1326-1337.)

2.     Brooks, K. M. and D. J. Stucchi. (2006). The effects of water temperature, salinity and currents on the survival and distribution of the infective copepodid stage of sea lice (Lepeophtheirus salmonis) originating on Atlantic salmon farms in the Broughton Archipelago of British Columbia, Canada (Brooks, 2005) - A response to the rebuttal of Krkosek et al. (2005a). Rev. Fish. Sci. 14: 13-23.

3. Foreman, M.G.G., D.J. Stucchi, Y. Zhang, and A.M. Baptista. 2006. Estuarine and tidal currents in the Broughton Archipelago. Atmosphere-Ocean, 44(1): 47-63.

4. Jones, S.R.M., G. Prosperi-Porta, E. Kim, P. Callow, and N.B. Hargreaves. 2006a. The occurrence of Lepeophtheirus salmonis and Caligus clemensi (Copepoda: Caligidae) on Three-spine Stickleback Gasterosteus aculeatus in coastal British Columbia. J. Parasitol. 92: 473-480.

5. Jones, S., E. Kim, and S. Dawe. 2006b. Experimental infections with Lepeophtheirus salmonis (Kroyer) on threespine sticklebacks, Gasterosteus aculeatus L., and juvenile Pacific salmon, Oncorhynchus spp. J. Fish Diseases 29: 489-495.

6. Jones, S.R.M., Prosperi-Porta, G. & Dawe, S. A new parvicapsulid (Myxosporea) species in adult pink salmon, Oncorhynchus gorbuscha from the Quinsam River, British Columbia, Canada. Journal of Parasitology (in press).

7. Marty, G.D., G.A. Karreman and S. Jones. (2006) Prevalence and seasonality of new pathogens in juvenile salmonids from inner coastal British Columbia, Canada. 47th Western Fish Disease Workshop, Victoria, BC (abstract).

DFO Science-based Management 

DFO relies on sound scientific knowledge to make management decisions and regulations. Hasty decisions or actions based on inconsistent results place natural resources at risk and/or incorrectly impact people’s lives.
In the biological sciences, the development of new scientific knowledge is seldom straight forward or fast. There are many unknowns, interactions, and natural environmental variations that contribute to differing findings between research projects.

Given alternative research outcomes, it is imperative that more research and scientific analysis be undertaken to help us fully understand the ecological effects. Only through replication of studies, prediction and verification of outcomes, and observation can we build confidence in new results and knowledge.
Research concerning salmon farms, sea lice, and wild salmon is an example of this dilemma in natural science.

The wide ranging estimates of juvenile salmon mortality that were recently published (i.e., "Farm-origin sea lice induced 9-95% mortality in several sympatric wild juvenile pink and chum salmon populations.") are of limited use in the development of effective policy and management plans.  If sea lice do account for some juvenile mortality, is it incremental to other natural sources and does it equate directly to losses of spawning adults? The latter can not be assumed as there are many factors during later life phases that will influence the final number of adult salmon that return to spawn.

Differences in scientific perspectives may be confusing to the public but are certainly not unusual during the development of new knowledge. It can be expected and is healthy for the development of a sound scientific knowledge.

DFO will continue to evaluate all sources of information in this issue to ensure healthy wild salmon populations while developing a management plan for a sustainable aquaculture industry.

Ultimately, it is the number of adult wild salmon reproducing that must be sustained.