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2003 SEA LICE/PINK SALMON MARINE MONITORING PROGRAM FINDINGS - MAIN CONCLUSIONS OF THE STUDY

• The down stream migration of juvenile pink salmon was early in certain of the rivers, as predicted from water temperatures;
• Juvenile pink and chum salmon were found throughout the Broughton Archipelago and in Knight Inlet; those results do not provide confirmation for the existence of a main migration corridor in the Broughton;
• Two species of sea lice were found on juvenile pink and chum salmon - Caligus and Lepeophtheirus;
• Of the pink salmon examined, approximately 15% were infected with Caligus (a species rarely observed on farmed salmon) and only 9% were infected with Lepeophtheirus. The average number of lice per infected juvenile in the Broughton Archipelago ranged between ~1.4 and 1.7 ;
• Of the chum salmon examined, approximately 20% were infected with Caligus and 7% Lepeophtheirus. The average number of lice per infected fish in the Broughton Archipelago ranged between ~ 2.0 and 2.2;
• Caligus and Lepeophtheirus displayed different patterns of infection on juvenile pink and chum salmon -

  - Caligus infections were mainly (90%) juveniles (immotile grazers with a very low impact), and 10% sub-adults/adults (motile grazers with a higher impact);
  - Lepeophtheirus infections were more evenly divided between immotile (60%)and motile (40%) stages; and
  - All fish studied appeared to be in good health, in spite of any lice loads. Fish without lice were smaller than fish with lice.

• Some of the highest infection rates on wild salmon were in the waters where fish farms had been de-activated.

RESULTS OF THE PEER REVIEW PROCESS

The Pacific Scientific Advice Review Committee (PSARC) reviewed the two research papers resulting from the Marine Monitoring Program of 2003 in the Broughton Archipelago. PSARC is an open and transparent peer-review process of scientific research in support of fisheries/habitat/oceans managers in the Pacific egion. PSARC is designed to maintain rigour and impartiality. Participants at PSARC meetings include DFO, other federal departments and BC Provincial scientists, resource managers, external experts and stakeholders.

PSARC met on April 6, 2004 to assess the papers " Distribution and relative abundance of juvenile pink and chum salmon" and "Prevalence and infection rates of sea lice on juvenile salmon in the Broughton Archipelago area". About 50 participants attended the meeting and included government and non-government scientific experts in parasitology, salmon resource assessment and ecology. Participants from various stakeholder groups were also invited and attended.

The proceedings of PSARC meetings are publicly available from the PSARC Secretariat or on-line within about 1-2 months after the PSARC meeting. PSARC working papers, should they be accepted by the review committee, are also publicly available following suitable revisions as Research Documents.

PSARC conclusions

• Participants at the April 6th meeting agreed that the objectives of the PSARC working papers were largely met and both papers were accepted subject to revisions. It was noted that the study objectives were not designed to examine cause and effect relationships among sea lice infection rates, fish farm site location or farm management practices.
• The participants agreed with the authors of the working papers that indicated juvenile salmon were widely distributed throughout the Broughton area and appeared not to use a specific migratory corridor as postulated in 2002.
• No adverse effects of sea lice on juvenile salmon growth and condition factorwere observed for the period studied.
• The base-line data collected in the 2003 Marine Monitoring Program will be most useful in providing the foundation for more deductive-type studies in the future.
• Participants concluded that further research is required to confirm or reject the observations in 2003 that showed no impact of sea lice on juvenile salmon. If the impact of sea lice on juvenile salmon is found in future studies to significantly affect survival, then the source of sea lice and factors affecting sea lice prevalence and infection rates, including fish density and physical and chemical oceanographic steady-state variables, should be determined.

(Details of the discussions are provided in the PSARC meeting Proceedings/Advisory report)