Talk provided during the Scottish Fisheries Co-ordination Centre Annual Biologist's Meeting, February 3rd and 4th 2016, Milton Birnam Hotel

1. Sea lice

2. Interactions group
Growing a sustainable salmon aquaculture sector and conserving
wild salmon and associated fisheries are key objectives for the
Scottish Government.
Examine the interactions between fisheries and aquaculture, and
explore possibilities for impact mitigation
• Sea lice
• Sweep netting
• Assess impact of sea lice on salmon fisheries

3. Sweep netting
• West coast fisheries trusts sea trout post-smolt monitoring.
• To identify regional trends for sea trout infestation with sea lice
• SFCC sampling protocol for sweep netting (2009)
• Data has continued to be collected from monitoring sites on the
west coast coordinated through RAFTS (2011-2015).

4. Sweep netting
• Sweep netting data from 2003-2009 has been analysed.*
*Middlemas et al. (2013) Fisheries Management and Ecology 20:68-74

5. Sweep netting (2011-2015)
• Standardised protocols
• Included sites further away from farms
• Sea lice classified to species and life stage
• Summary statistics
– Prevalance
– Intensity

6. Sweep netting
• Marine Scotland is currently examining the data collated by
RAFTS with regard to SSPO lice counts, SEPA data and distance
to farm.
• A small sample size, and site variation limits the analysis that can
be conducted so that only large scale patterns may be identified.
• Next steps

7. Impact of sea lice on salmon survival
• 2 projects started 2015
• SARF project (3 years)
Development of a network for determining spatial and temporal
variation in marine survival of Atlantic salmon and effects of anti-sea
lice agents
• ROAME- (10 years)
Assessing interactions and effects of sea lice on wild salmonid
populations
Modelling
Tracking
Impact
Mitigation

8. Impacts of sea lice
Approach outline
• Capture and tag migrating salmon smolts
• Treat one group with anti-sea lice compound
• Other group untreated
• Both groups released back to river
• Record numbers and condition of returning adult salmon in groups
• Estimate impact of anti-lice treatment on marine survival

9. Impacts of sea lice
• Similar studies have been conducted in Ireland and Norway
and these are on-going.
Requirement for Scottish study
• Results obtained elsewhere are not necessarily transferable
to Scottish conditions because many factors can potentially
influence the impact sea lice have on salmon populations.

10. The study was started in 2015
West coast (2 sites on Lochy) and
East coast (1 site on Conon) selected.
~2000 smolts captured at each site
1000 treated/ 1000 untreated.

11. Milestone Target date Title
1 31/05/2015 Complete tagging of smolts on Lochy and Conon systems.
Database information.
Complete
2 31/05/2016 Complete tagging of smolts on Lochy and Conon systems.
Database information.
3 31/05/2016 Complete construction of fish traps on the Lochy system
Out to tender
4 31/01/2017 Complete first year of capture of returning adults.
Database information
5 31/06/2017 Provide report on progress
6 31/01/2018 Complete second year of recapture of returning adults.
Database information
7 31/06/2018 Complete first analysis; organise discussion workshop
8 31/10/2018 Publish final report
Milestones for SARF project

12. • Initial data on return rates will help determine power available to
detect differences between sites in Scotland.
• Initial comparison of anti-lice treatment effect with data collected in
other countries.
• Not expected that the data collected during the project will be
sufficient to give a robust picture of the affect sea lice levels due to
aquaculture have on wild salmon.
Expected project outcomes

13. • The pilot will inform the design of
a network of treatment sites that
can detect the likely scale of
effects of sea lice in relation to
the overall marine mortality of
salmon.
Next steps