Estimation of sea lice infestation pressure from wild to farmed salmon populations in Klemtu, British Columbia, Canada

Principal Investigator: Thitiwan Patanasatienkul
Co-Investigator: Crawford Revie

Disease transmission between wild and farmed salmon populations is one of the key concerns around salmon farming, globally. A decrease in the number of wild salmon returning to certain rivers has been observed on the British Columbia (BC) coast, and sea lice have been implicated as a potential factor associated with these declines. Transmission dynamics from farmed to wild populations have been studied; however, transmission from wild to farmed populations on the BC coast has not yet been explored. Knowledge and understanding of trends and patterns of sea lice distribution around salmon farms will support development of more effective integrated management strategies and region-specific planning.

Simulation modelling has been used to explore the dynamics of sea lice populations in wild and farmed salmon populations, and to investigate different interventions to control sea lice on salmon farms. Details on infestation pressure around salmon farms are required to model sea lice levels on salmon farms, including sea lice abundance from surrounding farms, and wild salmon populations migrating through the area.

Investigation of these interactions will improve our knowledge of sea lice population dynamics and effects on both wild and farmed salmon populations. It will also provide us with a better understanding of sea lice exchanges between farmed and wild salmon populations, in both directions.

Hypotheses:

H1. Sea lice infestation levels on farmed salmon vary spatially and temporally.
H2. Sea lice infestation levels on farmed salmon are associated with infestation levels in wild salmon populations.
H3. Sea lice infestation levels on both salmon populations are associated with environmental factors (i.e. sea water temperature and salinity).

Objectives:

  1. To describe the infestation patterns (i.e. prevalence, abundance, and intensity) of sea lice on farmed salmon in the Klemtu area (H1).
  2. To assess the association between sea lice infestations on farmed and wild salmon populations in the Klemtu area (H2).
  3. To quantify the sea lice infestation pressure from wild to farmed salmon in Klemtu area (H2).
  4. To assess the impact of environmental factors (i.e. sea water temperature and salinity) on sea lice infestations on wild and farmed salmon in the Klemtu area (H3)