title: Effects of parasites from salmon farms on productivity of wild salmon.
abstract: The ecological risks of salmon aquaculture have motivated changes to management and policy designed to protect wild salmon populations and habitats in several countries. In Canada, much attention has focused on outbreaks of parasitic copepods, sea lice (Lepeophtheirus salmonis), on farmed and wild salmon in the Broughton Archipelago, British Columbia. Several recent studies have reached contradictory conclusions on whether the spread of lice from salmon farms affects the productivity of sympatric wild salmon populations. We analyzed recently available sea lice data on farms and spawner-recruit data for pink (Oncorhynchus gorbuscha) and coho (Oncorhynchus kisutch) salmon populations in the Broughton Archipelago and nearby regions where farms are not present. Our results show that sea lice abundance on farms is negatively associated with productivity of both pink and coho salmon in the Broughton Archipelago. These results reconcile the contradictory findings of previous studies and suggest that management and policy measures designed to protect wild salmon from sea lice should yield conservation and fishery benefits.
authors.affiliation: Department of Zoology, University of Otago, Dunedin, New Zealand. martin.krkosek@otago.ac.nz
authors.forename: Martin
authors.initials: M
authors.lastname: Krkosek
authors.forename: Brendan M
authors.initials: BM
authors.lastname: Connors
authors.forename: Alexandra
authors.initials: A
authors.lastname: Morton
authors.forename: Mark A
authors.initials: MA
authors.lastname: Lewis
authors.forename: Lawrence M
authors.initials: LM
authors.lastname: Dill
authors.forename: Ray
authors.initials: R
authors.lastname: Hilborn
mesh_terms: D000818:Animals; D033342:Copepoda / Q000502:physiology*; D005398:Fisheries; D012474:Salmon / Q000254:growth & development* / Q000469:parasitology*