Prevalence of the parasitic copepod, Sarcotaces sp., infection in British Columbia rockfishes (Sebastes sp.) and implications for rockfish life-history

Marine fishes often suffer from parasitism, which can affect life-history traits like maturity and mortality. Rockfishes (Sebastes spp.) in the northeast Pacific are commonly parasitized by Sarcotaces copepods that form large cysts in muscle or body cavities. Baseline data on infection prevalence and effects are limited. We analyzed Sarcotaces infection in 23 rockfish species (including two thornyheads Sebastolobus), using over 37,000 individuals sampled in Fisheries and Oceans Canada groundfish surveys in British Columbia. Infection occurred throughout surveyed areas and depths, with rates up to 10%, highest in Pacific Ocean Perch, Silvergray, Rougheye/Blackspotted Complex, Yellowmouth, and Yelloweye rockfishes. Infection was linked to delayed maturation, particularly in males, which matured at lengths 22.3 mm larger (95% CrI: 5.5, 39.8). Immature fish were more likely to be infected than mature ones. Although speculative, Sarcotaces infection may act as a co-morbidity reducing survival. Body condition showed little association with infection, aside from a slight increase (~5%) in some species. To our knowledge, this study provides the first large-scale assessment of Sarcotaces infection and subsequent effect on rockfish life-history.