Rockfish size and age: The crossroads of spatial protection, central place fisheries and indigenous rights

Indigenous people harvest wild species for food and cultural practice, fundamentally linking biodiversity conservation and indigenous rights. Rockfishes (Sebastes spp.) are culturally significant to indigenous people (or First Nations) of coastal British Columbia (BC), Canada, who regulate their harvest under traditional governance structures. First Nations elders, however, have observed a decline in the body sizes and abundance of rockfishes, which coincides with increased exploitation by non-indigenous fishers. Rockfishes are vulnerable to overexploitation because fecundity and offspring quality increase with maternal size or age, yet fisheries truncate size and age structure. During 2006, 2007 and 2013–2015, we worked with the Wuikinuxv, Nuxalk, Heiltsuk and Kitasoo/Xai’Xais First Nations of BC’s Central Coast, examining rockfish population characteristics at 282 of their fishing sites. We used hook-and-line gear to collect fishery independent data, and sampled landings from First Nations subsistence fishers. Spatial fishery closures served as experimental treatments. We also applied central place foraging theory to predict declines in size, age and abundance with increasing distance from recreational fishing lodges and other ports. Analyses used linear mixed models and controlled for environmental variables. Our results suggest that spatial closures for commercial and recreational fishers led to greater size and abundance of some, but not all rockfishes, possibly due to interspecific differences in the extent to which closures contain suitable habitat, effects of non-compliance, or other factors. Notably, Yelloweye Rockfish (Sebastes ruberrimus), a species key to indigenous diets, were 21% larger inside than outside spatial closures. Possibly reflecting cumulative fishery exploitation, however, old-aged Yelloweye Rockfish were rare. Fishery impacts on size and relative abundance decreased at sites that required longer travel times and greater fuel costs for recreational fishers to exploit, but only for the longest-lived species (size responses) and for long-lived species analysed in aggregate (abundance responses). Measures for protecting indigenous access to rockfishes include evaluation of habitat suitability and compliance within spatial closures, improved understanding of recreational fishery impacts, and treating old-age and large size structures as explicit management objectives. Our study contributes to a global effort to integrate indigenous cultural values with biological conservation.