On the imbalance between production and exploitation of marine fish assemblages: a case study from the Celtic Seas

Sustainable management of marine ecosystems has to take into account the conservation of many species that are not themselves targets of fishing, in addition to those that are commercially exploited. Dynamic size-spectrum models suggest that fishing which leads species to have similar ratios of yield to production (i.e. similar exploitation ratios) is not sufficient to protect those that are rare: these species need to experience lower exploitation ratios. Here, the status of the demersal fish assemblage in the Celtic Seas is examined from the perspective of yield and production, using survey data collected over the period 2012 to 2016, and incorporating both common and rare species. The results give no evidence that rarer species have lower exploitation ratios than common ones. This suggests that current management methods are not not operating in a way that conserves the fish assemblage as a whole.