Coastal sharks and rays in the Northeastern Atlantic: From an urgent call to collect more data to the declaration of a marine corridor

Abstract

Globally, elasmobranchs have suffered severe population declines and are, therefore, under an urgent necessity of protection, particularly along the Northeastern Atlantic realm. However, a lack of ecological (e.g., abundance) knowledge across this realm limits the implementation of adequate conservation and management actions. Here, we collected 4873 fish visual census count data (sightings at 403 sites, from 37 published studies) of sharks, rays, and skates, from coastal areas (< 40 m depth) throughout the Northeastern Atlantic, covering a latitudinal extent of ca. 60° and 9 ecoregions. We recorded a total of 14 elasmobranch species, from a total of 341 sightings, and only 4 % of the counts reported any sighting. There is a severe lack of ecological data (e.g. abundance) from most ecoregions, particularly those in the nearshore continental northern Atlantic and tropical ecoregions. Nevertheless, our results showed that species richness and total abundance of elasmobranchs was higher in the eastern Atlantic oceanic archipelagos, such as Azores, Webbnesia (Madeira, Selvagens, and the Canary Islands) and Cabo Verde, compared to the other ecoregions. Our study calls for prioritising conservation efforts in these areas, a stronghold for these vulnerable taxa, in addition to the establishment of systematic monitoring programs. Refining Marine Protected Areas (MPAs), including declaration of local 'Sharks Sanctuaries', along a marine corridor encompassing these archipelagos, seem pertinent in this sense. This proposal is backed by the evident diversity and abundance patterns in nearshore waters, strong social and economic support, and political willingness to align science and marine policy, under international (EU) governance schemes.