Acoustic telemetry and network analysis reveal seasonal spatial overlap between gadid species in a subarctic coastal marine protected area

Abstract

The Gilbert Bay MPA was established in Labrador, Canada to protect a resident population of Atlantic cod (Gadus morhua) and associated habitat. However, fisheries removals outside MPA boundaries have contributed to population decline and increases in potentially competing species may hinder recovery. Using acoustic telemetry and network analyses, we compared movements of Gilbert Bay cod (n = 23), conspecifics from offshore environments (offshore Atlantic cod, n = 19), and Greenland cod (Gadus ogac, n = 14) within and outside MPA boundaries from August 2014 – June 2017. Similar summer space use resulted in species overlap at seaward MPA boundaries and outside the MPA. In winter, Gilbert Bay and Greenland cod distributions overlapped within some MPA areas, and offshore Atlantic cod were absent. Some Gilbert Bay cod remained within the MPA year-round. Summer vulnerability to fisheries harvest outside MPA boundaries and winter overlap with competing Greenland cod within the MPA, may collectively challenge Gilbert Bay cod population recovery. Our study demonstrates the utility of acoustic telemetry and network analyses in evaluating animal movements for MPA management.