Using conventional and pop-up satellite transmitting tags to assess the horizontal movements and habitat use of thorny skate (Amblyraja radiata) in the Gulf of Maine

Abstract

Abstract Thorny skate (Amblyraja radiata) have experienced decreasing abundance and range contraction in the Gulf of Maine (GOM) in recent decades. To better understand the extent to which population structure, environmental conditions, and movement ecology may play a role in these disruptions, 128 “mark-report” pop-up satellite tags (mrPATs) and 2195 conventional tags were deployed from 2002 to 2019. Data obtained from 84 mrPATs and 43 conventional tag recaptures [127 individuals: 55 males, 72 females; 32–104 cm total length (TL)] revealed minimum linear horizontal movements of 0.4–46.8 km in all cardinal directions over periods 22–3435 d. There was no relationship between days at liberty, TL, sex, depth, reporting season, or tag type and minimum linear displacement, and no broad seasonal movements were evident. Skates were observed at depths 27–201 m and in water temperatures 2.5–12.5°C, with fluctuations in both depth and temperature evident by season. Given their restricted movements, thorny skate may represent a single stock/population with metapopulation-like structure in the GOM. The pervasiveness of sedentary behaviour may also place the species at risk of localized depletion and climate change but also demonstrates the potential efficacy of spatial closures for promoting population recovery.