Use of satellite tags to reveal the movements of spiny dogfish Squalus acanthias in the western North Atlantic Ocean

The use of popup satellite archival transmitting tags (PSAT) has helped to reveal horizontal and vertical movements of large, highly migratory fishes to assist in the management of their stocks. We tested the efficacy of a significantly smaller satellite tag, the X-tag, to track the movements of 3 spiny dogfish Squalus acanthias in the western North Atlantic Ocean. Tag retention rates for this study ranged between 65 and 189 d. The sharks occupied waters with temperatures ranging from 5.2 to 14.9°C and had estimated average horizontal speeds between 1.36 and 2.49 km h^-1. The sharks initially moved east into offshore waters after tagging in the Gulf of Maine and then into southern waters off the coast of New Jersey, USA. Diel depth patterns indicated that each shark was equally active during both day and night. Our results suggest that spiny dogfish are more mobile, both vertically and horizontally, than previously thought and that smaller PSATs can provide useful information on the movement patterns of a relatively small species of shark.