A Life After Research? First Release of Harp Seals (Pagophilus groenlandicus) After Temporary Captivity for Scientific Purposes

Three wild-caught female harp seals (Pagophilus groenlandicus) from the Greenland Sea stock were brought into temporary captivity in connection with a controlled validation study on energetics. The two pups and one adult were kept in two indoor and outdoor experimental facilities approved by the Norwegian Animal Research Authority. They were trained daily using operant conditioning to participate in experiments and husbandry and were regularly fed live fish. After 2.5 years, the harp seals were instrumented with satellite transmitters and released in the Barents Sea under a Norwegian Food Safety Authority permit. The tags transmitted for 45, 67, and 162 days for the juveniles and adult, respectively. The two juveniles remained in the Barents Sea east of the Svalbard Archipelago, while the adult female migrated to the Greenland Sea following a pattern consistent with that observed in wild harp seals from the same stock. They all performed regular deep dives (>100 m) and exhibited signs of foraging comparable to wild harp seals. Our results suggest that it is possible to conduct temporary captive studies with wild juvenile and adult harp seals. Study animals can be trained and subsequently released if they meet a set of criteria. This framework combines advantages of captive study design with traditional field methods and follows European ethical guidelines on animal experimentation with respect to the re-homing of experimentation animals.