Crabeater seals (Lobodon carcinophaga) might be one of the most abundant large mammals on the planet, but they rarely swim as far north as New Zealand. They are one of the characteristic animals of the pack ice zone that encircles Antarctica, hauling out on the floating ice to rest, breed, and to escape the attention of killer whales. Their name is a bit of a misnomer, as they specialise in feeding on shrimp-like krill, which they catch by straining mouthfuls of seawater through their bizarrely-cusped interlocking teeth.
Crabeater seals have been recorded from New Zealand shores on seven occasions, but the fact that most of these sightings have been adjacent to major centres (Wellington, Christchurch and Whanganui) suggests that more distant animals have been undetected, unrecognised, or unreported. The most recent reported sighting was at Kaikoura in 2011 – until now.
The Department of Conservation (DOC) received reports of an unusual seal ashore at Island Bay on 25 March. It returned to the sea, and was next seen the following day by the Avalon Bridge, up the Hutt River. It continued on up the river, with sightings opposite Taita Drive on 27 March, then at Manor Park over the weekend. It was inspected by DOC staff and a Wellington Zoo vet on 27 March who decided that although the animal was slightly emaciated, it was in no obvious sign of distress or external injury, and that no intervention was required.
The seal was reported dead on the afternoon of 31 March. It was lying on the edge of the Hutt River opposite Heretaunga Park, about 18 km from the sea. On delivery to Te Papa, the seal was determined to be a young male, just over 2 metres in length. It was in good condition externally, and so we will have to wait until it is prepared as a specimen before investigating possible causes of death.