Fur Seals

Seals making a comeback By the 1820s, Australian and New Zealand fur seals were almost completely wiped out by hunters. Today the two species are making a comeback at Cape Bridgewater, the only spot on the Australian mainland where the species’ breeding colonies can be found. Australian and New Zealand fur seal numbers are now estimated to be up to half of their population size prior to the sealing industry. “At that site there was only one pup in 1995. Now we’re seeing 100 of each species there,” Dr McIntosh said. While pleasing the increases are slow, Fur seal populations are increasing at just 2 per cent a year. Australian and New Zealand seal colonies have much in common but have distinct traits. “The Aussie fur seal is friendlier to other seals, but not to us – they quite like lying around and they’ll lie next to each other and over each other, whereas the New Zealand fur seals have a special rock and they lie on that rock and they don’t like anyone else to touch them,” Dr McIntosh said. “We think it’s the increased susceptibility to disturbance from land predators and humans that has prevented fur seals from establishing mainland breeding locations,” Dr McIntosh said. “I think one of the reasons the fur seals are coming back is we’re looking after them, we’re no longer hunting them, we’re protecting them, we’ve got Parks Victoria and Department of Environment, Land, Water and Planning managing them,” she said. Just to show how seals are able to adapt to their new environment, they are taking advantage of anything humans can provide. Oil rigs and artificial reefs are often given a bad rap for their environmental impact, but new research man-made structures are providing new feeding grounds for some Australian fur seals in Bass Strait. All but one of the fur seal breeding colonies occurred on islands between the Australian mainland and Tasmania, which has an average depth of 60 metres and is considered to be a region of low food availability for marine predators. Researchers tracked the foraging patterns of 36 Australian fur seals from Kanowna Island in Bass Strait, using GPS loggers and dive recorders. This revealed that some seals congregated around humanmade structures which act as artificial reefs attracting fish. Associate Professor Arnould of Deakin University said “We found that 72 per cent of the 26 seals we tracked spent time around the man-made structures, with pipelines and cable routes being the most frequented. “More than a third of animals foraged near more than one type of structure.” “Therefore, structures like oil and gas rigs and pipelines that occur on the relatively featureless sea floor could provide a valuable prey habitat and promote foraging success for the species,” he said. Associate Professor Arnould said man-made changes to natural habitats could often have negative effects on animals, but some species “can adapt to, and even benefit from, changes to their habitats”. “Indeed, man-made structures can provide a range of benefits for some species, from predator avoidance, thermoregulation, and breeding sites, to acting as important foraging areas,” he said.