For the first time, a colony of sea lions in Australia will be treated with a topical anti-parasiticide and then monitored long term for health and survival.
Led by Dr Rachael Gray, from the Sydney School of Veterinary Science, the research is investigating the effects of hookworm, environmental pollutants like heavy metals, and human-associated bacteria on mortality of sea lions in the first one-and-a-half years of their lives.
“Sea lion populations will continue to decline if we don’t do something to save these charismatic and iconic marine mammals,” Dr Gray said.
“Losing sea lions is not just an unacceptable loss of another Australian mammal, but has wider consequences for the ecosystem, as sea lions are top-end predators, so their numbers affect the numbers of many other species of animals in the ecosystem.”
Hookworm infects the intestines of 100 per cent of the Australian sea lion pups, so Dr Gray and her team are using a novel and minimally invasive treatment for hookworm and monitoring what effect it has on pup mortality.
“Many Australian sea lion pups die from intestinal hookworm infection, so we want to see what effect treating the hookworm has, not just on the mortality directly from hookworm, but also death from other causes, such as accidental injury from adults and pollution,” Dr Gray said.
“Our team has previously shown that an injectable form of hookworm treatment is effective, but we have recently piloted a topical treatment—which is easy to apply on the sea lion pup coat—and found that it is just as effective at treating hookworm.
“We’re looking at how eliminating hookworm can increase survival from other factors that are also killing sea lion pups; a system weakened by hookworm makes the sea lions more vulnerable to all sorts of other factors that can kill them.”