The Australian sea lion, Neophoca cinerea, is an endangered species and its population is in decline. Identifying threats to the species’ recovery and exploring possible mitigation strategies is critical to the species’ survival. Hookworm infection is one of the greatest contributors to pup mortality in N. cinerea and has been listed as a priority research and management focus for the species.
This study compared the short-term (4 month) survival and the survival to weaning (18 months) in N. cinerea pups treated with a topical anti-parasiticide drug, ivermectin, compared to un-treated (control) pups sampled at Seal Bay Conservation Park, South Australia over two consecutive breeding seasons in 2019 and 2020/21. Kaplan-Meier survival estimates determined a significant difference in short-term survival between treated and control pups (n = 120, p = 0.024) in the 2020/2021 summer breeding season. However, neither short-term (n = 134, p = 0.79) or survival to weaning (n = 160, p = 0.51) were significantly different for treated and control pups during the lower mortality 2019 (winter) breeding season.
These results demonstrate that topical ivermectin could be an effective conservation tool to improve survival rates of N. cinerea pups during higher mortality summer breeding seasons.