Short Presentation Australian Marine Sciences Association 2026 Conference

Colony-specific Trends in Australian Sea Lion Populations (139787)

Roger Kirkwood 1 , Dirk Holman 2 , Nathan Angelakis 1 , Sarah Catalano 1 , Kerstin Bilgmann 3 , Vanessa Morris 3 , Lynley Johnson 4 , Mel Stonnill 5 , Ryan Baring 6 , Clive McMahon 7 , Jacquomo Monk 8 , Mark Hindell 8 , Simon Goldsworthy 1
  1. SARDI Aquatic Sciences, West Beach, SA, Australia
  2. Sea Shepherd Australia, Williamstown, VIC, Australia
  3. School of Natural Sciences, Macquarie University, Macquarie Park, NSW, Australia
  4. PIRSA, Biosecurity, Glenside, SA, Australia
  5. Seal Bay Conservation Park, Department of Environment and Water, Kangaroo Island, SA, Australia
  6. College of Science and Engineering, Flinders University, Adelaide, SA, Australia
  7. IMOS Animal Tagging, SIMS, Mosman, NSW, Australia
  8. IMAS, University of Tasmania, Hobart, TAS, Australia

The endangered Australian sea lion (Neophoca cinerea) is Australia’s only endemic pinniped and the sole marine mammal listed on the Threatened Species Priority List. Following a population decline of more than 60% over four decades, recent management actions to reduce bycatch in demersal gillnet fisheries in South Australia have led to partial recoveries at some sites, but not in others. Several colonies, including two of the largest and most genetically distinct, continue to decline.

What could be driving these divergent trends? Emerging evidence points to nutritional stress as a key factor. Current pressures have been exacerbated by large-scale ecosystem disturbances, including a harmful algal bloom. The imminent threat of highly pathogenic avian influenza (H5N1) presents an additional species-wide risk, while climate-driven changes are reshaping both marine and terrestrial habitats.

This presentation will outline the species’ unique life history and highlight current research programs in South Australia, supported by state and federal agencies, and in collaboration with Traditional Owners. Effective recovery will require integrated, ecosystem-based approaches that address cumulative impacts from long-term drivers of decline and emerging risks.