Oral Presentation Australian Society for Fish Biology Conference 2024

Mapping Walking Sharks: New Distribution Insights for Site-Associated Species in Papua New Guinea (111450)

Jessica Blakeway 1 , Mark Erdmann 2 , Christine Dudgeon 3 4 , Julie Anne Waranaka 5 , Kathy Townsend 1
  1. Science Technology and Engineering, University of the Sunshine Coast, Hervey Bay, QLD, Australia
  2. Conservation International (Asia Pacific), Auckland, New Zealand
  3. The University of Queensland, Brisbane, QLD, Australia
  4. Science Technology and Engineering, The University of the Sunshine Coast, Moreton Bay, QLD, Australia
  5. The University of Papua New Guinea, Port Moresby, Papua New Guinea

One-third of chondrichthyans (sharks, rays, and chimeras) are listed as threatened with extinction on the IUCN Red List. Over 95% of sharks are assessed based on criterion A, relating to reductions in population size. However, only 3.1% of sharks (12 species) have been assessed using criterion B, which considers restricted geographic ranges and ongoing declines1. Walking sharks (Hemiscyllium spp.) fall under criterion B. These sharks exhibit strong site fidelity and habitat associations, making them more susceptible to localised threats such as habitat loss, harvest, and environmental degradation.

Hemiscyllium comprises nine species of small, benthic-dwelling sharks endemic to northern Australia, the island of New Guinea, and its satellite islands. Of these, five species are classed as threatened, including three species endemic to Papua New Guinea (PNG)2. Currently, there are no local or national species-specific protections for walking sharks in PNG, and limited information exists to inform management, with distributions particularly unclear3.

Through a series of in-situ surveys, we aim to reassess the distributional limits of walking sharks in PNG while collecting essential baseline biological and ecological data to benefit future management. Here, we present our preliminary results, updating the range limits of two species from PNG (Hemiscyllium michaeli and Hemiscyllium hallstromi).

  1. 1. Dulvy, N. K., Pacoureau, N., Rigby, C. L., Pollom, R. A., Jabado, R. W., Ebert, D. A., Finucci, B., Pollock, C. M., Cheok, J., Derrick, D. H., Herman, K. B., Sherman, C. S., VanderWright, W. J., Lawson, J. M., Walls, R. H. L., Carlson, J. K., Charvet, P., Bineesh, K. K., Fernando, D., … Simpfendorfer, C. A. (2021). Overfishing drives over one-third of all sharks and rays toward a global extinction crisis. Current Biology, 31(21), 4773–4787.
  2. 2. VanderWright, W. J., Dudgeon, C. L., Erdmann, M. v, Sianipar, A., & Dulvy, N. K. (2022). Extinction Risk and the Small Population Paradigm in the Micro-Endemic Radiation of Epaulette Sharks. Imperiled: The Encyclopedia of Conservation, 752–762.
  3. 3. VanderWright, W. J., Allen, G. R., Derrick, D., Dudgeon, C. L., Erdmann, M. v, & Sianipar, A. (2021). Hemiscyllium michaeli (amended version of 2020 assessment). In The IUCN Red List of Threatened Species.