A project undertaken at The University of the Sunshine Coast, and supervised by Kathy Townsend
Epaulette sharks, also known as walking sharks, are a unique group of small, bottom-dwelling sharks that inhabit the shallow coastal waters of northern Australia, New Guinea, and its satellite islands. Consisting of nine species, these sharks are unique in their ability to “walk” using their fins across reef flats. This group evolved approximately nine million years ago, making them the youngest group of sharks compared to the evolutionary history of sharks that spans over 450 million years. Interestingly, these sharks are currently described as having small yet distinct, non-overlapping ranges due to their poor dispersal abilities at all life stages. A recent review of the genus updated their distributions and descriptions, identifying non-overlapping ranges that are much smaller than previously considered. Given their bottom-dwelling lifestyle, populations are often fragmented by deep-water barriers, resulting in fine-scale population structuring, which is rare in shark species.
Figure 1.
This project aims to contribute to the first comprehensive assessment of the three species that are found exclusively in Papua New Guinea: Michael’s Walking Shark (H. michaeli), the Papuan Walking Shark (H. hallstromi), and the Hooded Walking Shark (H. strahani).
Currently all three species endemic to Papua New Guinea are considered vulnerable to extinction due to their limited ranges and shallow water habitats. Threats to these species include habitat loss due to coastal development, environmental degradation from climate change and marine pollution, and limited harvesting for subsistence fisheries and the marine ornamental trade. Despite their vulnerability, there are no specific protections in place for these sharks, and there is a lack of detailed information about their biology and ecology to support management decisions.
Figure 2.
Specifically, the goals of this project can be split into three main areas:
Population Genetics: Study the population genetic structure of walking sharks collected during surveys to reassess their distributions. This information will be used to identify any fine-scale population genetics that may be genetically important or highlight potential areas for hybridisation.
Reproductive Biology: Study trends in reproductive hormones using blood samples collected from the Conflict Islands over a 12-month period. This information will provide insights into the reproductive biology of Michael’s Walking Shark.
Educational Outreach: Support educational opportunities in elasmobranch science through conducting outreach with local communities and providing a paid intern/field assistant position for surveys. Additionally, we will work with local communities, conservation groups, and government bodies in PNG to raise awareness and build capacity for shark conservation.
With the upcoming review of the PNG National Plan of Action for Sharks and Rays 2021-2024, our research will provide tangible evidence to support management strategies. This project will not only enhance our scientific knowledge but also support the conservation of these endemic and vulnerable species in PNG.
This project is made possible by the support from the communities in Papua New Guinea that welcome us to do fieldwork, provincial and national government bodies that support this research, and our local partner, the Conflict Islands Conservation Initiative. This is a collaborative effort involving researchers from the University of the Sunshine Coast (UniSC), the University of Queensland (UQ), Conservation International, and the University of Tasmania (UTAS).
Fun Fact: Walking sharks are locally known by various names. In Milne Bay, some names include Kedekedewa, Gegeto, and Sigoita, which loosely translate to “dog shark” or “lazy shark.” Interestingly, the genus name Hemiscyllium is derived from the Latin “hemi,” meaning half, and the Latinized “scyllium” (from the Greek “skylion”), meaning dogfish.