Lord Howe Island Shark Research Program

Testing deterrents to reduce shark bycatch and depredation and continuation of the deepwater acoustic receiver array 

Galapagos sharks (Carcharhinus galapagensis) occur in high abundance in the Lord Howe Marine Park (Commonwealth) and Lord Howe Island Marine Park (NSW) marine parks surrounding Lord Howe Island (LHI), and they are an important indicator species for marine park management. 

These sharks regularly interact with fishing activity, leading to shark bycatch and depredation (where sharks consume hooked fish before they can be retrieved). This is resulting in lost catch and fishing gear leading to conflict with local charter and recreational fishers and negative attitudes towards, and actions against, Galapagos sharks. 

However, other marine park user groups interact with Galapagos sharks in a positive way, including scuba divers and snorkellers. Supporting these positive interactions and finding approaches to reduce negative interactions between fishers and sharks is therefore critical to promote coexistence between humans and sharks in the marine parks and maintain important environmental, social and economic values. 

Research on Galapagos shark movement ecology and interactions with fishing vessels commenced in 2018 and has generated important baseline knowledge on their movement patterns, residency, depth range and overlap with fishing vessel activity (Mitchell et al., 2021; 2024). 

This research also generated a list of best-practice guidelines to help fishers minimise negative interactions with sharks, which was incorporated into a leaflet and poster for the LHI community and visitors. To further build on this previous work, long term monitoring of the population is valuable to learn more about the movements of the 30 individual sharks tagged in 2018, as they reach maturity, and to identify any changes in movement patterns over time linked to changing fishing dynamics or environmental patterns. 

The current project also tested two electrical and one magnetic shark deterrent to assess their effectiveness at reducing shark bycatch and depredation, using a two-phase approach. 

Continuing the deployment of the acoustic receiver array at LHI is recommended to further monitor this population and provide new insights into the movement ecology of adult Galapagos sharks, which is limited worldwide. Additionally, maintaining the array will provide vital ongoing benefits for investigating connectivity of marine megafauna across the Tasman Sea region. 

Further testing of shark deterrent devices to reduce fisher-shark interactions should be conducted to provide a technological solution to this issue and promote improved coexistence. Disseminating the results of the research and conducting further education activities with the LHI community is also highly recommended to raise awareness and foster further interest in Galapagos sharks and the marine parks surrounding LHI.