Using Acoustic Telemetry Data to Define the Efficacy of Spatial Management for Coastal Sharks in the Great Barrier Reef Marine Park

Using acoustic telemetry data to define the efficacy of spatial management for coastal sharks in the Great Barrier Reef Marine Park

Danielle M. Knip^1*, Michelle R. Heupel², Colin A. Simpfendorfer¹

¹Fishing and Fisheries Research Centre, School of Earth and Environmental Sciences, James Cook University, Townsville, Queensland, 4811, Australia

²Australian Institute of Marine Science and James Cook University, Townsville, Queensland, 4811, Australia

*phone: +61 7 4781 3625, email: danielle.knip@my.jcu.edu.au

Spatial management tools, such as Marine Protected Areas (MPAs), are often considered ineffective for sheltering mobile species from exploitation. However, there is limited information regarding how mobile species use MPAs and the benefits protection zones may provide for these species. This research examined the presence and movement of sharks within coastal MPAs to define the efficacy of protection zones for sheltering mobile species from fishing pressure. An array of fifty-six acoustic receivers deployed in two protection zones within the Great Barrier Reef Marine Park monitored forty-three pigeye (Carcharhinus amboinensis) and thirty spottail (Carcharhinus sorrah) sharks fitted with acoustic transmitters from 2008 to 2010. Both species displayed long-term use of protection zones, with some individuals present in the study site for more than 600 days. The amount of time spent inside protection zones, the number of times borders were crossed and the area of protection zones used varied between individuals and species. The mean proportion of time pigeye and spottail sharks spent inside the protection zones was 22% and 32%, respectively, and the use of protection zones varied seasonally. Although pigeye sharks used large areas within the protection zones, they appeared to be more vulnerable to fishing pressure, with a capture rate of 21% by fishers compared to no captures of spottail sharks. The results of this research demonstrate that MPAs can provide shelter from fishing pressure for some sharks, but the movements and habitat use patterns of these species have significant implications for the design of protection zones.