Quantifying shark depredation in a recreational fishery in the Ningaloo Marine Park and Exmouth Gulf, Western Australia

Shark depredation, where sharks consume hooked fish before they can be retrieved, occurs frequently in recreational fisheries and can lead to higher mortality rates for target species, injuries to sharks, and negative impacts on the fishing experience. A study conducted in the Ningaloo Marine Park and Exmouth Gulf, Western Australia, found that shark depredation occurred on 38.7% of fishing trips from west coast boat ramps and 41.9% of trips from Exmouth Gulf boat ramps between July 2015 and May 2016. The study surveyed 248 boats at west coast ramps and 155 at Exmouth Gulf, quantifying depredation rates for demersal fishing (13.7%) and trolling (11.8%) in the west coast, compared to 11.5% and 7.2%, respectively, in the Exmouth Gulf. Spatial variation was observed, with higher depredation rates in areas of greater fishing pressure, suggesting a possible behavioral association in depredating sharks. Depth, number of nearby boats, and survey period influenced depredation rates in the west coast, while fishing pressure and latitude affected depredation in the Exmouth Gulf. This is the first quantitative assessment of shark depredation in an Australian recreational fishery, offering insights to help fishers and managers mitigate its impact.

Mitchell, J., McLean, D., Collin, S., Taylor, S., Jackson, G., Fisher, R., & Langlois, T. (2018). Quantifying shark depredation in a recreational fishery in the Ningaloo Marine Park and Exmouth Gulf, Western Australia. Marine Ecology Progress Series, 587, 141–157. https://doi.org/10.3354/meps12412