How can we mitigate shark depredation in Australian line fisheries?

Abstract

Shark depredation is a high-priority issue affecting many fisheries globally, including in Australia. It leads to higher fish mortality, socio-economic impacts on fishers, and loss of support for shark conservation. Building on 10 years of research in Australia, this national project conducted a comprehensive global review of all mitigation methods that have been tested around the world to reduce shark depredation. Methods were assessed through a semi-quantitative ranking process, using seven criteria (effectiveness, suitability across fishing sectors, cost to implement, impacts on target species, depredating sharks, non-target animals, and the environment). Ninety mitigation methods were identified and ranked and these were classified into four categories: 1) changes to fishing gear; 2) modifications to fishing methods; 3) fisheries management strategies; 4) shark deterrents. This generated a shortlist of the most promising methods for future testing in Australian line fisheries. Ten stakeholder workshops were run across WA, NT, QLD, and NSW to hear from local stakeholders about the impacts of shark depredation on their fishing, determine the key drivers influencing its occurrence, and provide practical feedback on the shortlisted methods. This has been further complemented by a national online survey. Overall, this project has created an important base for guiding future collaborative testing of suitable mitigation methods to reduce shark depredation.