Indirect effects of fishing on non-target fishes across Australia’s Great Barrier Reef

Overfishing is common in marine systems across the globe, with rates increasing worldwide since the 1970s. This overfishing can have ecological consequences for marine fishes and their habitat including those across coral reefs. While fishing effects are well studied for commercially targeted species, there is less information on effects of fishing on ecologically important non-target species and associated flow on effects. Therefore, in this thesis we present a study assessing indirect effects of fishing and marine protected areas on non-target species across the world’s largest coral reef, Australia’s Great Barrier Reef. First, background on fishing methods, their effects on non-target species, and consequences for coral reef habitat are presented to understand the existing knowledge and address future directions for the conservation of these species. Then, using remotely operated vehicles we extend the existing knowledge by exploring these relationships across larger spatial scales than previous methods. Results confirmed differences between zones, with increased abundances of non-target fishes in non-fishing compared to fishing zones. Though, these relationships were nuanced and highlight the importance of considering other drivers including habitat cover and in water visibility. Finally, we suggest future directions and emphasize the use of ROVs as a valued tool for marine assessments.