Fishing Impacts Reef Ecosystem
Australian researchers have found that fishing for predatory fish impacts the population of other reef fish species
While climate change, ocean acidification and spreading crown-of-thorns population are known threats to the Great Barrier Reef, researchers from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) at James Cook University have now found another impact on the reef's fish stocks: fishing.
Extensive surveys of the Great Barrier Reef have shown that removing predatory fish such as coral trout and snapper causes significant changes to the variety of reef fish in an area.
Study lead author April Boaden explains: 'A stable and healthy reef includes a high abundance and diversity of predatory fish and a relatively low number of herbivorous and small prey fish.
'Predatory fish are extremely important for maintaining a balanced ecosystem on the reef, yet predators such as coral trout, snapper and emperor fish remain the main target for both recreational and commercial fishers,' she says.
They team compared fish communities in designated marine reserves (green zones), recreational fishing areas (yellow zones) and sites that allowed both commercial and recreational fishing (blue zones). 'We found that the fish communities on reefs differed greatly according to the level of fishing that they were subject to,' Boaden says.
'Predator numbers were severely depleted in heavily fished areas, while smaller prey fish such as damselfish, and herbivores such as parrotfish, had increased greatly in number having been released from predation.'
The findings confirm the effectiveness of marine protected areas in preserving the numbers of predatory fish.
'Fishing impacts are something that we can manage fairly easily compared to other threats such as climate change and run-off pollution, which are threatening the Great Barrier Reef,' Ms Boaden added.