Much of the current literature is focused on the current and future effect of climate change and coral; bleaching on coral reefs. We study bleaching because we can see it happen. We ignore other less visible factors at our peril. It is hard to gauge the scale and consequences of fishing and to rank the relative importance of fishing impacts compared to bleaching, disease, pollution and acidification. This is what I, and my collaborators and students aim to do.

What is the scale of fishing on coral reefs?

I led a sustainability analysis of coral reef fisheries which demonstrated widespread overfishing across the world’s 49 coral reef island nations. At least 64% more fish and invertebrates are captured each year than can be sustained by these coral reefs. This is the only global analysis of the impact of coral reef fisheries.

Densely populated islands have unsustainable coral reef fisheries footprints.

There is a positive relationship between human population density per unit area of island coral reef ecological footprints The partial dashed line represents an ecological footprint = 1 for an MSY of 5 tonnes km-2yr-1.

What are the ecosystem consequences of overfishing?

Overfishing, particularly of predators, may have indirect consequences for food web structure, function and dynamics. I demonstrated how subsistence fisheries for food profoundly influence fish community structure and indirectly control the structure and function of Fijian coral reef ecosystems, using a 13-island gradient of fishing pressure. The removal of large predatory individuals results in compensatory increases in the numbers of smaller fishes [19,27] and order-of-magnitude increases in coral-feeding starfish [25,31,36]. These impacts, in turn, led to reduced diversity of algal grazing invertebrates [30] and widespread coral mortality shifting these island ecosystems from coral- to algal-dominance [25]. This work has been cited as some of the only analyses to have clearly demonstrated the cascading ecosystem-scale impacts of fishing on coral reefs.

These questions will be a key focus of my future research.

What is the relative importance of habitat loss and fishing?

What are the barriers to the successful implementation of MPAs?

What are the future trajectories of coral reef and coral reef fisheries?

What are the likely social and economic consequences of climate change and human population growth on the choices available to island people?