Abstract: Contemporary global changes have put the capacity of future reefs to continue providing fish and fisheries production in jeopardy. Understanding future trends will require innovative and accessible strategies to measure potential fisheries production and to identify the impacts of global changes. In this talk, I will present a framework to quantify fish biomass production, aka ‘fish productivity’, from common underwater survey data and life-history traits. Applying this framework, I will then explore the trophic pathways that fuel reef fish productivity, as well as their susceptibility to coral loss and overfishing. I will use three case studies, which, in conjunct, provide evidence that: 1) plankton subsidies are important drivers of coral reef biomass production, even in reefs with low coral cover; 2) reef fish assemblages exposed to severe coral loss can undergo energetic shifts to a more productive, but potentially unsustainable, state; 3) overexploitation drives stronger declines in reef fish biomass than productivity, generating a compensatory production that may help to explain how sustained fisheries yields sometimes coincide with depleted biomass. By bridging the gap between common survey data and traditional fisheries production models, this framework can help to establish a new resource assessment paradigm on coral reefs.

Biography: Renato is an ecologist interested in understanding what makes some ecosystems more productive than others, with a focus on reefs and their fishes. Renato did his BSc in Biology and MSc in Ecology in Brazil and moved to JCU in 2016 to undertake his PhD under Dave Bellwood’s supervision. During his PhD he formalised an approach to quantify fish production from underwater count data, which he applied to tackle ecological and fisheries-related questions. In 2020 he started a post-doc at the Reef Function Hub and CoE CRS, investigating the contrasting effects of fishing on coral reef fish biomass and productivity.