Our positive deviance research uses an approach for informing ocean sustainability and resilience that is focused on identifying and learning from outliers. Specifically, outliers that are doing well, despite difficult conditions. By their very nature, outliers deviate from expectations and consequently can provide novel insights on confronting complex problems where conventional solutions have failed.

We use this positive deviance analysis to uncover local actions and governance systems that work in the context of widespread failure and holds much promise in informing conservation.For example, in our 2016 Nature paper, we used a positive deviance approach to examine bright spots- reefs that should be degraded, but aren’t and see what we could learn about what they were doing differently.

Our bright spots were not simply comprised of remote areas with low fishing pressure. They include localities where human populations and use of ecosystem resources are high, providing novel insights into how communities have successfully confronted strong drivers of change.

Our pioneering work on bright spots has inspired a new rapidly growing field of study, that goes well beyond coral reefs, and has broad impacts in conservation science. Bright spots have since been used to identify locations of exceptional resilience on the Great Barrier Reef in Australia, jurisdictions with exceptional potential for shark conservation, climate change impacts on coral reefs, marine ecosystem conservation and restoration successes, fisheries policy successes in Canada, freshwater conservation successes, and applied to terrestrial environments such as lakes, wetlands, forests, agricultural landscapes, and even chimpanzee conservation. Bright spots are now a key part of the conservation science lexicon.

Our next project is examining reefs that are bright across multiple dimensions (sustainability, nutrition, and productivity) and exploring how they persist over time.  We will be conducting targeted fieldwork to uncover their enabling conditions and learn how these can provide lessons for building resilience in other locations.

A second major research theme involves innovations in quantifying human impacts on coral reef ecosystems. In particular, our work has transformed the way many scientists and managers view the causes of, and solutions to, reef overexploitation by mainstreaming research on how accessibility, particularly to markets, is a key driver of ecological conditions.

A major development was our conceptualisation and operationalisation of the human gravity metric, which captures the ‘gravitational pull’ of markets for every coral reef on the planet. Similar to gravity in physics, the concept of gravitational pull has also been used in economics to measure the potential for trade and migration between cities and countries, but had never been applied to environmental/conservation issues before.

Our team developed a ‘human gravity’ metric which has allowed us to conduct a series of global studies which reveal that the degree of market integration is often the strongest predictor of coral reef fish stocks, coral cover, and shark abundance. These results are hugely impactful because the conventional wisdom was that the major pressure on reefs is human population size, not market integration.

High market integration allows people to sell fish, rather than to fish for subsistence, thus the distinction between population and markets is crucial because the solutions to controlling overexploitation through market-based initiatives are very different and often underutilised.

Our gravity metric has been directly used in the analyses for over 80 coral reef ecology and conservation studies in the last five years.

Our team is at the vanguard of a global effort to rigorously quantify the effectiveness of marine conservation in order to better understand the contexts under which specific conservation strategies are most effective. We have developed an approach which uses statistical models from global-scale data to simulate counterfactual scenarios (i.e. what would have happened in the absence of conservation).

This model-based approach is necessary because in large-scale conservation the gold standard counterfactual methods for determining causality, randomised control trials and quasi-experimental design, are often logistically and ethically constrained (because large numbers of extremely marginalised people depend on natural resources). Our 2024 PNAS paper is the first to quantify what coral-reef conservation has achieved at a global scale.

By using a novel model-based counterfactual approach to simulate what would have happened in the absence of conservation efforts, we revealed that only ~10% of the global coral reef fish biomass is likely attributable to conservation. This study is ground-breaking because it quantifies the outcomes of marine conservation, rather than simply the inputs.

Most scientists and governments measure marine conservation progress by the amount of area conserved, which is an input, rather than an outcome. We used this counterfactual modelling approach in a series of recent papers in Science to quantify that reef shark abundances would likely be 6 times higher without human impacts  and to develop a depletion index which gauged the conservation status of reef sharks globally.

Additionally, we has used this approach to reveal that improving compliance in existing marine reserves would boost the probability of encountering top predators by 300% and nearly double fish stocks.

In collaboration with key project partners, including relevant management agencies, we are developing a series of sustainability reference points based on metrics measuring key aspects of fishery resources and associated ecological processes: (1) fish biomass, (2) productivity, (3) nutrition, and (4) size structure.

Building upon the findings of papers in Nature and Nature Communications, variation in time-series data about biomass recovery in no fishing reserves will be combined with data from remote areas with no fishing and data on local environmental conditions to generate downscaled estimates of unfished biomass (i.e. the amount of fish we would expect on a reef in the absence of fishing) on coral reefs.

These estimates are critical for determining bespoke fisheries reference points such as biomass at multispecies maximum sustainable yield (i.e. 50% of unfished biomass) or biomass representative of fishery collapse (~10% of unfished biomass) for each location.