Millions of coastal dwellers rely on coral reef fisheries for food, income, and their personal and cultural identities. However, tropical reefs are threatened worldwide as corals are increasingly replaced by seaweeds (macroalgae), often accompanied by losses in fish resources. Overfishing and nutrient enrichment from sources on land are key drivers behind coral to seaweed transitions on shallow tropical reefs, but we have little understanding of the feedbacks and interrelations between fishing practices, coral reef livelihoods, and spatial patterns of coral and algal dominance. This is especially the case for small, local-scale lagoon fisheries where individual fishers harvest only for household and local community consumption. The adaptive capacity of these social-ecological systems is determined by factors such as available livelihood opportunities and access to resources, and the structure of networks through which information and resources are shared in communities. The project capitalized on recent advances in technology, inexpensive smartphones, and innovative ecological, social network, and modeling techniques to investigate these issues.

 Spatial patterns in fishing intensity and input of nutrients were explored in an island lagoon system. Although either factor alone could facilitate loss of coral and establishment of seaweeds, reefs may be particularly vulnerable if they experience both intense fishing and high levels of nutrient inputs from land. Patterns of fishing were delineated from household surveys, market analyses and interviews, and logs of fisher outings tracked by GPS on smartphones. Nutrient enrichment was assessed via analysis of environmental samples. The two factors were not correlated across the landscape, either among interconnected lagoons around an island, or among major habitats (fringing reef, mid lagoon, back reef) within a lagoon. These findings support spatially-explicit management involving control of nutrient inputs and strategic reductions in fishing pressure is possible by highlighting only specific areas to target. Fishery models helped refine further the particular types of fishes that could be targeted in management actions to prevent establishment of seaweeds.

One challenge in resource assessment in shallow reef systems is to obtain estimates of the cover of corals, seaweeds and other organisms on the ocean bottom at meaningful spatial scales. We developed and validated a computer vision approach to analyze bottom cover, based on computer analysis of many thousands of underwater camera images taken by divers. This tool enables rapid analysis of the amounts of coral and seaweeds covering the reef, over large spatial areas, and will greatly enhance the ability of resource managers to rapidly assess reef condition. The computer vision approach was combined with GPS-guided surveys of fish and sampling of nutrient enrichment to produce a synthetic picture of resource (fish) supply, level of nutrient enrichment, and type of cover (coral, seaweed) across the reef.

The COVID‐19 pandemic offered an unprecedented opportunity to explore the adaptive capacity and the role of livelihood diversification for households that engage in tropical local-scale fisheries. Socio-ecological analyses challenged several assumptions about livelihood diversification and adaptive capacity, suggesting that households who had diversified beyond fishing and worked in the tourism sector prior to the pandemic did so at the expense of decreased effectiveness in their fishing activities. The adaptive capacity gained by those who had taken up jobs prior to the pandemic in the lucrative tourism industry came at the cost of not being able to develop specialist fishing skills and ecological knowledge about the reefs, which was a critical limitation when they turned to fishing for food security during the pandemic.

Central to the project was a participatory training component that provided hands-on research experience for 7 graduate students, 16 undergraduate students, and 1 postdoctoral researcher. The focus at all three levels of training was to involve students directly in research activities, and to build skills and enhance teamwork. Undergraduate students conducted research in campus laboratories and at the field study site. The marine biology graduate students conducted field surveys, experiments and assays, working closely with senior personnel on the project. Two have completed Ph.D. degrees. Two anthropology graduate students carried out fieldwork on subjects pertaining to local marine management and circulation of marine based knowledge between local residents, NGOs and scientists, and completed M.A. degrees. Training for the postdoctoral researcher included guidance in executing collaborative and interdisciplinary field research. This has involved working closely with fishers and other stakeholders as well as the students involved in the project, and participation in numerous meetings involving interdisciplinary science.

Project findings have been disseminated to the scientific community via publications in the scientific literature, theses and dissertations, presentations at scientific meetings and workshops, as well as datasets made publically available via existing data-sharing infrastructures [Environmental Data Initiative (EDI), Biological and Chemical Oceanography Data Management Office (BCO-DMO)]. Local community groups, NGOs, stakeholders, and government agencies have been engaged in collaborative workshops and partnered research efforts to maximize information exchange and sharing of ideas and findings.

Last Modified: 10/23/2023
Modified by: Sally J Holbrook