Abstract Summary
The widespread decline of coral reefs stems from a variety of local and global stressors affecting reef structure and function. Much attention has been paid to restoring stony corals as the architects of reef structure. However, in the Mesoamerican Reef coral cover has increased over the last decade, while low herbivory and excess nutrients have led to massive proliferation of macroalgae, which threatens to compromise continued coral growth, recruitment and coral restoration efforts. HRI’s Report Cards include recommended management actions - MPAs, fisheries regulations, pollution controls and restoration efforts. Since 2008 HRI has targeted herbivory as a key ecosystem function in need of restoration, given the doubling of fleshy macroalge measured over the last decade. Initially, our focus was on the protection of parrotfish. Belize was the first to protect parrotfish in 2009, followed by the Bay Islands, Honduras in 2010, Guatemala in 2015 and Quintana Roo, Mexico in 2018, completing protection all the MAR with the exception of coastal Honduras. Despite these efforts the proliferation of fleshy macroalgae continues to increase. In order to achieve a more balanced form of herbivory, we also need to increase populations of Diadema urchins and herbivorous crabs. Therefore, two pilot studies to translocate adult Caribbean king crab into no-take zones of MPAs were recently initiated in Belize, along with Fragments of Hope, and in Mexico, along with the Fisheries Institute. The hypothesized results include a reduction of fleshy macroalgae in the patches where crabs were translocated. A collaboration of NGO researchers and local fisher cooperatives could produce viable income generation venture with ecological benefits from reseeding some crabs onto the reef. Similarly we are planning similar experiments with Diadema in Honduras, in partnership with Tela Marine Station, Operation Wallacea and others. Finally, to remove ecologically ‘stuck’ macroalgal dominated communities, we are also testing the efficacy of human manual reduction of macroalgae in Mexico (with Centro Ecológico Akumal) and in Honduras (with CORAL). The ecological results of these pilot interventions, including time, costs and feasibility will be analyzed in terms of their potential for contributing to larger scale restoration of ecosystem structure and function.
