Complexities and Uncertainties in Transitioning Small-Scale Coral Reef Fisheries

Abstract

International audienceCoral reef fisheries support the development of local and national economies and are the basis of important cultural practices and worldviews. Transitioning economies, human development, and environmental stress can harm this livelihood. Here we focus on a transitioning social-ecological system as a case study (Moorea, French Polynesia). We review fishing practices and three decades of effort and landing estimates with the broader goal of informing management. Fishery activities in Moorea are quite challenging to quantify because of the diversity of gears used, the lack of centralized access points or markets, the high participation rates of the population in the fishery, and the overlapping cultural and economic motivations to catch fish. Compounding this challenging diversity, we lack a basic understanding of the complex interplay between the cultural, subsistence, and commercial use of Moorea's reefs. In Moorea, we found an order of magnitude gap between estimates of fishery yield produced by catch monitoring methods (2 t km −2 ∼ year −1) and estimates produced using consumption or participatory socioeconomic consumer surveys (∼24 t km −2 year −1). Several lines of evidence suggest reef resources may be overexploited and stakeholders have a diversity of opinions as to whether trends in the stocks are a cause for concern. The reefs, however, remain ecologically resilient. The relative health of the reef is striking given the socioeconomic context. Moorea has a relatively high population density, a modern economic system linked into global flows of trade and travel, and the fishery has little remaining traditional or customary management. Other islands in the Pacific in similar contexts in Polynesia such as Hawaii, that continue to develop economically, may have small-scale fisheries that increasingly resemble Moorea. Therefore, understanding Moorea's reef fisheries may provide insight into their future

Associational refuge facilitates phase shifts to macroalgae in a coral reef ecosystem

“…, Leenhardt et al. ). Regardless of the mechanism involved, reductions in browsing pressure could provide a reinforcing feedback that promotes a macroalgal phase shift through limited top‐down control.…”

Coral Reef Resilience, Tipping Points and the Strength of Herbivory

“…An effect of intense fishing pressure is a reduction in body size of fishes due to size-selective harvesting52, and fishers in Moorea target both larger bodied species of herbivores as well as larger individuals within such key groups as parrotfishes53. By excluding herbivorous fishes above a sequential series of body sizes in our cage exclusion treatments, our intent was to mimic in a broad sense the effect of variation in fishing intensity on herbivory pressure.…”

“…Differences in the degree to which coral reef systems are close to tipping points will stem from variation in algal colonization and growth rates, the types and biomass of herbivores present and their ability to respond behaviorally and demographically to increased food supply following disturbances56. Humans can influence attributes of the herbivore assemblage both directly via fishing5355 and indirectly via destruction of nursery habitat for herbivorous fishes35. Herbivory alters the death rate of algae, and of course an herbivory threshold should also vary with factors that influence algal birth rates, such as the potential of the reef ecosystem to support rapid colonization and/or subsequent growth of fleshy algae.…”

Mapping social–ecological vulnerability to inform local decision making

“…Small‐scale coral reef fishing provides important livelihood and social benefits to local communities in Moorea but has shown signs of being unsustainable over the last decades (Leenhardt et al. ). We used Moorea as a case study for development of our approach because it has many features common to reef‐dependent communities on small island states throughout the tropics and because of the practicability of compiling the data necessary for the model.…”