60 Years of Coral Reef Fish Ecology: Past, Present, Future

Abstract

Revisiting the past 60 yrs of studies of the ecology of fishes on coral reefs reveals successive decadal trends that highlight many lasting contributions relevant to fisheries biology, conservation biology, and ecology in general. The Bulletin of Marine Science was founded in 1951, about the same time SCUBA was first used to study reef fishes, so the 1950s was a decade of initial subtidal exploration by early pioneers. Detailed natural-history investigations of the use of space, food, and time by reef fishes developed in the 1960s, including studies based from undersea habitats late that decade. The 1970s saw the first comprehensive observational studies of reef-fish communities, as well as initial breakthroughs in behavioral ecology, especially regarding cleaning symbiosis, mating systems, and sex reversal. In community ecology, the conventional wisdom-that interspecific competition structured reef-fish assemblages via equilibrium dynamics and resource partitioning-was called into question by the lottery hypothesis, which posited that coexistence of ecologically similar species was fostered by nonequilibrial dynamics. The 1980s, in turn, were dominated by debate regarding the relative importance of larval supply vs post-settlement interactions in determining the local abundance and diversity of reef fishes. The recruitment limitation hypothesis asserted that larval settlement was so low that subsequent population dynamics were not only unpredictable, but also density-independent. Population and community studies during the 1990s thus focused largely on detecting demographic density dependence in reef-fish populations and identifying the mechanisms underlying this ultimate source of population regulation. From the 1980s to the present, studies of behavioral ecology and interactions between fishes and other reef organisms continued to flourish. Late in the 20th century, it became clear that coral reefs and their fish inhabitants were increasingly threatened, and conservation biology of reef fishes developed as a substantial new subdiscipline. The 2000s comprised the connectivity decade as new means of tracking patterns of larval dispersal developed. Knowledge of how larval dispersal connects local populations and/or results in self-recruitment that replenishes a local population is essential for understanding metapopulation dynamics and implementing effective fisheries management and conservation efforts. There is currently a major shift toward conservation biology among many reef-fish ecologists, including studies of the effects of and solutions for overfishing, habitat degradation, invasive species, ocean warming and acidification, and other human-caused environmental challenges. Marine reserves and protected areas are now well documented to be particularly effective at fostering both ecological resilience in general and fisheries sustainability on coral reefs. Future research must necessarily be conservation-based if there are to be any reasonably undisturbed reef-fish communities for coming generations of ecologists to study. I personally believe that those of us who have observed the demise of coral reefs first-hand have two major responsibilities: first, conduct basic or applied research indirectly or directly relevant to conservation of reef fishes, and second, speak out as both citizens and scientists to bear witness to these losses, which are largely unseen by the public, and assist managers and policymakers in saving our remaining reefs.