Davis, B.

Since their introduction into the western Atlantic, lionfish (Pterois volitans) have become a major threat to the coral-reef ecosystems. Lionfish have proven to be formidable predators and it has been demonstrated that they have to potential to reduce recruitment of native fishes and even contribute to phase shifts. It is known that lionfish are capable of hunting and catching many species of native fishes, however little is known about the anti- predator responses of those prey fish. This study examined the antipredator responses of herbivorous ocean surgeonfish to lionfish. The ocean surgeonfish were visually exposed to a lionfish and their resulting behaviors were analyzed to determine if the fish exhibited an anti-predator response to an invasive predator. The naïve prey hypothesis predicts that prey will not react to predators if they do not share an evolutionary history with those predators, therefore it was predicted that juvenile ocean surgeonfish would not exhibit anti-predator behaviors in response to lionfish. The results of this study were inconclusive due to the absence of a positive control, but they indicate that ocean surgeonfish do not exhibit an anti-predator response to lionfish. If this study were to be successfully repeated with a positive control, the results may help to enhance our understanding of the ecological effects lionfish are having on the coral-reef ecosystem and will help us to mitigate those effects.

This student research was retrieved from Physis: Journal of Marine Science XV (Spring 2014)19: 21-29 from CIEE Bonaire.

Abstract

The effect of recreational SCUBA diving on coral reefs is likely secondary to many of the commonly cited stressors that threaten the long-term survival of coral reefs, such as rising temperatures. However, recreational SCUBA diving has had documented effects on various benthic organisms. Most research on the effect of SCUBA divers has focused on broken and abraded benthic organisms or the rate at which divers contact the benthos. We tested for differences in the structural complexity and benthic assemblage between pairs of heavily and lightly trafficked dive sites in Bonaire, a popular Carribbean diving destination. There was roughly 10 % less structural complexity in areas of heavy traffic. This is alarming given that the structural complexity of shallow reefs in Bonaire is substantially lower than in the 1970s. Different functional groups of benthic organisms were affected differentially by diving traffic. For instance, massive corals such as Orbicella annularis were 31 % less abundant at heavy than light diver traffic areas, while gorgonians and sponges had similar abundances at heavy and light diver traffic areas. Our results match those of previous studies on the resistance and resilience of tropical benthic reef organisms to physical disturbances that suggest that stony corals are more prone to physical damage than gorgonians and sponges. We provide a number of possible management strategies that could reduce the effects of recreational SCUBA divers on Bonaire and elsewhere, including education/intervention by dive guides and concentration of diving traffic away from areas of stony coral abundance.