Abstract

This paper analyzes the response of the Bermuda coral reef fish assemblage to a fish pot ban that amounted to de facto protection of herbivorous parrotfishes (Scaridae) and surgeonfishes (Acanthuridae) after years of heavy fishing pressure. Hook-and-line fishing continued following the fish pot ban, and the differential impact of the two gear types on scarids and their predators created a ‘natural’ experiment that provides valuable insight into community recovery dynamics. We found that post-recruitment (> 5 cm FL) parrotfish biomass increased by a factor of 3.72 and abundance by a factor of 2.46. The asymptote in scarid biomass was attained in 5 - 6 years. The biomass of the dominant acanthurid increased by a factor of 3.5 and reached an asymptote in only 4 years. However, there was no increase in abundance of scarid recruits (< 5 cm FL) in this same time period, contrary to our expectation of observing a stock-recruitment relationship (SRR) in a demographically closed system such as Bermuda. As expected, biomass of most mesopredators remained low or decreased over the nine-year study period in those species susceptible to the ongoing hook-and-line fishing pressure. The changes in abundance of large predators e.g. black grouper (Mycteroperca bonaci), could not be properly assessed with the stationary census technique used due to their large home range and diver avoidance. Our study provides a rare insight into coral reef community recovery dynamics and demonstrates that when extirpated populations of herbivores are protected, the recovery of their biomass – and by inference their grazing function – can be rapid.

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