Abstract

Reef degradation is caused by the integrative effects of natural disturbances (e.g. hurricanes) and anthropogenic stressors, including climate-change, fishing, pollution, and recreation. As water-based recreation increases so does the risk of anchor damage to coastal habitats, yet reef decline due to anchor damage is little understood and poorly documented. We used two approaches to assess the impact of anchor damage relative to other drivers of change on coral reefs in the British Virgin Islands. First, at one site that was monitored for 22 years, a one-time destructive anchoring event by a large vessel caused coral loss of a similar magnitude to chronic declines from other causes. Second, a synoptic survey of 25 sites that varied in how frequently boats anchored near reef revealed that anchoring explains a substantial fraction of the spatial variation in benthic community composition. In combination, these results indicate that anchor damage can have a substantial impact on coral reefs and habitat for fishes. In areas with frequent boat traffic, increased effort to mitigate this damage may thus be a worthwhile investment.

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