Herbivory and predatory pressures on artificial reefs in Bonaire, Dutch Caribbean
Artificial reefs are commonly used to increase habitat space for reef-dwelling organisms. Coral reefs in Bonaire, Dutch Caribbean, are degrading due to factors such as disease, bleaching events, and heavy storms, reducing habitat space for reef fish. Two different artificial reefs were deployed on the leeward side of Bonaire in 2011: one block and one branching structure. Studies found that both reefs supported fish communities but utilization of the reefs by fish was not studied. The current study examines utilization of branching and block-style artificial reefs for foraging and feeding activities by herbivores and predators to assess which reef structure provides more resources for fish. Herbivore grazing and predator stalking rates were calculated as well as herbivory and predation pressure at increasing distances away from the artificial reef. The branching artificial reef supported more herbivore and predator activity compared to the block reef, suggesting structural complexity increases important sheltering and feeding areas for reef fish. Predation and herbivory pressures showed no trend with increasing distance from the artificial reef while predation pressure decreased with increasing distances from the natural reef. This suggests that the artificial reef may act as a shelter between the reef crest and the surrounding sand and rubble area, thereby increasing foraging distances of fish coming from the reef crest. Not only resident, but transient individuals, were found to use the artificial reefs for feeding and sheltering, suggesting that artificial reefs do not need to create permanent habitats in order to be important habitat for reef fish.