Convergence of fish community structure between a newly deployed and an established artificial reef along a five-month trajectory

Abstract

Numbers of human-made reefs in the world’s oceans are increasing, yet questions remain about patterns and speed of fish colonization of these artificial reefs. Here, we tested 1) whether the fish community on a newly deployed artificial reef converged with the fish community on an adjacent, established artificial reef over time and 2) whether fish colonization of the new artificial reef occurred sequentially. To answer these questions, we simultaneously collected time-lapse videos of fishes colonizing a new (2 wks old) artificial reef and those inhabiting a nearby (438 m away) established (>20 yrs old) artificial reef. We found that fish community composition on the new artificial reef converged with the fish community composition on the established artificial reef over five months. Community development on the new reef followed a trajectory: schooling, planktivorous fishes initially colonized the reef in high numbers, whereas demersal fishes exhibited delayed colonization. These findings suggest that fishes may colonize human-made reefs along a specific trajectory of pelagic fishes followed by demersal fishes and that community convergence between reefs can occur over relatively short temporal scales given similar environmental conditions. When deploying additional structures, including human-engineered habitats, in the marine environment, our findings on fish colonization of artificial reefs are important to consider because they provide new insight into how artificial structures can be utilized to enhance particular fishes over different temporal scales.