Restored Oyster Reef Location and Design Affect Responses of Resident and Transient Fish, Crab, and Shellfish Species in Mobile Bay, Alabama

Abstract

Recent efforts to restore oyster reefs have resulted in the creation of many reefs with the explicit objective of benefiting local shellfish and finfish fisheries. We evaluated the community responses of the fish (transient and resident), crab, and shellfish species that colonized or utilized a series of restored high- and low-relief oyster reefs at three different locations within Mobile Bay, Alabama. Sites were chosen to represent different combinations of sediment type, proximity to established oyster reefs, water quality, and water movement patterns. The results showed substantial differences in reef community among the three sites and, compared with unstructured bottoms, increased abundance of several species of small demersal fishes and sessile invertebrates. Common mud crabs Panopeus herbstii and flatback mud crabs Eurypanopeus depressus were the only species to exhibit any consistent patterns in habitat use that could be directly attributed to reef height. The species composition of transient fishes did vary among treatments, but the total abundance on low-relief reefs and unstructured control areas was similar and often greater than that on high-relief reefs. There were significant two-way interactions between season, reef location, and reef design for most species abundances. These results suggest that the responses by resident and transient species to reef restoration were highly variable and that our ability to predict the community responses of resident and transient fishes to oyster reef restoration may be limited because of the interactions among location-specific biophysical characteristics.