July 17, 2019 — Oyster reef restoration provides important benefits, such as stabilizing shorelines, filtering water, and providing habitat for estuarine fish. However, quantifying fish use of restored oyster reefs can be difficult. Traditional sampling methods do not record all fish species and are often conducted only intermittently. As a result, fish diversity and resulting conservation and restoration decisions often rely on incomplete “snapshots” in time.
Luckily, many fish and invertebrates make sounds to communicate, navigate, and feed, providing the opportunity to “listen in” to learn about what species are present, when they are present, and what behaviors they exhibit on restored reefs.
Passive acoustic recording offers a non-destructive method to gather data on species of ecological and economic importance that traditional sampling misses. This information is vital for understanding fish behavior, including when and where certain species are spawning—a key to conservation and for establishing targets for habitat restoration.
Researchers at NC State University monitored oyster cultch reefs for two years following restoration, using a combination of traditional net and trap fish sampling and underwater acoustic surveys. In North Carolina, oyster cultch reefs are constructed primarily to provide oysters for harvest, and the NC State team wanted to determine their value as fish habitat, which is currently unknown.