Enhancing artificial reef fish populations by providing invertebrate prey refugia

Government and private organizations in many regions invest heavily in artificial reefs as a method of enhancing fish populations for recreational fishermen. Though these reefs are known to aggregate fish in the short-term, the long-term maintenance of elevated fish abundance may be impaired as a result of succession to an unpalatable benthic community. We tested the hypothesis that providing a spatial refuge for benthic fauna would result in elevated fish abundances on artificial reefs. Sturdy mesh bags that excluded fish predators and created a growth and reproductive refuge for fouling organisms were placed into artificial reef materials at four replicate sites off the North Carolina coast. Reef sites were subsequently surveyed using two methods: diver fish counts and professional angler success. Anglers consistently demonstrated greater catch rates on reefs with refuge bags. Diver surveys after one year also showed that total abundance of fish as well as abundance of several species was greater on experimental sites. These results indicate that including prey refuges in artificial reefs can increase fish populations and angler success. Such experimental manipulation of epibenthic prey also supports the role of productivity in controlling artificial reef fish assemblages