An Indication of the Process: Offshore Platforms as Artificial Reefs in the Gulf of Mexico

Fish and biofouling communities at three artificial reef sites in the Gulf of Mexico were monitored from 1989 through 1991. South Timbalier Block 86 Platform A (86-A) was toppled by a hurricane in 1985; South Timbalier Block 128 Platform A (128-A) was detonated and toppled in place in the fall of 1988; and South Timbalier Block 134 Platform D (l34-D) was detonated, towed, and deployed in 1991 about 30 m from 128-A. The results of a 1989 survey of fishes and invertebrates at 86-A and at 128-A suggested that the communities were more mature at 86-A. The predominance of immature fish and the paucity of adults of those same species on 128-A indicated that this artificial reef was acting as a recruitment site. Observations in 1990 at 86-A were essentially the same as those of 1989, while the communities at 128-A showed a greater diversity and maturity; however, both communities exhibited a decrease in octocoral biomass. Observations in 1991 at 86-A were essentially the same as those of 1989 and 1990, while the communities at 128-A continued to show further development. A large number of immature fish and a pioneering biofouling community at 134-D were comparable to the 1989 observations made at 128-A. Further, adult reef-dependent species were observed moving freely between 128-A and 134-D. Observations made in 1989 at 86-A and 128-A suggest that differences were related to the manner by which each structure was toppled and the length of time each had remained undisturbed; differences observed between 1989 and 1990 were related to time undisturbed and meteorological conditions of the winter of 1989; and differences recorded between 1990 and 1991 were related to continued diversification and maturation of the community at 128-A. Observations made in 1991 at 128-A and 134-D suggest that 134-D acted as a recruitment reef as well as part of a reef complex for adult reef-dependent species moving between the adjacent structures.