The biology of two offshore oil platforms

Abstract

Surveys were conducted in 1975 on platforms Hazel and Hilda in the Santa Barbara Channel. “A total of 290 species of mammals, birds, fish and invertebrates were seen on or under the platforms or found in samples of the fouling community and nearby sediments. Every support member and oil conductor pipe underwater was coated with a fouling community 1 to 4 feet thick. The colonial anemone Corynactis californica was present at all depths on both platforms and appeared to be the most abundant macroinvertebrate. However, mussels, in particular, Mytilus californianus, dominated the invertebrate communities…   

Forty-five species of fish were seen in direct association with the platform…The number of species seen during a single visit to a platform ranged from 8 to 31. Although about 50 percent of the fish present were rockfishes, no one species seemed to make up more than 30 percent of the total fish population. The community of organisms in a soft-bottom area where there were no platforms was different from the community associated with the platforms, both in kinds and numbers of animals. Divers estimated that a portion of the soft bottom the same size as the platforms supported less than 500 fish (the estimates of the number of fish present at the oil platforms on different dsays ranged fro 8,000 to 30,000).”