Right Column
Mineral Resources Management Division - Rigs to Reefs Workshop
Dr. Milton Love |
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Dr. Love is an Associate Research Biologist at the Marine Science Institute, For the past 30 years, he has been involved in research on the biology and ecology of the recreational and commercial fish species of California. With funding from the Biological Resources Division of the U.S. Geological Survey, Dr. Love and his associates are conducting research on the ecological role of natural reefs and oil and gas production platforms on rocky reef fishes in Southern California. |
| ~Submitted by Dr. Love ~ |
The Fish Communities of Seven Oil/Gas Production Platforms in the Santa Barbara Channel and Santa Maria Basin
Beginning in 1996, we have surveyed the fishes living on and around seven offshore oil platforms in the Santa Barbara Channel region. We conducted belt transects at various depths in the midwater and around the bottoms of each platform using the research submersible Delta. The bottom depths of these platforms ranged from 49 to 224 m and the midwater beams ranged from 21 to 196 m. We surveyed two bottom habitats, 1) that formed by the platform structure and 2) that composed of shells and other organisms that had fallen from the platform (the "shell mounds"). We found that there were several distinct differences in the fish assemblages living in the midwater and bottom habitats around all of the platforms, all assemblages were dominated by rockfish. Platform midwaters were dominated by young-of-the-year (YOY) or juveniles up to two years old. Rockfishes larger than about 18 cm total length were rarely seen in the midwater. The fish communities around the bottoms of the platforms were dominated by larger individuals, primarily subadults or adults. There was a consistently greater number of species on the bottom compared to the midwater of each platform, likely due to a larger variety of habitat types on the bottom. The fish communities also differed among platforms. We observed at least 35 species of fishes on the shell mounds, 18 of which were rockfishes. Most of thc species that were found both in large numbers and were encountered at a number of shell mounds were solitary, benthic forms. Species richness, density (fish/100 ma) and mean lengths of fishes were all less on the shell mounds than on the platform bottoms. However, cluster analysis revealed that the species composition on each shell mound is more similar to its adjacent platform bottom than to other mounds. There did not appear to be a distinct "shell mound community", instead the shell mounds should be considered an integral part of the oil platform system.