CONTENTS Executive Summary v Chapter 1 1-1 Introduction Chapter 2 2-1 The Ecological Role of Oil and Gas Production Platforms and Natural Outcrops on Fishes in A Brief History of Oil Development in Southern California Southern and Central California: A Synthesis of Information Chapter 3 3-1 A Review of Biological and Oceanographic Surveys: Results and Analyses OCS Study MMS 2003-032 Disclaimer Chapter 4 4-1 This research was conducted under a cooperative agree- A Guide to Ecological and Political Issues Surrounding Oil Platform Decommissioning in California Milton S. Love ment (Agreement 1445-CA09-95-0836) between the U. S. Chapter 5 5-1 Donna M. Schroeder Geological Survey (Biological Resources Division) and the Research and Monitoring Recommendations Mary M. Nishimoto University of California, Santa Barbara. This report was re- viewed and approved for publication by the BRD. Approval Acknowledgements and Personal Communications 5-3 Marine Science Institute does not signify that the contents necessarily reflect the views References R-1 University of California and policies of the BRD or MMS, nor does mention of trade Tables T-1 Santa Barbara, CA, 93106 names or commercial products constitute endorsement or Appendices email address (for M. Love): [email protected] recommendation for use. www.id.ucsb.edu/lovelab Appendix 1 A-1 Report Availability Appendix 2 A-11 June 2003 Available for viewing and in PDF at: www.id.ucsb.edu/lovelab Appendix 3 A-13 Prepared under Cooperative Agreement #1445-CA09- Appendix 4 A-29 95-0836 between the Biological Resources Division, U. S. Reprints available at: Geological Survey, and the Marine Science Institute, Uni- Milton Love versity of California, Santa Barbara, in cooperation with Marine Science Institute the Minerals Management Service, Pacific OCS Region. University of California, Santa Barbara Santa Barbara, CA 93106 Front Cover: Background, young-of-the-year rockfishes, (805) 893-2935 Platform Grace (Mary Nishimoto). From upper left: Seastars and mussels, midwater, Platform Holly (Dan Lyman Thorsteinson Dugan); Platform Irene (Linda Snook); juvenile bocaccio, Western Fisheries Research Center midwater, Platform Gilda (Donna Schroeder); young-of- U. S. Geological Survey the-year yellowtail rockfish, Platform Irene (Rick Starr); 6505 NE 65th St. flag rockfish, Platform Grace (Donna Schroeder); young- Seattle, Washington 98115 of-the-year cowcod, shell mound, Platform Gail (Milton (206) 526-6569 Love); juvenile vermilion rockfish, bottom, Platform Grace (Donna Schroeder). Minerals Management Service Pacific OCS Region Back Cover: Kelp rockfish and club anemones, midwater, 770 Paseo Camarillo Platform Holly (Dan Dugan). Camarillo, CA 99010 (805) 389-7800 Project Cooperation This research addressed an information need identi- Suggested Citation fied by the U. S. Department of the Interior’s Minerals Love, M. S., D. M. Schroeder, and M. M. Nishimoto. 2003. Management Service, Pacific OCS Region, Camarillo, The ecological role of oil and gas production platforms California. and natural outcrops on fishes in southern and central California: a synthesis of information. U. S. Department of the Interior, U. S. Geological Survey, Biological Re- sources Division, Seattle, Washington, 98104, OCS Study LINDA SNOOK MMS 2003-032. Mexican rockfish at bottom of Platform Gail. ii iii EXECUTIVE SUMMARY Information Needed munity structure of reef fishes, and 3) describing the Production of oil and gas from offshore platforms spatial and temporal patterns of fish diversity, abundance has been a continual activity along the California coast and size distribution among habitat types (e. g., platforms since 1958. There are 26 oil and gas platforms off Califor- and natural outcrops). nia, 23 in federal waters (greater than 3 miles from shore) and 3 in state waters. The platforms are located between Research Summary 1.2 to 10.5 miles from shore and at depths ranging from Between 1995 and 2001, we studied oil and gas plat- 11 to 363 m (35–1,198 ft.). Crossbeams and diagonal forms sited over a wide range of bottom depths, ranging beams occur about every 30 m (100 ft.), from near the between 29 and 224 m (95 and 739 ft.) and sited from surface to the seafloor. The beams extend both around north of Point Arguello, central California to off Long the perimeter of the jacket and reach inside and across Beach, southern California. However, most of the plat- the platform. The beams and vertical pilings (forming the form research occurred in the Santa Barbara Channel and jacket) and the conductors on all platforms are very heav- Santa Maria Basin. The Santa Barbara Channel and Santa ily encrusted with invertebrates and provide important Maria Basin are situated in a dynamic marine transition habitat for fishes. The seafloor surrounding a platform zone between the regional flow patterns of central and is littered with mussel shells. This “shell mound” (also southern California. The Santa Barbara Channel is about called “mussel mound” or “shell hash”) is created when 100 km long by about 50 km wide (60 x 20 miles) and is living mussels, and other invertebrates, are dislodged and bordered on the south by the Northern Channel Islands fall to the seafloor during platform cleaning or storms. (San Miguel, Santa Rosa, Santa Cruz, and Anacapa). This Once an industrial decision is made to cease oil and area is bathed in a complex hydrographic system of cur- gas production, managers must decide what to do with rents and water masses. Generally, cool coastal waters the structure, a process known as decommissioning. Plat- from the California Current enter the Santa Barbara form decommissioning can take a number of forms, from Channel through its west entrance at Point Conception. leaving much, or all, of the structure in place to complete Warm waters from the Southern California Bight flow removal. Along with the platform operator, many federal in the opposite direction into the channel through its and state agencies are involved in the decommissioning eastern entrance. Surface waters are substantially warmer process. All oil and gas platforms have finite economic in the Bight than north of Point Conception due to less lives and by the beginning of the twenty-first century, wind-induced vertical mixing, the solar heating of surface seven platforms in southern California had been decom- waters, and currents of subtropical waters entering from missioned and a number of others appeared to be nearing the south. The convergence of different water masses in the end of their economic lives. the Santa Barbara Channel results in relatively large scale Management decisions regarding the decommis- differences in physical parameters (e.g., temperature, sa- sioning of an oil and gas platform are based on both linity, oxygen, and nutrient concentrations) and biotic biological and socioeconomic information. This study assemblages (e. g., flora and fauna). addressed the need for resource information and better Scuba surveys were conducted at shallow depths understanding of how offshore oil/gas platforms con- and submersible surveys, using the research submarine tributed to the fish populations and fishery productivity Delta, at greater depths. We also surveyed shallow-water in the Santa Maria Basin and Santa Barbara Channel. and deeper-water rock outcrops, many in the vicinity of Prior to our studies, there was almost no biological in- platforms. Nine nearshore, shallow-water rock outcrops, formation on Pacific Coast platform fish assemblages. seven on the mainland and two at Anacapa Island, were This necessary research involved broad scale sampling at monitored annually from 1995 to 2000. These natural numerous oil/gas platforms and natural reefs. Research outcrops are geographically distributed across the Santa objectives included 1) characterizing the fish assemblages Barbara Channel providing opportunities for spatial around platforms and natural reefs, 2) examining how comparisons. In addition, we surveyed over 80 deeper- oceanography affects patterns of recruitment and com- water outcrops, in waters between 30 and 360 m (100 v Opposite: Juvenile widow rockfish in platform midwater. (Photograph by Lovelab, UC Santa Barbara) EXECUTIVE SUMMARY EXECUTIVE SUMMARY and 1,180 ft.) deep, located throughout the Southern Characterization of the Deepwater young-of-the-year and older juveniles of such species as uges. High fishing pressure on most rocky outcrops in California Bight and off Points Conception and Arguello. Platform Fish Assemblages lingcod and copper, flag, greenblotched, and pinkrose central and southern California has led to many habitats These sites included a wide range of such habitats as With the exception of the shallow-water Platform rockfishes and cowcod. The adults of these species also almost devoid of large fishes. Fishing pressure around banks, ridges, and carbonate reefs, ranging in size from Gina, all of the platforms we surveyed were characterized inhabited the platform bottom. most platforms has been minimal. In some locations, a few kilometers in length to less than a hectare in area. by three distinct fish assemblages: midwater, bottom, and platforms may provide much or all of the adult fishes of On these features, we focussed on hard bottom macro- shell mound. Rockfishes, totaling 42 species, dominated Platform versus Reef Fish Assemblages some heavily fished species and thus contribute dispro- habitats, including kelp beds, boulder and cobble fields, these habitats. Fish densities at most platforms were high- We compared the species composition of the fish portionately to those species’ larval production. and bedrock outcrops. Most of these deeper-water sites est in the midwater habitat reflecting the depth prefer- assemblages at Platform Hidalgo and at North Reef, Platforms usually harbored higher densities of young- were visited once, a few were surveyed during as many ences of young-of-the-year rockfishes. Young-of-the-year an outcrop located about 1,000 m (3,300 ft.) from the of-the-year rockfishes than natural outcrops and thus may as four years and one outcrop, North Reef, near Platform rockfishes represented the most abundant size classes in platform.