MMS ENVIRONMENTAL STUDIES PROGRAM: ONGOING STUDIES
MMS OCS Region: Pacific
Title: Benthic Invertebrate Communities On Shell Mounds Surrounding Oil And Gas Platforms In The Santa Barbara Channel And Santa Maria Basin
Actual Costs: $50,000.00
 		 Period of Performance: FY2004-2006
Conducting Organization: Unversity of California-Santa Barbara (Contact: Jeff Goddard)
MMS Contact: Dr. Ann.S.Bull
Description:
Background
The Minerals Management Service (MMS) defines decommissioning as the process of ending oil, gas, or sulfur operations and returning the lease or pipeline right-of-way to a condition that meets the requirements of the regulations. The MMS works to ensure that wells are plugged to prevent pollution; that pipelines are decommissioned to prevent seepage of hydrocarbons and removed to minimize conflicts with other uses of the OCS; and that all sites are cleared of obstructions to minimize use conflicts. The MMS will conduct detailed environmental reviews of any proposed decommissioning projects to evaluate the impacts from platform removal on regional invertebrate populations. The assessing of habitat quality greatly bears upon platform decommissioning issues, as questions about habitat and the ecological role of Pacific OCS platforms are still unresolved. Unfortunately, removing platforms also removes useful habitat, kills numerous shellfish, and may have adverse impacts on regional populations of some species on the Pacific OCS.
Objectives
Specific objectives of this study are:

1. To quantitatively document the assemblages of large invertebrates on shell mounds associated with platforms off California.
2. To investigate bathymetric and spatial patterns of abundance in the most common species and taxa.
3. To compare species assemblages among platforms.
4. Investigate the relationship between the abundance of various invertebrates and those of the more common fishes to determine if significant and previously undetected
5. Compare the density and adult size of seastar populations on the shell mounds with information on populations from natural reefs and soft bottom habitats in the southern California bight
Methods
1. Using archived videotapes and survey data from OCS Study MMS 2003-032, The Ecological Role of Natural Reefs and Oil and Gas Production Platforms on Rocky Reef Fishes in Southern California and from any other readily available source, quantitatively determine the assemblages of macro-invertebrates on shell mounds associated with platforms off California.
2. To investigate bathymetric and spatial changes in the more common invertebrates, employ a general linear model to examine the effects of depth (in three categories, <100 m, 100 – 200 m and >200 m) and position (in two categories, Santa Maria Basin or Santa Barbara Channel) with percent cover of mussels as a covariate.
3. To compare the mussel mound invertebrate assemblages among platforms, follow the methodology used by Love et al. (1999; see below) for mussel mound fish assemblages.
Importance to MMS
Knowledge of the epibenthic invertebrate communities on shell mounds, their relation to associated fishes, and their conservation potential for shallow-water populations of important shellfish and seastars, will improve our understanding of offshore oil platforms as artificial reefs, and better inform our evaluation of the ecological consequences of the various options proposed for decommissioning the platforms.
Current Status:
This study is in its final phase. Statistical analyses are completed and the draft Technical Summary and Final Reports will be received by MMS for review in December 2006.
Final Report Due: 12/22/2006
Publications: Love, M. S., J. Caselle & L. Snook. 1999. Fish assemblages on mussel mounds surrounding seven oil platforms in the Santa Barbara Channel and Santa Maria Basin. Bulletin of Marine Science 65: 497-513.
Affiliated WWW Sites:
Revised date: November 30, 2006
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