MMS ENVIRONMENTAL STUDIES PROGRAM: ONGOING STUDIES
MMS OCS Region: Pacific
Title: Ecological Performance of OCS Platforms as Fish Habitat off California
Total Cost: $175,000.00 Period of Performance: FY2003-2005
Conducting Organization: University of California-Santa Barbara, CA
MMS Contact: Dr. Ann.S.Bull
Description:
Background
At this time there are several key issues in the Pacific OCS platform reefing debate. None more important than defining the ecological performance and role that platforms off California have to play in the recovery of rockfish populations in southern California. Populations of rockfish at platforms and the platforms as habitat themselves may prove to be vital for local rockfish recovery. The Department of Commerce in January 2000 declared the West Coast rockfish fishery a disaster with extremely small populations remaining. The Pacific Fishery Management Council and the State of California began to severely restrict fishing for these species in 2002 and 2003. Also in 2002, bocaccio, a rockfish species know to inhabit POCSR platforms in large numbers was a candidate for listing as threatened under the Endangered Species Act. MMS funded studies have shown that some of the platforms hold reproductively mature bocaccio and cowcod in numbers far greater than any natural reefs that have been surveyed. In addition, several species, such as bocaccio, widow and blue rockfishes have recruited as juveniles in far greater numbers to platforms than to most of the local reefs. Evaluation of the ecological performance of natural reefs and platforms can be attempted by assessing reproduction, growth rates, survivability, and mortality of the different local rockfish populations.
Objectives
The primary goal of this study is to determine the ecological performance of offshore platforms as habitat for rockfish and as producers of rockfish when compared to natural reefs. Emphasis will be placed on two severely depleted rockfish species, bocaccio and cowcod. Ecological performance may be defined as the suite of vital rates (reproduction, growth, and mortality) of a population which develop under local habitat conditions. It can be expanded to address 1) how well platforms, as habitat, sustain newly settled larvae, juveniles as they mature; and fully adult rockfish, and 2) what is the relative importance to local stocks of the reproductively mature rockfish, newly settled larvae, and juveniles at platforms when compared to those at natural reefs. The study will be accomplished in part using archived samples, videotapes, and past survey data.

Specific objectives of this study are:
 
  1. To estimate the potential annual production of larvae from reproductively mature cowcod and bocaccio at an offshore platform versus natural reefs.
  2. To determine and compare the growth rate and physiological condition of YOY rockfish and other juvenile fishes that settle at platforms versus nearby natural reefs.
  3. To estimate the mortality rates of juvenile rockfishes and other juvenile fishes at platforms versus natural reefs.
  4. To synthesize the data into a report describing the ecological performance of platforms as rockfish habitat and as rockfish producers off California.
Methods
Using archived videotapes and fish survey data from OCS Study MMS 99-0015, 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, the Contractor will estimate fish biomass and potential annual larval production and daily growth rate of bocaccio and cowcod at an offshore platform and natural reefs using density, size structure, and fecundity-length data collected in the visual surveys.The Contractor will perform statistical analyses to determine if there is a difference in fish density, biomass, or fecundity between reproductively mature bocaccio and cowcod at Platform Gail and natural reefs. The Contractor will also determine the percentage of the total surveyed population of reproductively mature cowcod and bocaccio that is located at Platform Gail and the importance of their potential annual larval production to local rockfish populations. The Contractor will also perform additional analyses to help clarify the role that rockfish populations at platforms play in local rockfish production. The Contractor will conduct weekly counts and tagging studies of juvenile rockfish during the juvenile recruitment and growth seasons to determine their species composition, density, mean size, and rate of decline over time.
Importance to MMS
The 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 assessing of habitat quality greatly bears upon platform decommissioning issues, as questions about the ecological role of Pacific OCS platforms are still unresolved.
We received information that showed that the fish populations at Pacific platforms are important to regional production, not just on the local scale. This was a crucial point for many people considering the habitat value of the platforms off California. The MMS contracted the study for decision-making and NEPA analysis purposes when the time comes for decommissioning. The deliverable will make those decisions much more efficient, understandable, and defendable.
Current Status:
The study is complete MMS OCS Study No 2004-005.
Hardcopies and CD digital version are available from the MMS Pacific Region
for a copy contact Janice Hall (janice.hall@mms.gov) or 805-389-7621
Final Report Due: 4/21/2006
Publications: 2005 Love, M. S. D. M. Schroeder, and W. H. Lenarz. Distribution of bocaccio (Sebastes paucispinis) and cowcod (Sebastes levis) around oil platforms and natural outcrops off California with Implications for larval production. Bull. Mar. Sci. 77:397-408.
2006 Love, M. S., E. Brothers, D. M. Schroeder, and W. H. Lenarz. (In Press) Ecological performance of young-of-the year blue rockfish (Sebastes mystinus) associated with oil platforms and natural reefs in California as measured by daily growth rates. Bull. Mar. Sci. Submitted for Publication.

Emery, B. M., L. Washburn, M. S. Love, M. N. Nishimoto, and J. C. Ohlmann. Do oil and gas platforms off California reduce recruitment of bocaccio (Sebastes paucispinis) to natural habitats? Analysis on trajectories derived from high frequency radar. Fish. Bull.

Gharrett, A. J., A. K. Gray, and M. S. Love. Phylogeographic divergence between the gopher (Sebastes carnatus) and black-and-yellow (S. chrysomelas) rockfishes based on mtDNA restriction site analysis. Mol. Ecol.

Li, Z., M. M. Nishimoto, A. K. Gray, M. S. Love, and A. J. Gharrett. Identification of southern California juvenile rockfish (genus Sebastes spp.) by restriction site analyses of the mitochondrial ND3/ND4 region. Fish. Bull.

Love, M. S., D. M. Schroeder, and D. Witting. A characterization of the fish assemblage of deep photic zone rock outcrops in the Anacapa Passage, Southern California, 1995 to 2002. Fish. Bull.

Love, M. S. and A. York. The role of bottom crossbeam complexity in influencing the fish assemblages at California oil and gas platforms. Fish. Bull.

Love, M. S., D. M. Schroeder, W. Lenarz, A. MacCall, A. Scarborough-Bull, and L.
Thorsteinson. The unexpected utility of offshore marine structures in rebuilding an
overfished species. Can. J. Fish. Aquat. Sci.

Love, M. S. D. M. Schroeder, and W. H. Lenarz. Distribution of Bocaccio (Sebastes paucispinis) and Cowcod (Sebastes levis) around Oil Platforms and Natural Outcrops off California with Implications for Larval Production. Bull. Mar. Sci.
Affiliated WWW Sites: The Love Lab UCSB Recent Research
Revised date: April 21, 2006
ESPIS

ESPIS - All completed ESP Studies:
Full Text, Online, Right Now!
 Environmental Studies Program Information System