Emery et a\ : Do oil and gas platforms reduce recruitment of Sebastes paucispinis to natural fiabitat' 



399 



(Love et al., 2003). Thus, bocaccio that recruit as YOYs 

 to a platform may benefit natural reefs either through 

 emigration to these reefs or through increased larval 

 production. 



191). Deploying the radars was made possible through 

 cooperative agreements with the California State Parks 

 Channel Coast District, the U.S. Coast Guard, and the 

 U.S. Air Force. 



Conclusion 



Observations of evolving surface current patterns 

 obtained by HF radar are used to estimate dispersal 

 pathways for juvenile bocaccio in the vicinity of Platform 

 Irene, an oil production platform off the central Califor- 

 nia coast. Results indicate that most of YOY bocaccio 

 settling around Platform Irene would not survive in the 

 absence of the platform. Instead, prevailing currents 

 would likely advect them offshore where they would have 

 a very low probability of survival. Although it is possible 

 that some individuals would encounter acceptable nurs- 

 ery habitat on offshore banks or islands, it is likely that 

 most would perish. Thus, the presence of Platform Irene 

 almost certainly increases the survival of young bocaccio 

 in the Point Conception-Point Arguello region. 



These results indicate that knowledge of regional 

 ocean circulation patterns is essential for evaluating 

 the effects of oil production platforms, or other artifi- 

 cial habitats, on dispersal pathways of juvenile fishes. 

 Platform location, local current patterns, and natural 

 habitat distribution determine the balance between 

 settlement at a specific platform and settlement on 

 natural habitat. The approach used in this study, an 

 analysis of trajectories derived from HF radar current 

 measurements, can provide insights into this balance. 

 Additional research on small-scale circulations features 

 unresolved by the radars and on swimming behavior of 

 juvenile rockfishes will sharpen these insights. 



Acknowledgments 



We thank S. Ralston, NMFS, Santa Cruz, for providing 

 pelagic juvenile bocaccio mortality estimates; W. Lenarz 

 for YOY bocaccio abundance estimates at Platforms 

 Irene and Grace; and A. MacCall, NMFS, Santa Cruz, 

 for projected survival of the YOY bocaccio. We benefited 

 from helpful discussions with Edwin Beckenbach and 

 David Siegel. Drifter data were made available by the 

 Center for Coastal Studies at the Scripps Institution 

 of Oceanography. David Salazar and Chris Gotschalk 

 provided valuable support during field operations. This 

 research was supported by the Minerals Management 

 Service, U.S. Department of the Interior, MMS Agree- 

 ment 14-35-0001-30758; the California Artificial Reef 

 Enhancement Program; the W.M. Keck Foundation; 

 the Biological Resources Division of the U.S. Geological 

 Survey; the University of California Marine Council; the 

 National Oceanographic and Atmospheric Administra- 

 tion; and PISCO, the Partnership for Interdisciplinary 

 Studies of Coastal Oceans, funded primarily by the 

 Gordon and Betty Moore Foundation, and the David 

 and Lucile Packard Foundation (contribution number 



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