A Histological Examination of the Ovaries of Pacific Sanddab, Citharichthys sordidus, Captured at Two Oil Platforms and Two Natural Sites in the Southern California Bight

—A number of the 26 offshore oil and gas platforms off California may be nearing the end of their economic lives. Decisions as to the disposition of these platforms will be based on a number of parameters, including the biological role of the structures. One issue that has arisen is the possible contamination of fishes living around platforms resulting from contaminants released during drilling and production. If significant contamination is occurring, it would be expected to impair the reproductive abilities of impacted fishes. One form of reproductive impairment is atresia, the abnormal reabsorption of oocytes that are destined to be spawned. Atresia has been widely used as an indicator of pollutant-related reproductive impairment in fishes. We examined the occurrence of atretic oocytes in Pacific sanddab, Citharichthys sordidus, collected near two offshore platforms in the Santa Barbara Channel (B and Gilda) and from two natural reference sites (off the east end of Santa Cruz Island and in mid-channel off Rincon). While pronounced atresia was observed in a few fish at one natural site and one platform, there was no evidence of widespread pronounced atresia at any of the four sites. There are 26 offshore oil and gas platforms in California waters, many of which may be nearing the ends of their economic life spans. Following the decision by an operator to cease production, the process by which a decision is made as to the disposition of a platform is called decommissioning. This procedure may take into consideration the biological, sociological, and economic consequences of various decommissioning options, which range from leaving the entire structure in place through partial or total removal (Schroeder and Love 2004). Among the issues that need to be addressed in this process is the possible contamination of platform-dwelling organisms. A number of activities associated with the production of oil and gas result in the creation of contaminants. Drilling muds (used to lubricate drill bits), drill cuttings (the hard material brought up by the drill bit), the water associated with the petroleum produced (‘‘produced water’’), and water used as coolant contain a variety of elements and compounds, including petroleum hydrocarbons (such as polycyclic aromatic hydrocarbons (PAHs)) and metals (Utvik 1999; Neff 2002; Steinberger et al. 2004). At least some of these elements and compounds are released into the water and may be deposited on the sea floor around these structures (Grant and Bull. Southern California Acad. Sci. 108(2), 2009, pp. 45–51 E Southern California Academy of Sciences, 2009