Dead rockfish were observed throughout the Sound immediately following the spill, but an absolute count was never documented. Necropsies of five fish indicated that oil ingestion was the cause of death. Additionally, hydrocarbon concentrations in dead fish from oiled areas were higher than those from unoiled areas. Closures to salmon fisheries apparently caused increasing fishing pressure on rockfish, which may have adversely affected local populations.
Due to the continuing lack of data on rockfish, no recovery objective can be identified.
From 1989–1991, higher petroleum hydrocarbon concentrations were measured in rockfish from oiled areas when compared to unoiled areas. Interpretation of these data is limited, however, because oil accumulation differs by species and by age of the fish, and these variables were not fixed across sites. Other Council-funded studies have been conducted on rockfish since the spill, including 1) an examination of larval growth of fish, (including rockfish) in 1989; 2) a genetics investigation designed to identify species of rockfish larvae and young in the Gulf of Alaska and 3) a microscopic examination of fish tissues to identify lesions associated with oil exposure. These studies were inconclusive as none of them directly linked exposure of Exxon Valdez oil to any of the endpoints that were measured.
It is unlikely that rockfish are currently being exposed to lingering oil because known pockets of lingering oil rarely occur in their preferred habitat. Documented lingering bioavailable oil is in the subsurface sediments of the intertidal zone, and rockfish mostly occur in differing habitats of subtidal areas and in pelagic environments. From 1999–2000, no differences were measured in physiological responses to oil in rockfish from oiled and unoiled areas.
Since the spill, few studies have provided information about rockfish abundance, species composition and the impacts of commercial fisheries. Although it is unlikely that most species and life-stages of rockfish are currently being exposed to lingering oil, the original extent of injury was not documented. Rockfish do utilize the nearshore environment as young-of-the-year and juvenile rockfish. Since lingering oil is present in the intertidal zone, the risk of exposure may be present during early life history stages.
Therefore, the current understanding of the long-term effects of the original spill cannot be determined and rockfish are VERY LIKELY RECOVERED. In addition, based on the available data, understanding of ecological interactions and the expected small size of lingering impacts, it is unlikely that an effect, if any, will impair function of the ecological system and, thus, there are likely more effective uses of research funds than on further study of this species.
Click HERE for more information on Trustee Council funded studies of rockfish.