IMPACTS ON INTERTIDAL EPIBIOTA: EXXON VALDEZ SPILL AND SUBSEQUENT CLEANUP

Abstract

ABSTRACT Following the Exxon Valdez spill, several approaches were used to remove crude oil from the beaches of Prince William Sound. Pre- and post-treatment monitoring in 1989 documented the severe short-term impacts to intertidal epibenthos of hot water wash treatments widely used to remove stranded oil. Quantitative field surveys were conducted in 1990 and 1991 to evaluate recovery of littoral habitats from the effects of oiling and hot water washing. Stratified random sampling was used to assess epibiota at sites representing several habitats and degrees of disturbance. Effects of hot water treatments applied in 1989 remained visible in intertidal assemblages through 1991. Some hot water-treated rocky beaches that had been stripped of biota at middle and upper intertidal elevations showed little colonization by 1990. In 1990, statistically significant differences were noted between variables measured on unoiled beaches and those same variables on hot water-treated beaches. On other oiled rocky beaches that received less severe or no treatment, the majority of the community dominants, including rockweed, mussels, barnacles, limpets, drills, and littorines, survived the oiling. While these populations were still depressed below abundance levels on unoiled beaches in May 1991, by July recovery of most species had raised abundances to levels seen on unoiled beaches. In the summer of 1991, few statistically significant differences remained between the biota of unoiled rocky shores and those of hot water-washed shores, but full recovery is still several years away in many areas.