The Effects of Weathered Crude Oil from the M/T Alvenus Spill on Eggs and Yolk-Sac Larvae of Red Drum (Sciaenops ocellatus)

Abstract

The Biitish tanker M/T ALVENUS ran aground 16.1 km south of Cameron, Louisiana, on 30 July 1984. An estimated 10,157 MT of Venezuelan crude oil were spilled into the Gulf of Mexico. Approximately 2,700 MT of the heavy viscous oil impacted beaches and an additional 1,360 MT remained in the subtidal areas of west Galveston Island, about 160 km southwest of the accident site. Red drum, which spawn in the Gulf of Mexico in the fall, could have been seriously impacted by oil concentrations potentially lethal to eggs or larvae. The impact of weathered crude oil on the survival, growth, and morphological development of red drum eggs and larvae was assessed in the laboratory. Equal numbers of eggs were randomly assigned to one of six treatments of weathered crude oil (control, 50, 100, 500, 1,000 and 2,000 mg/l) and observed through the yolk-sac stage. There were no differences in mean survival, length of surviving larvae, and frequency of morphological abnormalities among treatments (01 4 0.05). In addition, the frequency of spinal deformity and abnormal mouth development was low in all treatments. The initial chemical composition of the fresh crude oil and the seasonally warm weather contributed to the natural degradation of the soluble toxic components.