EFFECTS OF CONTAMINATED SEDIMENTS ON VIABILITY, LENGTH, DNA AND PROTEIN-CONTENT OF LARVAL SURF SMELT, HYPOMESUS-PRETIOSUS

Mortality, abnormal morphology, growth, DNA and protein content of lar val surf smelt (Hypomesus pretiosus) were evaluated after 96-h exposur es to contaminated sediments from Puget Sound, Washington. Radiolabele d polynuclear aromatic hydrocarbons (PAHs) and polychlorinated bipheny ls (PCBs) added to sediment were accumulated by exposed larvae, provid ing evidence of an exposure route for hydrophobic compounds from the s ediment to the larvae. Sediment mixtures with high concentrations of c ontaminants were often acutely toxic, while exposure to diluted sedime nts resulted in sublethal changes-decreases in growth and DNA content. The DNA content of larvae was found to be the most sensitive of the s ublethal measures. Both DNA content and the proportion of normal larva e were inversely related to PAH and PCB concentrations of test sedimen ts. The results suggest that measurement of DNA content in conjunction with determination of the proportion of normal larval surf smelt can provide better discrimination for assessing toxicity due to contaminan ts in this sediment bioassay system than measurement of mortality alon e. Because some larval fish may be at risk to sediment-associated cont aminants, this bioassay may be useful for assessing the effects on lar val marine fishes exposed to contaminants.