Sanddab Feeding Guild 199 1 City of San Diego, Metropolitan Wastewater Department, 4918 N. Harbor Dr. Rm. 201, San Diego, CA 92106 Comparability of Bioaccumulation Within the Sanddab Feeding Guild in Coastal Southern California M. James Allen, Shelly L. Moore, Stephen B. Weisberg, Ami K. Groce 1 , and Molly Leecaster ABSTRACT M ost assessments of fish tissue contami nation in southern California are site specific, resulting in the assessment of ecologi- cally or bathymetrically different species of unknown comparability. Previous studies have not addressed whether contaminant concentrations are comparable among ecologically similar species (i.e., a guild), even though individual species might occur at different depths. To assess whether a guild approach might be useful for comparing relative fish contamination among sites with different species, we collected samples of 4 species of the sanddab guild at 22 sites where species pairs co- occurred. Sampling was conducted using 7.6-m (headrope) otter trawls in July and August of 1997. Total DDT concentrations were determined from homogenized whole fish composites. Analysis focused upon three questions: (1) are tissue contaminant levels in co-occur- ring sanddab guild species pairs correlated? (2) if so, are the relationships linear and uniform, or are corrections needed to relate responses in one species to another? and (3) how does the variability in bioaccumulation among species, sites, and ages compare to that within same-aged individuals of a species at a site? Log-transformed DDT concentrations were highly correlated among all species pairs within the sanddab guild. All of the relationships were linear over the range observed, with slopes not statistically distinguished from unity. The variability in response among species was about 4 times the variability encountered among replicates within species, but was 15 times smaller than the variability among the sites sampled. Together, these results suggest that the sanddab guild, which is represented on soft bottoms throughout the southern California coastal shelf, can be used as a “superspecies” in regional assessments of fish tissue contamination that require assessment of relative condition among sites inhabited by different species. INTRODUCTION Concentrations of dichloro-diphenyl-trichloroethane (DDT) in fish tissues on the Palos Verdes Shelf have historically been among the highest in the nation (Mearns et al. 1988). Most of this contamination can be traced to manufacturing-related discharges that ceased in the early 1970s. Although tissue contaminant levels have de- creased substantially since that time (Mearns et al. 1988, SCCWRP et al. 1992, SCCWRP 1994, Schiff and Allen 1997), commercial fishing of white croaker (Genyonemus lineatus) on the Palos Verdes Shelf is still banned because of high DDT concentrations in edible muscle tissue and DDT-contaminated fish are still present in local markets (Gold et al. 1998). While extensive data have been collected to docu- ment fish contamination, these data are not easy to integrate for a regional assessment of the extent of tissue contamination in the Southern California Bight (SCB) and the relative degree of contamination among different