I. OBJECTIVES1) Use large chevron traps and demersal longlines to describe and examine differences in the species assemblages and relative abundances of demersal fishes associated with the eastern and western walls of DeSoto Canyon and the adjacent continental slope (75-2000 m deep).2) Collect liver and bile samples from dominant species to examine spatial and depth-mediated differences in exposure to polycyclic aromatic hydrocarbons (PAHs).3) Collect muscle tissue from all species for stable isotope analyses including using radiocarbon ratios to examine attenuation of long-term exposure to hydrocarbons.4) Collect specimens and samples (including curation of new species) to aid in resolving phylogenetic uncertainties and understanding life history traits in collected taxa.