Studies on diet and feeding ecology are necessary to determine trophic links between organisms and to estimate energy transfer within ecosystems. In addition, changes in both community structure and physical conditions may be monitored through an evaluation of dietary changes. Elasmobranchs have played important roles in marine ecosystems throughout their history, often occupying the highest trophic levels as apex predators. Despite the central importance of feeding relationships in understanding trophodynamics and community structure, little is known about the feeding ecology of elasmobranchs. To address this general lack of information, research projects involving commercially landed species have been developed by the PSRC. Diet and feeding ecology are currently being investigated from shark and skate specimens collected from surveys conducted by the NMFS Southwest Fisheries Science Center Santa Cruz Lab. Species currently being examined are the sandpaper skate (Bathyraja kincaidii), California skate (R. inornata), longnose skate (R. rhina), brown catshark (Apristurus brunneus), and filetail catshark (Parmaturus xaniurus).