shelter, rarely occurring in noncanyon areas of the outer 

 shelf and upper slope, for the adults of some 20 species. 

 Our combined canyon studies show that these large geologic 

 features represent unique ecosytems, largely because of 

 their highly varied, three dimensional habitats. 



Examination of the benchmark data on annual variations 

 in species abundance, specifically for the fourteen 

 designated key "indicator species," suggests that no one 

 species is likely to clearly reflect anything other than a 

 major impact from production drilling. We suggest that 

 community composition be examined by habitat type and 

 specific location for defining faunal benchmarks in terms of 

 future oil and gas explorations. 



Surficial sediments at each benchmark station were 

 analyzed for trace metals (Ba, Cd, Cu, Cr, Hg, Pb, and Zn) , 

 hydrocarbons (aromatic and aliphatic), and PCB's. Scallops 

 (muscle and viscera) , cancer crabs (hepatopancreas and claw 

 tissue) , lobsters (hepatopancreas, claw/tail tissue, and 

 eggs) , and tilefish (dorsal musculature) were subjected to 

 the same analyses. Sediment and animal bound PCBs were 

 below the levels of detection (0.005 ppm) prior to 

 drilling; subsequent analyses were not made. Concentrations 

 of petrogenic hydrocarbons (FI, FIX) were all non detectable 

 prior to and after drilling. Trace metal concentrations in 

 the surficial sediments and in crabs and lobsters remained 

 relatively constant over time. 



Since no impacts were identified with regard to 

 exploratory drilling, this 5-year data base is considered an 

 appropriate "benchmark" for future drilling operations. 



B-3 



