oriented north, south, east, and west of the station marker. Estimates of 

 species abundance and community structure were made by habitat type. We also 

 collected surficial sediment samples, and animal samples (tilefish, scallops, 

 lobsters, and Jonah crabs) for tissue analysis. 



We have classified the habitats of the canyon region as follows: 



■ Type 1: Flat, featureless, with less than 5 percent overlay of rock 

 and gravel; accounts for approximately 60 percent of canyon heads. 



■ Type 2: Similar to Type 1, but with more than 5 percent overlay of 

 gravel and rock; about 10 percent of canyon head area. 



■ Type 3: Boulder field, highly productive of fishery resources; 

 occupies about 5 percent of canyon head area. 



■ Type 4: "Pueblo Village" environment; very important in fisheries; 

 accounts for some 20 percent of canyon head area. 



■ Type 5: Sand dune and sand wave environment of the canyon axis; 

 occupies less than 5 percent of the canyon head area. 



Canyons function as important nursery grounds for a wide variety of 

 megabenthic fauna such as shrimps, cancer crabs, lobsters, white hake, cusk, 

 ocean pout, conger eel, tilefish, black-bellied rosefish, etc. They provide 

 shelter that rarely occurs in noncanyon areas of the outer shelf and upper 

 slope for the adults of some 20 species. Our combined canyon studies show 

 that the surficial geologic features of the canyon heads support unique 

 ecosystems, largely because of their highly varied character. 



We conclude that submarine canyons are complex three-dimensional 

 environments where there is little, if any, impact from active fishing gear; 

 they serve as refugia for many bottom-oriented species. Species diversity and 

 abundance are greater in canyons than in noncanyon areas at comparable depths. 



- 6 



