29 



depth of horizon at which they exist, from shallow 

 (a few feet), to slope and deep (2940 feet) areas (see 

 Zones I to VI for the major areas in Santa Monica Bay), 

 They can also be classified according to biological 

 requirements, such as varying amounts of dissolved 

 oxygen, or lack of it (the near absence of life in sub- 

 sill parts of Santa Monica Basin may be the result of 

 such a lack)o These animals can be classified according 

 to their feeding habits as predators or scavengers 

 (living on dead animal food), carnivores (f lesh=eaters) , 

 herbivores (plant feeders), detritus feeders (such as 

 most animals near Hyperion), limnivores (ingesting mud 

 with contained microorganisms), filter feeders (straining 

 water containing nutrients), or as commensals or parasites 

 (depending on other animals for their food)o All of these 

 are represented in Santa Monica Bayo In normal habitats, 

 all feeding groups can be expected to be represented in 

 an associationo In the environs of the outfall, however, 

 most species are detritus feeders(polychaetes and Astro - 

 pecten )o Predators are occasional, entering the area as 

 foragers (such as larger Cancer crabs, frog snail, and 

 flounder fishes)o 



Species vary according to tolerances to salinity 

 so that near the outfall where large volumes of nonmarine 

 water are introduced, most echinoderms, mollusks, many 

 entoraostracans and polychaetes are unable to exist » As 

 the effects of these dilutions decrease, the number of 



