Pelagic Environment 



157 



Figure 1 36. Pacific pilot whale, 

 Globicephala scammoni Cope, 

 about 4 meters long. This one 

 was captured and placed on 

 exhibit in a large tank (Norris, 

 1958). Courtesy Marineland 

 of the Pacific. 



shearwaters than of the shore-based cormo- 

 rants, peHcans, and gulls. The albatrosses, 

 mostly Diomedea nigripes, live far from 

 shore, spending nearly all their lives on the 

 water or wheeling gracefully just above it. 

 Since they feed on zooplankton and what- 

 ever nekton comes their way, they are far 

 more abundant in the belt of cold water near 

 the Santa Rosa-Cortes Ridge than farther 

 seaward or landward where plankton is less 

 abundant (Miller, 1940). 



Mesopelagic Zone 



Much less is known about the organisms 

 that live deeper than a few hundred feet, 

 owing to the difficulty of observing and col- 

 lecting them. Observations at these depths 

 must be made by instruments or men housed 

 in pressure-tight containers (Piccard and 

 Dietz, 1957; Peres, 1958) and collections 

 made mostly by nets dragged through the 

 water. Because many of the animals that 

 can be observed are too small or too fragile 

 to be caught in nets, and because many of 

 those that can be recovered in nets are too 



mobile or too widely dispersed to be readily 

 observed, there are some discrepancies in 

 results obtained by the two methods. 



Photographs made by the benthograph 

 (Emery, 1952a) showed large numbers of 

 tiny light-scattering objects mostly between 

 depths of about 100 and 1000 feet (Fig. 

 137). Most were too small to have any 

 character. Very likely they are the same as 

 the "snow" that has repeatedly been ob- 

 served during dives of the bathyscaphes 

 F.N.R.S. III and Trieste in the Mediter- 

 ranean Sea and the nearby Atlantic Ocean. 

 Peres and Piccard (1956) reported that the 

 "snow" consists of inactive particles rang- 

 ing from the size of peas to an amorphous 

 mist, plus filamentous material as long as 

 16 inches. The depth range is the same as 

 observed by photography off southern Cali- 

 fornia. Hardy (1956, p. 240) added the in- 

 teresting suggestion that the "snow" may 

 consist largely of the cast skins of the tiny 

 crustaceans of zooplankton. Unfortunately, 

 no worthwhile observations from manned 

 devices have yet been reported from this 

 region. 



