occupation of breeding areas in Baja 

 California, Mexico (Rice and Wolman 1971; 

 Oliver et al . 1983). However, there is 

 now evidence that gray whales, while 

 migrating, feed on dense swarms of mysid 

 shrimp within or along the outer edges of 

 kelp beds and forests (Wellington and 

 Anderson 1978, Poole in press, Murison et 

 al. in press). It may be advantageous for 

 a gray whale cow with a dependent calf to 

 supplement her stored reserves by feeding 

 upon the abundant mysid resource 

 associated with kelp (Poole in press). 



Killer whale (Orcinus orca) . The 

 status and distribution of the California 

 population of killer whales are not known 

 (Morejohn 1977). Killer whales feed in 

 small groups in nearshore regions, 

 particularly near areas of high marine 

 mammal concentrations (e.g., pinniped 

 rookeries; Rice 1968). Pods of killer 

 whales have been sighted traveling along 

 the edge of kelp forests (Daugherty and 

 Schuyler 1979). 



4.6.2.4 Pinnipeds . Harbor seal 

 (Phoca vitulus) . Harbor seals are year- 

 round residents of embayments, sloughs, 

 and rivers along the California coast, 

 with an estimated population of 20,000 

 individuals (Miller pers. comm.). Jones 

 (1981) describes the diet of harbor seals 

 as consisting of shallow-bottom fishes 

 that live near rock habitat, but they also 

 feed on pelagic fishes in many areas 

 (Estes pers. comm.). Greenlings and surf- 

 perch, two common groups of kelp forest 

 fishes (see Section 4.5), were included by 

 Jones as major prey items. Daugherty and 

 Schuyler (1979) pointed out that harbor 

 seals resting in thick beds of kelp with 

 their heads protruding above the surface 

 are often mistaken for sea otters. 

 Although we could locate no specific 

 reference to the harbor seal's association 

 with kelp beds, individuals are commonly 

 observed while diving in kelp and probably 

 forage extensively in kelp forests when 

 these habitats are close to seal haul-out 

 areas. Jameson (pers. comm.) has even 

 observed a harbor seal partially 

 hauled-out on a dense, floating canopy of 

 Ne reocystis luetkeana . 



California sea lion (Zalophus cali - 

 fornianus) . The California sea lion 

 breeds on the Channel Islands of southern 



California, along the coast of Baja 

 California, Mexico, and in the Gulf of 

 California during June and July. During 

 the remainder of the year, some 75,000 sea 

 lions (Bonnell pers. comm.) inhabit the 

 entire coastal region of California. 

 Groups of sea lions are sometimes seen 

 passing through kelp forests or foraging 

 along the kelp forest fringe. Sea lions 

 show a preference for pelagic prey items 

 (Jones 1981). It is probable that the 

 association of sea lions with kelp forests 

 is limited to transitory foraging, 

 although these animals are commonly 

 observed in kelp forests by divers. 



4.6.2.5 Steller's sea cow (Hydro - 

 damalis gigas) . Giant kelp forests were, 

 in the past, probably also inhabited by 

 the now-extinct Steller's sea cow. This 

 huge (6,000 kg, over 7 m long; Domning 

 1978) herbivorous mammal is believed to 

 have inhabited nearshore areas from Baja 

 California, Mexico, to Russia. Probably 

 as a result of hunting by aboriginal man, 

 only an estimated 2,000 animals remained 

 in the remote portions of the western 

 Aleutian Islands and eastern Russia by 

 1741, and the last animal is believed to 

 have been killed in 1768 (Domning 1978). 



Hydrodamalis gigas apparently did not 

 completely submerge, and fed on various 

 seaweeds and sea grasses in very shallow 

 (probably 1-2 m) water (Domning 1978). 

 Its shallow subtidal habitat, lack of 

 diving, and slow movements made this 

 sirenian easy prey for hunters. Dayton 

 (1975) suggested that sea cow grazing may 

 have been important in the evolution of 

 algal assemblages in kelp forests. 

 However, given what is known of the sea 

 cow's habitat and method of feeding, this 

 is arguable. Although apparently never 

 observed, sea cows could have fed on 

 surface canopies in deeper water. 



4.7 DISEASES 

 4.7.1 Introduction 



A variety of pathogens and parasites 

 infect macro-organisms in giant kelp 

 forests, but except for a limited number 

 of cases reviewed below, little is known 

 of their effects on host populations. 



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