between rocky reefs (Cowen pers. comm.). 

 Horn sharks are frequently found in 

 crevices or among rocks. They feed at 

 night on large crustaceans and small 

 fishes. The spiral-shaped egg cases are 

 often scattered among rocks (Feder et al . 

 1974). Leopard sharks enter kelp forests 

 for short periods, usually resting on the 

 bottom. They eat crustaceans and small 

 fishes. The angel shark buries in sand or 

 mud, where it ambushes fishes such as 

 corbina and queenfish (Feder et al . 1974). 



Other occasional visitors to kelp 

 forests include barracuda ( Sphyraena 

 argentea ) , Pacific bonito ( Sarda 

 chilensis ) , ocean sunfish or common mola 

 ( Mola mola ) , giant sea bass ( Stereolepis 

 gigas ) , the salema (Xenistius 

 cal iforniensis ) , and the jack mackerel 

 ( TrachuruT symmetricus ). Schools of 

 barracuda and Pacific bonito enter kelp 

 forests while pursuing anchovies or 

 sardines (Feder et al . 1974). Ocean 

 sunfish are weak-swimming pelagic fish 

 that are swept into kelp forests via 

 currents. Senoritas and kelp surfperch 

 remove ecotoparasites from ocean sunfish. 

 Common molas lack teeth, and consume 

 soft-bodied prey such as jellyfish and 

 salps. The giant sea bass was once common 

 in southern California, but its numbers 

 have been severely decreased by 

 overfishing. Individuals swim 2-3 m above 

 the substrate, and feed on spiny lobsters, 

 squid, and fishes (Feder et al. 1974). 

 Salema and jack mackerel may form large 

 schools in kelp forests during summer and 

 early fall when the water is warmer. 



4.6 BIRDS AND MAMMALS 



4.6.1 Birds 



4.6.1.1 Introduction . The associa- 

 tion of birds with California kelp forests 

 is poorly known, and is limited to 

 generalized accounts. Due to the paucity 

 of published literature, much of the 

 discussion below will be based on personal 

 conmunications. 



North (1971b) does not include any 

 birds in his list of the kelp bed fauna 

 for southern California and northern Baja 

 California, Mexico. However, he does 

 mention birds as being top carnivores in 

 the kelp community. Davis and Baldridge 



(1980) acknowledged that seabirds often 

 frequent kelp forests. Angell and Balcomb 

 (1982) reported that the edges of Puget 

 Sound, Washington kelp beds are 

 "patrolled" by guillemots, auklets, and 

 pelagic cormorants. Page et al . (1977) 

 characterized the inshore bird assemblage 

 as being made up of loons, grebes, 

 cormorants, scoters, and pigeon 

 guillemots. The only quantitative study 

 of bird-kelp forest association is Hubbs 

 et al. (1970), who documented the diet of 

 Brandt's cormorants. 



Kelp provides three distinct habitats 

 used by birds: 



1. Kelp Forest: Living, attached 

 kelp in association with rocky substrata. 



2. Drift Kelp: Detached kelp that 

 may be found floating far out to sea in 

 the pelagic zone. 



3. Kelp Wrack: Detached kelp 

 deposited on the beach by water motion. 



The discussion below is organized by 

 these habitats. Ashmole (1971) should be 

 consulted for details of the feeding 

 methods of the seabirds described. 



4.6.1.2 Kel p forests . Kelp forests, 

 with their associated invertebrates and 

 fishes, provide a large potential food 

 supply for birds. In addition, a well- 

 developed kelp canopy reduces water 

 motion, serving as a refuge from storms. 

 From the standpoint of bird use, kelp 

 forests can be conveniently divided into 

 three somewhat distinct subhabitats: (1) 

 the surface canopy; (2) the midwater and 

 the bottom substrata beneath the canopy; 

 and (3) the seaward fringe of the forest. 

 The common birds in each subhabitat are 

 listed in Table 10, and are discussed 

 below. 



Surface canopy . A well-developed 

 canopy forms a buoyant mat on which birds 

 may perch. The degree of canopy 

 development is probably the most important 

 factor in determining the numbers and 

 diversity of birds that will be present. 

 Seasonal variations in canopy development 

 dictate the degree to which kelp forests 

 will be utilized by birds. 



Baldridge (pers. comm.) observed 

 large numbers of elegant terns ( Sterna 

 elegans , Figure 23) and Heermann's gulls 



76 



