uncinata build tubes in kelp laminae by 

 curling the edges of blades and sticking 

 them together. They eat kelp, and may 

 puncture blades with their spines and 

 hooks (North and Schaefer 1964). 



Other crustaceans known to feed on 

 kelp forest seaweeds are various spider 

 crabs (Hines 1982), especially Taliepus 

 nutal li , and the kelp crab Pugettia 

 producta (Figure 20). Although often 

 abundant, their grazing does not appear to 

 have a great effect on plants. 



4.4.4 Predators 



Many species 

 invertebrates inhabit 

 Macrocystis forests, but 

 is known about their 

 dynamic relationships of 

 kelp stands. Table 8 



of predatory 

 or frequent 

 overal 1 , little 

 effects on the 

 organisms within 

 lists the more 



common or larger predators found in kelp 

 forests on the west coast of North 

 America. This list includes only a small 

 subset of species that may be found in 

 many localities. More comprehensive lists 

 can be found in Ricketts et al . (1968), 

 North (1971b), Smith and Carlton (1975), 

 and Morris et al. (1980). 



4.4.4.1 Sea stars (Echinodermata) . 

 Several species of predatory sea stars may 

 be easily located in most kelp forests. 

 The larger species (see Table 8) can be 

 voracious predators of other invertebrate 

 species, especially favoring sea urchins, 

 gastropods, and chitons. Intertidally, 

 sea stars of the genus Pisaster may 

 directly affect the species composition 

 and may allow successional events in some 

 communities (Paine 1974). They may 

 preferentially consume mussels, the 

 competitively dominant species on some 



Table 8. Common invertebrate predators found in Macrocystis forests. 



Species 



Common name 1 



Leather star 



PHYLUM ECHINODERMATA 



Dermasterias 

 imbricata 



Astrometis sertul if era 

 Pisaster ochraceus Ochre star 

 £. giganteus 

 P_. brevispinus 



Pycnopodia 

 helianthoides 



Patiria miniata 



PHYLUM MOLLUSCA 

 Navanax inermis 



Pleurobranchaea 

 cal ifornica 



Loligo opalescens 



Sunflower star 



Bat star 



Common squid, sea 

 avian, calamari 



Predatory effects 



Will eat the purple sea urchin S. purpuratus , 

 anemones, and corals. 



Occasionally feeds on chitons and sea urchins. 



Eats snails, limpets, chitons, and barnacles. 



Same as above. 



Same as above. 



Commonly eats sea urchins, snails, chitons, 

 crabs, and other sea stars. 



May eat smal 1 Lytechinus anemesus . 



Eats other opi sthobranchs. 



Will eat Navanax , anemones, and other members 

 of its own species. 



Feeds mainly on shrimp-like crustaceans. 



(continued] 

 66 



