Gammaridean Amphipoda of the Rocky 

 Intertidal of California: Monterey Bay to 

 La Jolla 



Introduction 



The Californian rocky intertidal, with its rich flora and its exposure 

 to seas of normal salinity, supports a diverse and numerically abundant 

 amphipodan fauna. Gammaridean Amphipoda are the most abundant 

 of the macroscopic Crustacea in this zone; their density exceeds that 

 of the larger Decapoda and those companion orders of similar body 

 size such as Isopoda, Cumacea, and perhaps Tanaidacea. However, 

 the latter organisms are very small in size and may be lost in sample 

 processing methods using meshes of 0.5 mm. openings. The smaller 

 Copepoda and Ostracoda, of course, are far more abundant than 

 Amphipoda. 



Despite their known frequency, intertidal Amphipoda of California 

 have not been studied intensively, although Shoemaker in his broad 

 attack on world amphipod problems has touched on them frequently 

 and has made important contributions in modernizing the nomencla- 

 ture. The present paper describes the amphipods collected in a survey 

 of the southern half of California from Monterey Bay to La Jolla, a 

 distance of nearly 5 degrees of latitude or roughly 600 kilometers. The 

 survey is based on more than 360 samples, many of which are crudely 

 quantitative, taken at 7 major collecting sites. 



Literature 



Short systematic reviews of Californian Amphipoda appeared in 

 "Between Pacific Tides" by Ricketts and Calvin (late editions edited 

 by Joel W. Hedgpeth) and in the second edition of Light's "Intertidal 

 Invertebrates of the Central Californian Coast" (edited by Ralph I. 

 Smith and others). Nomenclaturally, those presentations are modern- 

 ized herein (Appendix II) but revised keys await continued explora- 

 tion in northern California. 



The literature of Californian Amphipoda must include that of 

 Washington (Puget Sound, Friday Harbor), Oregon, and Baja Cali- 



1 



