Studies of artificial substrate properties affecting fish attrac- 

 tion and ecological succession in southern California were reported 

 by Carlisle, Turner, and Ebert (1964), Turner, Ebert, and Given 

 (1969), and Fager (1971). Carlisle, Turner, and Ebert (1964) con- 

 ducted visual surveys of biota in bottom areas before and after 

 artificial reef establishment, noting that fishes were attracted 

 within hours of reef construction. Carlisle, Turner, and Ebert 

 (1964) also made ecological observations at a number of offshore oil 

 installations, including Rincon Island. They concluded that these 

 sites exhibited similar attractions for fish and, more generally, 

 that "habitat changes brought about by establishing offshore oil- 

 drilling installations were generally beneficial to the flora and 

 fauna." 



Results of a 4-year study of various aspects of manmade reef 

 ecosystems and optimal materials for reef construction, conducted by 

 the California Department of Fish and Game, were published by Turner, 

 Ebert, and Given (1969). Of four types of reef construction mate- 

 rials evaluated, quarry rock was judged optimal on the basis of 

 practicalities of cost and handling, fish attraction (although con- 

 crete shelters were better in this regard) , and minimal sediment 

 disturbance. More than 200 invertebrate taxa were recorded during 

 the study. Succession on the newly established reefs proceeded from 

 an initial barnacle-hydroid phase, into a mollusk-polychaete assem- 

 blage, to an ascidian-sponge stage, and finally a stage characterized 

 by the presence of abundant encrusting ectoprocts (moss animals) . 

 Aggregate anemones, gorgonians, and stony corals appeared in later 

 stages. Approximately 5 years was required for successional change 

 to cease on these artificial reefs. 



2. Previous Studies of Rincon Island . 



The California Department of Fish and Game biologists made an 

 initial survey of Rincon Island in July 1958, 18 months after con- 

 struction of the island began (Carlisle, Turner, and Ebert, 1964). 

 They conducted 26 observational dives over the period, August 1958 to 

 December 1960. Despite many fluctuations, possibly due to water 

 clarity or incoming year classes of fishes, an overall upward trend 

 in fish populations was observed. Toward the end of the survey 

 period the biota of the island had the appearance of "a well-balanced 

 animal community." Fifty-three species of fish belonging to 44 

 genera in 22 families were observed during this study. About 97 

 percent of the fish fauna belonged to the following groups: silver- 

 side, (Atherinidaej , surfperch (Emhiotocidae) , sea bass (Serranidae) , 

 damselfish (Pomocentridae) , rockfish (Scorpaenidae) , and halfmoon 

 (Scorpidae) . The biologists noted populations of large, active 

 fishes in turbulent waters along the west (seaward) side of the 

 island, sedentary forms such as sculpin (Cottidae) , and rockfish 

 occupying spaces among the rocks, and the young of many species 

 (especially kelp bass (Paralabrax clathratus) , blacksmith (Chromis 



