. Bulletin. Science; Natural history; Natural history. SURVEY OF SOUTHERN CALIFORNIA ASCIDIANS 123. Fig. 1. Southern California Channel Island Collection Sites. Arrows around islands and rocks indicate collecting sites. east, south and west sides of each of the islands. In addition to the Channel Islands, sites on Richardson Rock, Wilson Rock, Begg Rock, the Coronado Is- lands and Cortez Bank were surveyed to a depth of about 30 m with the aid of SCUBA (Fig. 1). The period of study extended from 17 August 1972 to 11 February 1979. De- tailed records of the dates and locations of the collection
. Bulletin. Science; Natural history; Natural history. SURVEY OF SOUTHERN CALIFORNIA ASCIDIANS 123. Fig. 1. Southern California Channel Island Collection Sites. Arrows around islands and rocks indicate collecting sites. east, south and west sides of each of the islands. In addition to the Channel Islands, sites on Richardson Rock, Wilson Rock, Begg Rock, the Coronado Is- lands and Cortez Bank were surveyed to a depth of about 30 m with the aid of SCUBA (Fig. 1). The period of study extended from 17 August 1972 to 11 February 1979. De- tailed records of the dates and locations of the collection sites are maintained at Pacific Bio-Marine Labs, Inc. Specimens collected were placed in 15% magnesium sulfate sea water along with a few crystals of menthol for 12 to 16 h to narcotize them. They were then transferred to 5% sea water formalin. Zooids were examined under a dissecting microscope and identifications were made using Van Name, 1945; Berrill and Abbott, 1949; and Abbott, 1975. Results and Discussion The mainland, island, and bank distribution of each species of ascidian col- lected is listed in Table 1. This table also indicates those species which brood their tadpoles (viviparous species) and those which release their gametes into the water (oviparous species). This distinction in mode of reproduction is noted be- cause the Channel Islands appear to have a higher percentage of viviparous species when compared with the ascidian biota of the mainland (Table 2). No oviparous species were found on the three rocks visited. This suggests that the short larval period of the viviparous ascidians is essential to the maintenance of these species at the isolated island collection sites where active current movement is observed. Viviparous ascidians usually produce tadpoles which are able to settle and metamorphose within minutes to a few hours after being released from. Please note that these images are extracted from scanned page images that may have been digitally enhanced
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