| This study compares the reproductive biology and ecology of three sympatric species of cold-water corals from central California: the solitary corals Balanophyllia elegans and Paracyathus stearnsii, and the colonial coral Astrangia lajollaensis. It deals particularly with sexual reproduction and the reproductive cycles of the three species, with the population dynamics of B. elegans, and with asexual reproduction and colony growth in A. lajollaensis.;Balanophyllia elegans receives particular attention: disjunct gametogenesis, timing of planula release, types of planulas, planula dispersal, larval and juvenile survivorship, and life history patterns. Broadcasting and brooding are discussed with respect to polyp size and skeletal design in scleractinians in general, and B. elegans and P. stearnsii in particular. The advantages of both sexual and asexual reproduction for A. lajollaensis are discussed. A model for colony growth in this species is presented. Asexual reproduction in A. lajollaensis is then compared to that of some actinians.;The animals were studied in a kelp forest at the Hopkins Marine Life Refuge (HMLR), Pacific Grove, California, and were collected for anatomical and histological examination of their gonads. Their reproductive activity was monitored in the laboratory. Permanent quadrats were photographically monitored for population changes, larval recruitment and response of corals to specific manipulations.;Balanophyllia elegans is dioecious, reproduces only sexually, and broods its embryos. Males are ripe in late summer, but oocytes and embryos ((TURN)40 per female) are found throughout the year. Large, crawling benthic, planulas (3-5 mm) are released mainly in the winter. Mortality rates are low for planulas and high for juveniles. At HMLR, B. elegans has early sexual maturation (at 1-2 yrs.), repeated reproduction thereafter, and short life span (6.5-11 yrs.).;Paracyathus stearnsii is also dioecious. It produces a large number of small eggs, and it has gametogenic synchrony, broadcast spawning, and external development. Sexual recruitment has not been recorded in the field. Females and males at HMLR spawn between February and April. A small planktonic planula ((TURN)150 (mu)m) is produced. P. stearnsii reproduces only sexually but is capable, as well, of significant regeneration. . . . (Author's abstract exceeds stipulated maximum length. Discontinued here with permission of school.) UMI. |
