SEXUAL REPRODUCTION OF THE ALCYONACEAN CORAL LOBOPHYTUM PAUCIFLORUM IN SOUTHERN TAIWAN

Abstract

Sexual reproduction of the alcyonacean octocoral Lobophytum pauciflorum (Ehrenberg) in Nanwan Bay, southern Taiwan was studied by histological examinations of gonad development on monthly samples collected from tagged colonies between March 2001 and November 2002. A sample of 15 aggregations of L. pauciflorum in an area of 10 × 30 m was also examined in July 2002 to determine reproductive traits. Lobophytum pauciflorum is a gonochoric broadcast spawner and the sex ratio of the population is 1:1. Lobophytum pauciflorum often forms aggregations in which all of the colonies have the same sex. This suggests that the colonies in an aggrega tion are likely formed by asexual fission. Most (>50%) of the colonies in the female and male aggregations had gonads when their diameters were 10–15 and 5–10 cm, respectively. The average maximum fecundity was 16 eggs polyp −1 . Mature eggs were 400–870 µm in diameter. Oogenesis and spermatogenesis took about 12 mo. Spawning occurred from July–September during late summer to early autumn. This spawning season is consistent with the environmental conditions such as warmer water temperatures and new bare substrate created by typhoon disturbances that favor the survival and settlement of coral larvae.