LASKER, H.R.*; GUTIERREZ-RODRIGUEZ, C.; University at Buffalo; University at Buffalo: Fertilization and local gamete dispersion in a surface brooding gorgonian

Colonies of the Caribbean gorgonian Pseudopterogorgia elisabethae release unfertilized eggs that are retained on the colony surface where they are fertilized and develop into planulae. On San Salvador, Bahamas spawning starts in the week following the new moon in November and December. Although synchronous, not all colonies release gametes in the same month or on the same day. Egg release in Dec. 2002 occurred over 6 d with spawning by any one colony being limited to 1-3 d. With the exception of the first and last day of the spawning period, fertilization rates were high, often >90%. In aggregate eggs collected in December 2001 had fertilization rates of 71%. The number of colonies in close proximity to a female was not correlated with fertilization rate. However, eggs are probably fertilized by nearby males. Microsatellite markers were used to determine the paternity of 187 planulae collected from 4 females during Nov. 1999. All of the planulae could be assigned a father within the study area and distance between the mother colony and most likely father ranged from 1.4 to 10.5 m. Variation in parentage between days suggests that parentage was strongly influenced by current patterns. The results suggest that surface brooding is a highly efficient mechanism for “harvesting” sperm released upstream of female colonies and that sperm dispersal alone generates only low levels of gene flow in this gorgonian coral.