Larval development and settlement behavior of the gorgonian coral Plexaura kuna (Lasker, Kim and Coffroth)

Larval development rate and behavior are described for the broadcast spawning Caribbean gorgonian Plexaura kuna (Lasker, Kim and Coffroth). Cell division commenced 4 h after fertilization. Embryos developed into swimming planulae as early as 36 after the first cell division. Planulae tended to remain on the bottom of experimental chambers and become attached after several days. Position of planulae in 50 cm tall cylinders was dependent on age and lighting with the greatest tendency to sink in the light and 6 days after spawning. When appropriate substratum was provided, significant settlement occurred after 4 days. Planulae were more likely to settle when incubated with substrata entrusted with coralline algae than with bare coral skeleton and when exposed to light than when in darkness. Planulae formed firm attachments to the substratum after 4 to 8 days, suggesting a dispersal potential on the scale of tens of km. In the absence of appropriate substrata, settlement was delayed for up to 3 weeks.