Distribution, substrate preference and possible host benefits of the tropical polychaete Spirobranchus giganteus on a reef in Bonaire

The Christmas Tree worm, Spirobranchus giganteus, is a sessile polychaete found on coral reefs worldwide. Its larvae display photopositive behavior and use chemicals excreted from live coral as a settlement cue. After settlement, the worm grows in concert with the coral for the remainder of its life. S. giganteus displays variable preference for corals as substrate worldwide. It has been shown that the presence of S. giganteus on corals can lessen the effects of disease and coral bleaching on polyps surrounding the worm’s tube, as well as lessening predation by certain corallivores. Due to its potential to maintain healthy corals, it is important to learn more about the ecological role and distribution of S. giganteus. This study aimed to determine at what depth S. giganteus densities are highest, as well as its preferred coral substrate on the fringing reef surrounding Bonaire, Dutch Caribbean. It also intended to demonstrate that the presence of S. giganteus could lessen the effects of disease and bleaching on the corals on which it lives. Using benthic transects at three different depths at two study sites, it was found that S. giganteus density was highest at shallower depths. The preferred substrate was found to be the boulder star coral, Orbicella annularis. Data regarding the effects of S. giganteus on coral disease and bleaching was too limited to determine any relationship between them, but it is recommended that this relationship be investigated in depth due to its possible role in recovering from coral bleaching

This student research was retrieved from Physis: Journal of Marine Science XIV (Fall 2013)19: 61-68 from CIEE Bonaire.

Back to search results