Detection, pursuit, and overgrowth of tropical gorgonians by milleporid hydrocorals: perseus and medusa revisited.

Encounters leading to competitive interactions between colonies on coral reefs are to some extent accidents of patterns of recruitment and growth. In contrast, colonies of Millepora spp. actively detect nearby arborescent gorgonians and subsequently redirect growth in order to contact and overgrow them. Detection is dependent on water flow over the two colonies.

Hurricane Allen's Impact on Jamaican Coral Reefs.

Coral reefs of north Jamaica, normally sheltered, were severely damaged by Hurricane Allen, the strongest Caribbean hurricane of this century. Immediate studies were made at Discovery Bay, where reef populations were already known in some detail. Data are presented to show how damage varied with the position and orientation of the substraturn and with the shape, size, and mechanical properties of exposed organisms. Data collected over succeeding weeks showed striking differences in the ability of organisms to heal and survive.