Ecology and Gametogenic Biology of the Genus Umbellula (Pennatulacea) in the North Atlantic Ocean

Abstract

AbstractFour putative species of the seapen genus Umbellula, U. lindahli, U. thomsonii, U. durissima and U. monocephalus, are found at bathyal and abyssal depths in the Porcupine Seabight and Abyssal Plain in the NE Atlantic Ocean and at bathyal depths off the Bahamas. The most common species, U. lindahli, has a cosmopolitan distribution in the world ocean. In situ observations, from bathyal depths in the Bahamas, of the posture of U. lindahli show that the polyps are spread out to maximize particle capture from the water column. In addition, the individuals of U. lindahli from the Bahamas suggest that the tentacles are cropped by a predator, but there is no evidence of predation in the NE Atlantic specimens. Reproduction in U. lindahli is typical of that previously observed in pennatulids. Fecundity is high, although most of the oocytes present are previtellogenic with only a few developing through to maximum size at any one time. Some specimens of U. lindahli appear to be infested with a small flatworm.