About Alcyonium acaule Marion, 1878
Alcyonium acaule, commonly called Mediterranean sea-finger, is a colonial soft coral that forms clumps of fleshy, finger-like lobes. It can display colors ranging from yellow, pink, and brown-red to brown-orange. Colonies reach a maximum height of 20 cm. The entire surface of the body, from the foot up to the top of the lobes, is completely covered by whitish polyps. Like all soft corals, this species uses its hydrostatic skeleton to maintain and adjust its body posture. This species is endemic to the Mediterranean Sea, but its distribution extends slightly beyond this region along the Atlantic coasts of Portugal and Spain. It is typically found at depths between 12 and 135 meters. Alcyonium acaule is a sciophilous organism; it avoids places exposed to unfiltered light, and prefers shaded locations such as overhangs or caves. In the Mediterranean Sea, Alcyonium acaule frequently forms dense agglomerations, most often in association with the yellow cluster anemone Parazoanthus axinellae. These biodiverse habitats host other organisms including suspension feeders such as sponges, cnidarians, bryozoans and tunicates, and the underlying rock is encrusted with coralline algae. These organisms compete for available space. During a two-year research study, a number of small Alcyonium acaule colonies disappeared, and very little overall colony growth occurred. Many colonies showed reduced feeding activity during the summer, with up to ninety percent of colonies becoming dormant.
