Mediterranean Zoanthid

Cnidarian

Identification & Biology

• IdentificationA colonial zoanthid that encrusts hard surfaces, forming mats of small, yellow-gold polyps with a ring of short tentacles. The colony grows over rock, gorgonians, and other structures. Old colonies can become massive and mound-like.
• SizeIndividual polyps up to 2 cm diameter. Colonies can grow to over 1 m across and several centimetres thick.
• Social HabitColonial. Slow-growing, with large colonies estimated to be hundreds or even thousands of years old. One of the longest-lived animals in the Mediterranean.
• HabitatDeep rocky walls, overhangs, and cave entrances. Often found encrusting dead gorgonian skeletons.
• Depth15 to 100 m. Most common between 30 and 70 m.
• Feeds OnPlankton and suspended organic particles captured by the polyps.
• DistributionMediterranean Sea and adjacent eastern Atlantic. Present in Maltese waters on deeper reefs.
• DescriptionGerardia savaglia is often called the false black coral because large, old colonies produce a dark, horn-like internal skeleton. It is one of the slowest-growing and potentially longest-lived animals in the sea, with some colonies estimated at over 2,000 years old. It is strictly protected under Annex II of the Barcelona Convention. Any colony encountered on a dive deserves respect as a potentially ancient organism.