Grooved Brain Coral

• Unlike most stony corals, its polyps are fused into shared grooves that let them pass food and nutrients between one another.
• It eats zooplankton and bacteria, supplemented with nutrients from symbiotic zooxanthellae.
• A colony takes some 250 years to reach a metre across.
• Its surface is a labyrinth of winding grooves and ridges reminiscent of the cerebral cortex, hence the name.
• It grows a few millimetres a year, so a two-metre head is centuries old.
• That slowness turns it into a climate archive: its annual bands make it possible to reconstruct sea temperature and conditions in the Caribbean across centuries.
• And it is also its undoing: it cannot recolonise the reef at the speed at which bleaching, hurricanes and disease destroy it.
• The grooves are not decorative: they channel mucus and sediment out of the colony, which allows it to keep itself clean in turbid waters.
• It is one of the species affected by stony coral tissue loss disease, which has been spreading through the Caribbean since 2014 and kills centuries-old colonies in weeks.

Skeleton type

Invertebrate - external calcareous skeleton (polyp colony)

Habitat & environment

Coral reefs of the Caribbean, the Bahamas, southern Florida and Bermuda, at depths of 1-30 m

Birth weight

Microscopic planula larva after fertilisation

Size at birth

Microscopic planula larva after fertilisation

Sexual maturity

25 years or more to reach breeding maturity

Gestation / incubation

13 hours for the planula larva to swim to the bottom and settle after spawning

Litter / clutch size

At least 6 mass-spawning events a year, among the highest rates documented in any Caribbean coral

Sources consulted: OceanHero; University of Wisconsin-La Crosse (bioweb); ADS/Harvard (reproductive biology study); Animal Diversity Web; Cephalopod Page; Discover Magazine; SeaLifeBase; Scientific Reports (outplanting study)