Red Coral

• GeneralIts red skeleton has been used in jewellery since antiquity; it grows less than 1 mm a year.
• biologíaIt grows only a few millimetres a year, so a colony of moderate size may be several decades or even centuries old.
• Its deep red skeleton makes it unique among octocorals: as well as the calcified sclerites they all have, it produces a fully calcified internal axis, and that is the red coral of the jewellery trade.
• It grows astonishingly slowly, at around 0.23 millimetres a year, and can live for more than a century. That combination makes it especially vulnerable to harvesting.
• It has been harvested since antiquity. The fishery peaked in the nineteenth century, when a heavy wooden cross hung with nets — the St Andrew's cross — was dragged along the bottom to entangle and tear off the colonies.
• No intact shallow-water population is known today. The discovery in 2010 of an unexplored cave in Corsica with a hundred times more biomass than anywhere else forced a rethink of what its natural state had been: before exploitation it lived at high densities and with many century-old colonies even in shallow water.
• In Portugal it was harvested between the thirteenth and eighteenth centuries until the fishery collapsed, and it went unrecorded for 300 years. It reappeared recently between 60 and 100 m, and poaching came with it: tens of kilos a day.
• It is listed in Annex V of the Habitats Directive and in the Barcelona and Bern conventions.

Habitat and environment

Rocky bottoms and caves of the Mediterranean (30-200 m)

Sexual maturity

First breeding between 7 and 10 years old

Sources consulted: Linneo (1758); Lista Roja de la UICN (Otero et al., 2017); Boavida et al. (2016), PLOS ONE; Garrabou et al. (2017), Scientific Reports