Berghia Azurée

Overview

Berghia coerulescens is a striking nudibranch belonging to the family Aeolidiidae. It is widely recognized as the type species of the genus Berghia and is primarily found in temperate and warm waters across the Mediterranean Sea and the eastern Atlantic Ocean.

Distribution & habitat

This species is native to the Mediterranean and the eastern Atlantic, with a range extending from the coasts of Brittany down to the Canary Islands. It typically inhabits shallow rocky environments, often dwelling among algae or near its primary food sources at depths ranging from the surface down to 30 meters.

Appearance

This nudibranch features an elongated, white or opaque bluish body adorned with numerous cerata—finger-like dorsal projections used for respiration and defense. The cerata are characteristically bright blue with a distinct yellow ring near the tip. A key identifying feature is a pair of elongated orange marks located on the head between the rhinophores and the oral tentacles. Its rhinophores are club-shaped and feature small tubercles or lamellae on their posterior side.

Biology & behavior

Berghia coerulescens is a solitary, nocturnal creature that moves with a graceful, gliding motion using its muscular foot. Like all nudibranchs, it is a hermaphrodite, meaning each individual possesses both male and female reproductive organs. During reproduction, they engage in mutual fertilization and deposit spiral-shaped egg masses onto hard surfaces.

Feeding

This species is a specialized predator that feeds primarily on sea anemones, particularly those belonging to the genera Aiptasia and Sagartia.