The pink sea slug is a small mollusk, more specifically a nudibranch. In less scientific terms, the pink sea slug is a sea slug that measures about a few inches, 1.2 to 2 inches at most. It has an elongated body that tapers to a point at the rear.
Bigger and ringed! A close-up on the rhinophores of the pink sea slug !
A multitude of protrusions rise from the back of the pink sea slug and undulate with the current. However, navigating the terminology used to describe these protrusions is not easy: dorsal papillae, cerata, or dorsal appendages! These dorsal protrusions are simply the gills of the pink sea slug, allowing it to breathe. Additionally, this multitude of dorsal protrusions characterizes the suborder of Eolid nudibranchs, to which the pink sea slug belongs.
A pair of protrusions located on the head of the pink sea slug serves a special function! Larger and ringed, these protrusions are called rhinophores and act as the sensory organs of the pink sea slug.
As its name suggests, the pink sea slug has a slightly translucent purple coloration. Depending on the lighting, you can see the organs of the pink sea slug through its body ! Furthermore, all its protrusions are entirely purple, including the tips !
Geographic range
The pink sea slug is found in the Mediterranean sea, where it is widely distributed along the French coasts. It is also found in the eastern waters of the Atlantic ocean.
The pink sea slug can be observed from the surface to depths of about 165 feet.
Habitat
The pink sea slug lives on bushy hydroid colonies, which it feeds on.
Diet
The pink sea slug feeds on hydroids, small animals belonging to the phylum Cnidaria that live in colonies. These hydroid colonies appear as branched small shrubs with numerous filaments.
Watch the pink sea slug laying eggs !
A pink sea slug on a colony of hydroids shaped like small shrubs !
The pink sea slug (Flabellina affinis)
Reproduction
The pink sea slug is a hermaphroditic nudibranch species, meaning an individual can produce both male and female gametes.
The female lays pink eggs, wrapping them around the branches of hydroids. Just a week later, the eggs hatch into small larvae.
Did you know ?
Be careful not to confuse the pink sea slug with other similar sea slug species found in the Mediterranean. However, a few color details distinguish them !
the pink sea slug (Flabellina affinis): rhinophores are ringed and the tips of the protrusions are purple.
the purple coryphelle (Flabellina pedata): rhinophores are smooth and the tips of the protrusions are white.
the ischia sea slug (Flabellina ischitana): rhinophores are ringed with white tips. The dorsal protrusions are orange with white tips. This species is less likely to be confused with the pink sea slug !
Tips for observing
The Mediterranean seabeds host significant biodiversity that requires special attention ! During your dives, take the time to linger and carefully scrutinize the seabed, and you’ll reveal abundant marine life before your eyes !
Observe through transparency, in a darker color, the digestive system of the pink sea slug with its many branches !
For spotting the pink sea slug, a dive light will be an additional asset to highlight the fluorescent purple color of this small nudibranch! Additionally, you should be extra cautious around hydroid colonies that the pink sea slug feeds on—those that resemble small shrubs—since some individuals might not be far away !
