The Colourful World of Nudibranchs!

This season we´ve seen lots of nudibranchs! Often we find little lilac nudibranchs at the Palma Wrecks and El Sec, this season we´ve also seen large yellow nudibranchs (like the one above taken by Dan, one of our divers who completed his Underwater Photography Speciality course with us) and bright purple and blue nudibranchs at Calo des Monjo.

FACTS:

Nudibranchs are small, very colourful marine animals that look a little bit like a brightly coloured slug with frills. It is thought that nudibranchs and sea slugs once had shells which have been lost through evolution and has helped to cause such diversely coloured species.

They breathe through a bushy branchial plume on their backs rather than using gills. They are bilaterally symmetrical and when fully grown some species can be from 20-600 mm long.

All nudibranchs are hermaphrodites with both male and female reproductive organs however they are rarely able to fertilise themselves.

Nudibranchs are carnivorous feeding on sponges, barnacles and sometimes anemones. Some species are cannibals and may eat other sea slugs or even their own species. Nudibranchs have cephalic tentacles on their heads, which are sensitive to touch, taste, and smell and they have a club-shaped rhinophores usually on their back to detect odors.

The primary defence mechanism for most nudibranchs is its ability to camouflague itself with the surrounding aquatic environment. Some species of nudibranch however have intense bright colours which act as a warning to others, rather like a wasp or bee. They are also able to release a really strong, sour liquid from their skin to protect themselves.

Some nudibranchs can store the stinging cells of other animals they eat in their bodies and use this as an extra defence mechanism. Other species are able to store choloplasts from plants and use them to photosynthesise food for themselves.