NO not those kind of nudi photos… Of course. Malapascua is famous for thresher shark diving, and divers from around the world visit Evolution for a very special sunrise dive. However, did you know that Malapascua is also home to an excellent array of macro diving? The Philippines hosts a huge variety of nudibranch species and visitors are often surprised by their size and colour.
To make your slug sightings easier to identify we are collecting nudi sightings from our eagle-eyed staff and a printed copy of nudis from around the island is available in the bar. In the near future you may even be able to complete a PADI Distinctive Speciality course in nudibranchs, as our staff are working with PADI to create a unique diving course available only at Evolution.
What is a nudibranch? The name is often ascribed to any colourful, sluggy creature on the sea floor but actually only refers to a specific group of sea slugs. Sea slugs are all opistobranchs which means the gills are found behind and to the right of the gills. Nudibranchs are a family within the opistobranchs and the Latin name refers to their external lungs; nudi meaning naked and branchia meaning lungs. The Latin origin is why the ch in nudibranch is pronounced with a hard ‘k’. The tree like protrusions sticking out of the slug’s body are its lungs exposed in the water column. Some nudibranchs have external lungs but are able to retract them into their body.
Highly prized by divers because of their vivid colour variations, it is unlikely you’ll have seen these in captivity as they are capable of taking out an entire aquarium tank with the release of poisonous chemicals. This is a clever evolutionary defence called aposematism which could be seen as the opposite of camouflage. Rather than disguise themselves and hide from predators, creatures using this device flaunt overt signals to warn predators away.
Pictured here are two commonly found nudibranch species of Malapascua; the Blue Dragon (Pteraeolidia Ianthina) and Crested Nembrotha (Nembrotha Cristata). The Blue Dragon is a particularly interesting species, getting its vivid colouration from tiny unicellular organisms living within its body just as with clams and coral. For this reason, juvenile Blue Dragons are white in colour. Through a process called endosymbiosis they utilise the nematocysts (stinging cells) from their soft coral prey and reuse them as a defensive mechanism in their own body.
Next time you are here ask our staff about the sea slugs the island has to offer and see how many you can spot.