On your next seaside holiday, a miniature world of magic awaits – if you know where to look, says HELEN WALNE
Slugs. What invariably springs to mind are chubby, dull, slimy creatures gnawing at newly planted lettuces or trailing their way down doors. But in the ocean, sea slugs – or nudibranchs – are some of the most colourful, flamboyant animals on Earth and have garnered fans around the world – Californians even celebrate International Nudibranch Day on 29 October.
Some nudibranchs resemble psychedelic sheep; others Rio Carnival dancers. There are frilly ones, crystalline ones, shaggy ones and others that would give Lady Gaga a run for her money. Nudibranchs (pronounced ‘noodi branks’) are found in seas all over the globe, from Scotland to
São Tomé, from Iceland to Indonesia. The name is derived from the Latin nudus (naked) and Greek brankhia (gills), due to the slug’s lack of a shell (unlike other marine gastropod molluscs) and the gills being found in a rosette on the outside of the body.
It’s estimated there are about 500 species in SA, with this figure expected to grow as previously undiscovered or unidentified ones turn up. Nudibranchs are found at depth, but also in shallow water, on reefs and even in tidal pools, which means you don’t have to be Aquaman to spot them. All you need is a mask and snorkel and a pair of eagle eyes, as many are just a few millimetres long.
• Take it slowly. Most are tiny, so thoroughly scanning just a small area (the wall of a tidal pool) may deliver results.
• Get to know their diet. Many nudibranchs are very specific about what they eat, so familiarise yourself with the different food sources.
• Look out for their eggs. You’ll often find a nudi near an elongated egg ribbon (pictured below, a fiery nudibranch laying eggs).