Danel Wentzel
P H O T O G R A P H Y
NUDES OF THE BAY
Nudibranchs of False Bay
Discover the tiny, macro world of the Nudibranch species that call False Bay in Cape Town their home.
WHAT ARE NUDIBRANCHS?
Small, colourful and varied, nudibranchs are many diver’s favourite subject matter. Nudibranchs as a group can be found worldwide, but most species are endemic to an area.
Nudibranchs are members of the phylum Mollusca, which is derived from the Latin “mollus”, meaning soft-bodied. A common characteristic of all members of this group. They are part of the order Opisthobranchia, which includes all the sea slugs. All nudibranchs are sea slugs, but not all sea slugs are nudibranchs – they fall in their own order, Nudibranchia.
The word nudibranch is derived from Latin and means “naked gill” – because their gills are on the outside of their bodies. The nudibranchs are the only subgroup with its own subgroup, which contains the four suborders Doridina, Dendronotina, Aeolidina and a group that does not fit into the previous three, the Arminia.
Now that we know what nudibranchs are - let us have a look at some familiar little faces that you may have encountered on your dives in Cape Town.
DORIDINA
Contains more species than the rest combined. Frequently spotted due to their relatively large size and typically flamboyant colours. All Dorids display conspicuous gills and for most the gill structure forms rosettes or circles around the anus.
Cape Dorid
Twin Crown
Fiery Nudibranch
Black Nudibranch
Ghost Nudibranch
Orange Clubbed
DENDRODORIDINA
Typically long and tapered with gills forming a series of appendages. The groups rhinophores are generally fluted or cup-shaped.
Cowled Nudibranch
ARMINIA
A catch-all for species that do not fit into other suborders. An oral veil, also known as a velum, on the head is the only obvious characteristic that Arminids have in common.
Frilled Nudibranch
Gas Flame
Cape Silvertip
AEOLIDINA
Members typically have long tapering bodies, a pair of cephala tentacles on their heads, and clusters or rows of cerata extending down their backs.
Four Colour
Purple Lady
Coral Nudibranch
Orange-Eyed
There are about 80 unique species of Opisthobranchs in False Bay and the Cape Peninsula, of which 67 are nudibranchs. There are plenty of little critters to find underneath the canopy of Cape Town's kelp forests, and they will keep even the most veteraned diver busy for many dives to come.
If you want to have your own comprehensive field guide, I recommend the local book by Guido Zsilavecz called Nudibranchs of the Cape Peninsula and False Bay which you can order directly from him here.
