Nudibranchs are a type of shell fish that loose their shell in their early life. They are recognisable by the “frills” or gills at the back and their snail like antenna at the front.
The Black Doris, or Dendrodoris nigra is the one that is the most plentiful at Henderson Bay, found in the large lagoon pool at the north end of the beach, crawling around on the rock faces or other shaded areas.Â It looks like a black rock, the only thing is that the “black rock” moves! Can grow up to 40mm in length.
The Gem Doris or Dendrodoris denisoni have been found cruising around on the upright coralline alge plants on which it feeds. It has been found in the mid intertidal zone as well as the low intertidal zone. Can grow up to 50mm in length.
The Clown Doris or Ceratosoma amoenum lives in the shallow sub tidal zone (after the low tide zone where the tide never retreats from) and is found on the reef walls underneath seaweed which needs to be pushed aside to find it. You will need a mask and snorkel to find this one. Can grow up to 40mm in length.
Lastly is the Rostanga muscula which is endemic to New Zealand, meaning that it lives here and no where else in the world (like the kiwi). It is very common in the intertidal zone but as it only grows to 20mm in length it is often missed.
Click on each photo below to view more detail.
All photos have been taken at Otaipango – Henderson Bay