Meet Parma kermadecensis, commonly known as the Kermadec scalyfin. As its scientific name suggests, it is a Kermadec endemic, meaning it is found only here (although two individuals have been seen at the Poor Knights). The Kermadec scalyfin is related to the black angelfish from around New Zealand.
Not many of the fish species here are endemic as the islands haven’t been around long enough for most fish to evolve into new species. Fish-wise these islands are a great example of long distance dispersal, with tiny fish larvae that start out life as plankton getting swept here by currents.
The three photos here are all of the Kermadec scalyfin, and show the different colourings that the fish have at different stages of their life. The picture above is of an adult, which grow to about 25-30 centimetres long. Next up is a picture of a sub-adult, about 12 centimetres long.
Finally, this is an 8 centimetres long juvenile.
I have to confess that as a non fish biologist I would have said those were three different species! But that’s one of the challenges facing the fish scientists on this expedition – it’s not enough to know just what an adult fish looks like. They also have to be familiar with all the different life stages. No wonder there are sometimes heated discussions out on the back deck at fish sorting time!