Marine researchers from Te Herenga Waka—Victoria University of Wellington have discovered a species of sea squirt that is thought to be new to science.
The sea squirt was found off Rakiura Stewart Island while the researchers were exploring marine communities that live on the area’s deep-water reefs.
“We were off Port Pegasus at the southern end of Rakiura and we could see all these really unusual ‘egg’ shapes on the seafloor. Closer inspection revealed they were large, 30 cm tall sea squirts that we haven’t found in any other part of Aotearoa,” said Professor James Bell, a marine biologist at the university.
Marine ecologist Mike Page, an emeritus scientist from the National Institute of Water and Atmospheric Research, confirmed the sea squirt is likely to be a new species that is yet to be named.
Sea squirts, also known as ascidians, play a key role in maintaining water quality. They are filter feeders—creatures that feed on nutrients in the water column.
“Unusually, sea squirts dominated the marine communities on the deep-water reefs that we explored off Stewart Island. We typically find sponges are the dominant player on deep-water reefs in other parts of the country,” said Professor Bell.
The new species of sea squirt was found at a depth of 115 metres.
“The water off Stewart Island was really clear down at this depth. This probably reflects the fact there are no major rivers draining into the sea and there are still large areas of native forest on the island.”
Video footage of the reefs shows many different species of sea squirt, varying in colour from bright white to pinks, blues, and yellows.
The footage was taken using a remotely operated vehicle (ROV) that can film in waters of more than 100 m deep.
“Finding this sea squirt is a reminder that we still have so much to learn about the rich diversity of life in the ocean. It’s also a reminder of the need to ensure we protect our marine environment and the unique species it supports,” said Professor Bell.
The ROV used by the researchers to collect video footage was purchased with funding from the George Mason Charitable Trust.
