A team of marine scientists has uncovered what appears to be a previously unknown species of sea squirt during a deep-sea expedition off Port Pegasus, near the southern tip of Rakiura (Stewart Island) in New Zealand. The discovery was made while exploring deep-water reef ecosystems at depths of around 115 meters using a remotely operated vehicle (ROV).
Led by researchers from Te Herenga Waka – Victoria University of Wellington, the team recorded footage revealing large, egg-shaped organisms, some measuring up to 30 centimeters tall, clustered along the seafloor. These sea squirts exhibited an unusual range of vivid coloration, including white, pink, yellow, and blue—a rare trait for species found in such deep and lightless marine environments.
Identifying a Unique Deep-Sea Species
Sea squirts, or ascidians, are marine invertebrates that typically attach to underwater surfaces such as rocks, piers, and reefs. While some species are known for their translucent bodies or simple colonial forms, the newly discovered variety stands apart due to its size, shape, and pigmentation. According to Professor James Bell, the principal marine biologist on the project, the sea squirts were visually striking: “We were off Port Pegasus at the southern end of Rakiura, and we could see all these really unusual ‘egg’ shapes on the seafloor,” he said. “Closer inspection revealed they were large, 30 cm tall sea squirts that we haven’t found in any other part of Aotearoa.”
The exact classification of the species will require further analysis, including DNA sequencing and comparative morphological studies, but initial observations suggest that this discovery represents a distinct addition to the ascidian family, possibly endemic to this specific marine region.
Environmental and Ecological Importance
Sea squirts play a vital role in marine ecosystems as filter feeders, helping to maintain water quality by drawing in water through their siphons and filtering out organic particles, plankton, and other microscopic matter. In doing so, they contribute to the nutrient cycling of reef environments and provide habitat stability for other marine organisms.
The presence of such a species in the relatively untouched waters off Rakiura is significant. These ecosystems are known for their biodiversity and serve as indicators of environmental health. The discovery also highlights the continued importance of deep-sea exploration, particularly in temperate Southern Hemisphere marine environments, which remain underrepresented in global marine biodiversity surveys.
Potential Benefits Beyond the Ocean
Beyond their ecological function, sea squirts have gained scientific interest for their biomedical potential. Studies cited by the article point to research at Stanford Medicine, where sea squirt biology is being investigated for insights into the human immune system. Additionally, a recent report in Neuroscience News suggests that certain compounds found in sea squirts might hold promise in anti-aging treatments, potentially by interacting with cellular pathways involved in degeneration.
The implications of these findings are twofold: they point to both the biotechnological value of marine biodiversity and the urgent need to protect habitats where such organisms exist. The discovery of a previously unknown species in New Zealand waters underscores how little is still known about deep-sea life—and how many potential breakthroughs might be lying undisturbed in similar unexplored environments.
Deep-Sea Discoveries in a Changing Ocean
While this discovery provides a hopeful example of biodiversity in action, it comes at a time when climate change is disrupting marine ecosystems globally. According to research from the Columbia Climate School, sea squirt populations in sensitive regions such as Antarctica are already experiencing declines due to rising sea temperatures, acidification, and extreme weather patterns. These stressors can affect reproductive cycles, larval dispersal, and habitat availability—ultimately threatening entire marine food webs.
In this context, the find off Rakiura offers both optimism and urgency. “It’s also a reminder of the need to ensure we protect our marine environment and the unique species it supports,” said Professor Bell. His team views the discovery not just as a scientific success but as a conservation message, calling attention to the fragile, often overlooked ecosystems that exist far below the ocean surface.
The researchers emphasize that their work is ongoing. Additional analysis and formal classification of the species are expected in upcoming publications, and further ROV expeditions may yet reveal other unknown organisms within the area.
