Science Centres: Aquatic Biodiversity and Biosecurity

This specimen of Paragorgia arborea (a ‘bubblegum’ octocoral) has a trunk 42 cm in diameter, was probably at least 7 m high, and may be 300–500 years old.

The count of octocoral species in New Zealand waters keeps climbing. Octocoral habitats range from the low tide mark to the deep sea. They are recognised by their polyps, which typically have eight tentacles.

New Zealand’s fauna is proving to be among the richest in the world. Recent work has pushed the number of different octocoral species in New Zealand’s Exclusive Economic Zone (EEZ) up to 243 species, only 48 of which have been named as yet. This work has also doubled the known number of bubblegum corals in the world. More than half of these are new species and are found only in New Zealand’s EEZ. Bubblegum corals are some of the most impressive-looking octocorals, and include the largest seafloor invertebrate species on the planet, Paragorgia arborea.

The work also developed a method of estimating the age of ‘bamboo’-type octocorals, which could not previously be accurately dated because their growth rings are extremely close together.

This kind of information is critical to ecosystem-based management of seamounts, and contributes to the New Zealand Biodiversity Strategy objective of improving our knowledge of marine ecosystems.