From 5-7 May in Sydney, Australia, scientists, First Nations people, local communities, civil society organizations, and government representatives will come together to present and discuss the existing ecological, cultural, and commercial values of the Lord Howe Rise and South Tasman Sea region at the research symposium: ‘A volcanic lost world’.
Stretching almost 2,800 kilometers from the central Coral Sea to the Challenger Plateau, west of New Zealand, the Lord Howe Rise forms a vast deep-sea plateau in the southwest Pacific. Picture a colossal, submerged landscape: a hidden mountain range beneath the sea where life of all kinds converges. Pelagic fish school above, migratory predators pass through, seabirds circle the surface waters, and deep-sea communities thrive along its slopes, extending all the way to the abyssal seafloor.
The region is an important breeding ground and migration corridor for a large number of species. Humpback and southern right whales gather to rest in the waters below as they journey between their feeding and breeding grounds. Seamounts in the region also act as navigational landmarks, guiding species such as mature female tiger sharks as they migrate. The region is further recognised for containing areas of cultural importance to First Nations. These are places where stewardship must be incorporated into future management and conservation efforts to safeguard both the natural ecosystems and the rich cultural heritage of the Lord Howe Rise and South Tasman Sea.
While much about this vast underwater world is yet to be discovered, we already know that its deep ocean hosts vulnerable marine ecosystems characterised by species of extraordinary longevity, such as stony corals, black corals and other deep-sea organisms. In the Southwest Pacific, stony coral reefs and patches formed by Solenosmilia variabilis are hundreds to thousands of years old, while black coral colonies live for millenia, making them amongst the oldest living inhabitants of the region – and the Earth itself.
Among these ancient ecosystems live deep-sea species of commercial interest, including populations of orange roughy. The roughy is an ancient fish, capable of living up to 250 years. These fish gather to spawn on seamounts: the same seamounts that host fragile ecosystems of deep-sea corals.
When trawlers sweep through to catch orange roughy aggregations during spawning, threatening the species’ ability to reproduce and maintain healthy population levels, destruction comes swiftly. Coral habitats are devastated in an instant, yet take centuries to recover. Trawling these delicate ecosystems is like tearing pages from Earth’s most ancient history book. Once lost, they cannot be rewritten within our lifetimes.
In 2024, these concerns were once again realized when a New Zealand-flagged bottom trawler operating in the region dragged up 37 kilograms of deep-sea coral. This latest incident underscored the continuing impacts of bottom trawling on vulnerable marine ecosystems in the region, and prompted the South Pacific Regional Fisheries Management Organisation (SPRFMO) to temporarily close the immediate area to prevent further damage to coral communities and other vulnerable marine ecosystems.
However, vast swathes of the South Pacific high seas remain open to bottom trawling – and New Zealand now stands as the last country still carrying out this destructive practice in the region. Bottom trawling doesn’t just scoop up what ends up in the net at the surface, the heavy nets plow the seafloor, breaking, crushing, and burying fragile species. Much of the destruction stays on the seabed, uncounted and invisible, but no less devastating. Understanding of the South Pacific’s deep-sea ecosystems is grounded in both scientific research and traditional knowledge passed down through generations. These knowledge systems tell us the same thing: the deep sea is not an empty wilderness but a rich and fragile environment that is deeply connected to broader ocean health. Yet these ecosystems face multiple threats including the physical destruction caused by bottom trawling, repeated coral bycatch, and the largely unknown, but likely compounding, impacts of climate change.
Protecting seamounts from bottom trawling is a critical first step in implementing the new High Seas Treaty, a legally binding agreement aimed at conserving biodiversity in areas beyond national jurisdiction. An estimated 58% of seamounts are found in the high seas and while the High Seas Treaty lays the foundation for creating marine protected areas (MPAs) in international waters, it has not yet entered into force and the legal tools to implement protections are still in development. That’s why regional fisheries management organizations (RFMOs) have a key role to play right now. They can act immediately to prevent further destruction by closing vulnerable areas to destructive bottom trawling and buying critical time until the Treaty’s protections can be fully realised.
The Lord Howe – South Tasman Sea site has been identified as a priority site for nomination as one of the first high seas MPAs under the High Seas Treaty. SPRFMO, as the regional body responsible for managing this area, already has the authority to designate Lord Howe – South Tasman Sea as an MPA. Recognising its ecological significance and moving to protect it now would be a significant step in safeguarding vulnerable deep-sea ecosystems in the South Pacific.