High Seas Biodiversity Treaty: A Milestone for Ocean Protection

Image: Claire Greenwell

In June 2023, the United Nations adopted the High Seas Biodiversity Treaty, formally known as the Agreement on the Conservation and Sustainable Use of Marine Biological Diversity of Areas beyond National Jurisdiction (BBNJ). Developed under the United Nations Convention on the Law of the Sea, the treaty is the first global framework specifically designed to protect biodiversity in the high seas—areas of ocean beyond any single country’s control.

When did it come into effect?

The treaty officially entered into force on 17 January 2026, 120 days after the 60th country ratified it. Australia signed the agreement in September 2023 and has since passed national legislation to enable ratification.

Why does it matter?

Nearly 60% of the global ocean lies beyond national jurisdiction, making it one of the least protected ecosystems on Earth. These waters are increasingly impacted by fishing, shipping, and emerging industries, placing pressure on marine biodiversity and ocean health. Because ocean ecosystems are interconnected, the condition of the high seas directly affects coastal environments—including Australian waters.

What does the treaty do?

The High Seas Biodiversity Treaty establishes a framework to:

• Create marine protected areas in international waters

• Require environmental impact assessments for high seas activities

• Regulate access to marine genetic resources

• Support capacity building and marine technology sharing, particularly for developing states.

Implications for seabird conservation

For seabirds, many of which spend most of their lives at sea and only return to land to breed, this treaty is especially significant. It opens the door to protecting critical foraging habitats and migratory pathways that have historically lacked oversight. By improving management of high seas ecosystems, the treaty will help reduce threats such as overfishing and habitat degradation—key drivers of seabird population decline.

A global step forward

The treaty represents a major step toward the global goal of protecting 30% of the ocean by 2030. It also strengthens international collaboration in marine science and conservation—an essential foundation for safeguarding seabirds and the wider ocean ecosystem into the future.

To see which countries have signed or ratified the treaty, visit the United Nations Law of the Sea Treaty.

Image: Claire Greenwell

AOC 2027 - WA Student Travel Grants

For those seabird students in western Australia, a special grant is available for the next AOC in Auckland, NZ, held from 16 - 18 February 2027:

BirdLife Western Australia Postgraduate Student Sponsorship

The BirdLife Western Australia branch is pleased to be offering postgraduate student sponsorship to assist attendance at the AOC 2027. Two grants of $1,000 are being offered this year. These will be allocated on the basis of the merit, quality and relevance of submitted abstracts.

Closing date: 31 March 2026

Please submit your abstract via email (wa@birdlife.org.au)

Applications must include:

• A brief CV, including details of current course of study (institution, degree, thesis title and project overview)

• A copy of your submitted AOC 2027 abstract

• A letter of support from a course supervisor (can be emailed directly to BirdLife WA)

The conditions of this sponsorship are that applicants:

• Are enrolled for a postgraduate degree that is relevant to ornithology

• Are studying in Western Australia

• Have registered to attend the AOC 2027

• Are prepared to present a paper at this conference

• Have not received any other subsidy or grant to attend the AOC 2027.

Evidence for possible H5N1 reported from Heard Island

Eric J Woehler, ASG

Heard Island and the nearby McDonald Islands are located c.4100km southwest of Perth in the Southern Indian Ocean at 53°S 73°30’E. The islands are south of the Antarctic Polar Front and approximately 70% of the islands are permanently glaciated. The islands are a listed World Heritage property, and support globally significant populations of seabirds and marine mammals.

Media reports in late October 2025 suggested an Australian Antarctic Division expedition to Heard Island had identified unusual mortality in Southern Elephant Seals that were deemed to be consistent with H5N1 bird flu. The reports also noted there was no evidence of unusual mortality in any seabirds. With reports of H5N1 identified at the nearby French Iles Kerguelen 400km to the northwest of Heard Island, the suspected presence of H5N1 at Heard Island is warranted.

One unusual aspect of Southern Elephant Seal pups on Heard Island is that they can, and do, disperse widely from the foreshore harems once they are weaned. One of the challenges in censuses of elephant seals on Heard is that the weaners can be 100s of metres (and occasionally farther) from the foreshores. This behaviour is much more pronounced than on other Subantarctic islands where the coastal/foreshore real estate is much more constrained.

At western Heard Island, in an area known as the 'Four Bays', there is a large sandy plain (the "Nullarbor") that Southern Elephant Seal weaners use to move around and disperse. The plain is unvegetated, and the weaners that venture there are very conspicuous targets for predation events by Southern Giant Petrels and Subantarctic Skuas. It is not unusual to see weaners, alive and dead, subjected to predation/scavenging by giant petrels and skuas from mid-October (peak pup counts) onwards as weaners leave the harems and disperse.

Part of the Nullarbor, Heard Island. Image © Eric J Woehler

Vision aired on news media showed a scattered elephant seal pup carcasses on the Nullarbor being sampled, and the content was consistent with normal elephant seal weaner mortality at Heard Island. The samples collected will be returned to Australia for testing. Until the results are known, there remains no evidence for H5N1 at Heard Island. The absence of any reports of seabirds showing symptoms of H5N1 there are welcome. It may well be that the "unusual" mortality of elephant seals at Heard Island is normal post-weaning mortality of pups.

It is critical that the most stringent quarantine protocols are implemented for the return of the expeditioners, their equipment and samples etc. If H5N1 is present on Heard Island, the return to Australia of material/gear from the expedition may present an opportunity for H5N1 or variant/s to enter Australia.

Scientists visited the remote Heard Island as part of a seven-week research voyage on the icebreaker RSV Nuyina (Australian Antarctic Division: Rowena Hannaford). Photograph from ABC [https://www.abc.net.au/news/2025-10-25/bird-flu-h5n1-likely-present-in-heard-island-elephant-seals/105931840]