In 2020, the 250-person community of Tristan da Cunha announced the establishment of the fourth largest fullyprotected MPA in the world: the Tristan da Cunha Marine Protection Zone (MPZ). The MPZ protects 91 % of the 750,000 km2 EEZ in the South Atlantic, which is home to numerous endemic and endangered species reliant on the healthy marine environment. After legal gazettement in 2021, the next challenge is to build strong foundations for the MPZ that will support it in perpetuity. The Tristan da Cunha community and its partners are rising to this challenge by developing and implementing a programme of work focused on three core areas for MPZ success: effective management, research and monitoring, and community stewardship. Alongside assistance in MPZ management from the UK Government Blue Belt Programme and the establishment of a conservation endowment fund, the RSPB, Blue Nature Alliance, and Tristan da Cunha Government are providing dedicated support for the community for the first years of the MPZ. The partnership is supporting the establishment of monitoring programmes and citizen science initiatives, providing mentorship opportunities, facilitating global knowledge exchanges, strengthening the community's cultural connection to its marine environment and enhancing the global identity of the Tristan da Cunha community as 'Atlantic Guardians'. Providing support for the MPZ that is adaptive, flexible and community led, beyond the moment of designation is essential for the longevity of the Tristan da Cunha Marine Protection Zone.

The southern oceans are home to a large variety of organisms, including many endemic species. High levels of endemism are due in part to non-physical barriers limiting gene flow in marine species. The sooty albatross Phoebetria fusca is an endangered seabird breeding on seven island groups in Atlantic and Indian Oceans. We sequenced the mitochondrial control region (55 birds) and genotyped 10 microsatellite markers (88 birds) to examine the population genetics of sooty albatrosses from Tristan da Cunha and Gough Island (Atlantic Ocean), and Marion Island, Île de la Possession (Crozet) and Amsterdam Island (Indian Ocean), which together support > 99

Wilkins's Finch Nesospiza wilkinsi is endemic to Nightingale Island (2.5 km2), Tristan da Cunha. It feeds on the woody fruits of the Island Tree Phylica arborea and in 2017 had a population of 120 breeding pairs. In 2021 it was uplisted from " Endangered " to " Critically Endangered" following damage to P. arborea woodland during severe storms in 2019. During a brief visit to Nightingale in February 2024, we confirmed that the finch population in the area of storm-damaged woodland has decreased by up to 75%, but the density in other areas was similar to that prior to 2019. Extrapolating from the 2017 survey, we estimated the current population to be 60-90 breeding pairs. Surveys of P. arborea structure in the storm-affected area indicated that some large trees had survived, despite being flattened, that recruitment of new trees is occurring, and that fruit loads on surviving trees are similar to those in 2017. Satellite imagery from 2005 showed similar woodland loss during another severe storm in 2001 to that experienced in 2019, indicating that the finch has survived similar events in the past. Coupled with the successful release of a biological control agent to limit the impact of the introduced brown soft scale Coccus hesperidum on Phylica fruit production, the future prospect for Wilkins's Finch is less bleak than previously thought. However, the risk that global warming is increasing the frequency of severe storms remains a concern. Planting more woodland patches in sheltered areas would help to offset future storm damage.

Marine mammal sightings were recorded during research cruises to three remote, mid-ocean British Overseas Territories in the South Atlantic and Southern Ocean. In March to April 2018 and 2019, the Exclusive Economic Zones (EEZs) of tropical St Helena and temperate Tristan da Cunha were surveyed. The sub-polar waters of South Georgia and the South Sandwich Islands (SGSSI) were surveyed in February to March 2019. At St Helena in 2018, five species were recorded during 11 sightings, and in 2019, four species, with one additional unidentified species, during seven sightings. Most of these sightings were of dolphin species, which are known to be resident around the Island and seamounts. In Tristan da Cunha in 2018, a total of five identified and one unidentified species were recorded during six sightings, half of which were associated with the Islands or seamounts. In 2019, due to rough weather, no sightings were recorded in the Tristan da Cunha waters. Around SGSSI, 162 sightings of 236 cetaceans were made in 2019, mostly of baleen whales, with seven species identified with certainty. Sightings around the southern South Sandwich Islands included beaked whales and large dolphins, whereas baleen whales dominated in the northern South Sandwich Islands. These results provide new data for rarely surveyed regions, helping to build a spatial picture of important areas for marine mammals, which will help inform marine spatial protection strategies.

Beaches on Henderson Island, one of the Pitcairn Islands in the central South Pacific, have been reported to have some of the highest standing stocks of stranded plastic recorded. Surveys of floating debris at sea show that this is not related to high densities of plastic in the area. Only 19 macroplastic items were observed during 905 km of at-sea transects (0.5 items·km−2; 135 g·km−2). This low density confirms previous microplastic surveys which show that the Pitcairn group lies west of the South Pacific Gyre. Plastic loads on beaches at other islands in the Pitcairn group are not exceptional. The east coast of Henderson Island appears to be particularly effective at accumulating drifting debris, but many small plastic fragments on these beaches probably result from degradation in situ, so removing macroplastics will reduce the formation of microplastics.

The Tristan da Cunha archipelago comprises three main islands: Tristan, Inaccessible and Nightingale at 37ºS 12ºW, with Gough Island (40ºS 10ºW) the only other temperate oceanic island in the South Atlantic Ocean (Ryan 2007). Tristan and Gough are important breeding sites for 25 species of seabirds (Ryan 2008; Ryan et al. 2014; 2015; Robertson et al. 2016), and a further 30 species of non-breeding seabirds have been reported from the islands (Ryan 2007; Visser et al. 2009; Ryan 2010). We report three additional species from the islands based on observations from 2017 to 2019.

1. Halcrow Inc., 22 Cortlandt Street 31 Floor, New York, NY, 10007, USA, abayram@halcrow.com 2. Halcrow Inc., 4100 Boy Scout Blvd., Suite 580, Tampa, FL., 33607, USA, SchofieldAJ@halcrow.com 3. TranSystems, 6700 East Pacific Coast Highway, Suit 180, Long Beach, CA, 90803, USA, wdwood@transystems.com 4. Halcrow Inc. 6700 East Pacific Coast Highway, Suit 180, Long Beach, CA, 90803, USA, ZhenF@halcrow.com