Cunha Archipelago Research Articles

Climate Mitigation through Biological Conservation: Extensive and Valuable Blue Carbon Natural Capital in Tristan da Cunha's Giant Marine Protected Zone.

Simple SummarySolving biodiversity loss and climate change are part of the same problem; intact natural habitats can provide powerful and efficient climate mitigation if protected. Beyond the land (forests), there is little appreciation of just how important ocean nature is to climate mitigation. Carbon captured, stored and the rate at which it is buried (sequestration) by marine organisms is called blue carbon. We measured how much blue carbon occurs around the remote islands and seamounts of the Tristan da Cunha archipelago Marine Protected Zone (MPZ). We estimated that there are 300 tonnes of carbon (tC) captured in seaweed biomass each year, a proportion of which will sink and become a part of the long-term sediment carbon store. In deeper water we found a standing stock of ~2.3 million tC in the shallowest 1000 m depths, of which equivalent to 0.8 million t of carbon dioxide has the potential to be sequestered. At current carbon prices, and were it to attract blue carbon credits, £24 million worth of blue carbon can potentially be sequestered from the standing stock of this small United Kingdom Overseas Territory. This standing stock is protected and growth could, therefore, generate an additional £3.5 million worth of sequestered carbon a year, making it an unrecognized major component of the local economy. The economic return on this example MPZ probably ranks highly amongst climate mitigation schemes. The message is that placing meaningful protection to carbon-rich natural habitats can massively help society fight climate change and biodiversity loss. Nations who provide this protection should be fairly compensated, particularly where it comes at the detriment of other economic uses of marine habitats.Carbon-rich habitats can provide powerful climate mitigation if meaningful protection is put in place. We attempted to quantify this around the Tristan da Cunha archipelago Marine Protected Area. Its shallows (<1000 m depth) are varied and productive. The 5.4 km2 of kelp stores ~60 tonnes of carbon (tC) and may export ~240 tC into surrounding depths. In deep-waters we analysed seabed data collected from three research cruises, including seabed mapping, camera imagery, seabed oceanography and benthic samples from mini-Agassiz trawl. Rich biological assemblages on seamounts significantly differed to the islands and carbon storage had complex drivers. We estimate ~2.3 million tC are stored in benthic biodiversity of waters <1000 m, which includes >0.22 million tC that can be sequestered (the proportion of the carbon captured that is expected to become buried in sediment or locked away in skeletal tissue for at least 100 years). Much of this carbon is captured by cold-water coral reefs as a mixture of inorganic (largely calcium carbonate) and organic compounds. As part of its 2020 Marine Protection Strategy, these deep-water reef systems are now protected by a full bottom-trawling ban throughout Tristan da Cunha and representative no take areas on its seamounts. This small United Kingdom Overseas Territory’s reef systems represent approximately 0.8 Mt CO2 equivalent sequestered carbon; valued at >£24 Million GBP (at the UN shadow price of carbon). Annual productivity of this protected standing stock generates an estimated £3 million worth of sequestered carbon a year, making it an unrecognized and potentially major component of the economy of small island nations like Tristan da Cunha. Conservation of near intact habitats are expected to provide strong climate and biodiversity returns, which are exemplified by this MPA.

Breeding biology of two sympatric Nesospiza finches at Nightingale Island, Tristan da Cunha

Nesospiza finches are a classic example of a simple adaptive radiation, with two ecologically distinct forms confined to the Tristan da Cunha Archipelago, South Atlantic Ocean: an abundant, small-billed dietary generalist, and a scarce, large-billed specialist. These have segregated into two species at Nightingale Island, but there is still local introgression between the two forms at Inaccessible Island. We describe the phenology and breeding behaviour of the two sympatric species at Nightingale Island (2.6 km2): Wilkins’s Finch Nesospiza wilkinsi (Endangered) and Nightingale Island Finch N. questi (Vulnerable). The finch breeding season starts in late October-November but the onset of breeding varies by 4–5 weeks among years. The small-billed Nightingale Island Finch typically (two of three study seasons) starts breeding 1–3 weeks earlier than the large-billed Wilkins’s Finch, unlike at Inaccessible Island where the Wilkins’s Finches start breeding first. Laying of initial clutches was quite well synchronised, peaking 1–2 weeks after the first nests were found. Females constructed the nests, which were mostly (&gt;90%) in dense Spartina arundinacea tussock grass stands and occasionally in ferns or sedge grasses. Clutches comprised one or two eggs, with no difference between Wilkins’s (1.66 ± 0.48) or Nightingale Island finch clutches (1.71 ± 0.46). Incubation periods averaged longer for Wilkins’s Finch (18.3 ± 0.5 d) than Nightingale Island Finch (17.7 ± 0.5 d), but this difference was not statistically significant. Females incubated the eggs, and were fed by the males. The difference in egg volume within two-egg clutches was 2–13% for Wilkins’s Finches (mean 5.9 ± 3.3%) and 1–19% for Nightingale Island Finches (mean 8.4 ± 5.3%). At least 31% of pairs re -laid after their first breeding attempt failed but there was no evidence of double brooding. Repeat nests were 0–20 m (mean 5.6 ± 4.9 m) from the initial nest site and inter-seasonal nest sites for 38 known pairs were 0–33 m apart (mean 12 ± 9 m). No inter-species pairs or hybrid birds were seen, but two instances of inter-species fledgling provisioning were observed.

Benthic Assemblage Composition of South Atlantic Seamounts

Seamounts and oceanic islands rise from the seafloor and provide suitable habitat for a diverse range of biological assemblages including Vulnerable Marine Ecosystems (VMEs). Whilst they have been the focus of some work globally, there has been little description of the biological and physical environments of seamounts in the South Atlantic Ocean. In this study, we characterized benthic assemblage composition from 13 seamounts and oceanic islands spanning 8–40°S within the exclusive economic zones (EEZs) of Ascension Island, Saint Helena and Tristan da Cunha. Drop camera imagery was collected between 170 and 1000 m. All fauna present in images were identified and quantified, and multivariate statistics were used to describe biological assemblages and identify their environmental drivers. Benthic communities of temperate regions (Tristan da Cunha archipelago) were shown to be distinct from those found in the tropics, with latitude and depth identified as key environmental drivers of assemblage composition. Our results are consistent with the current understanding of the biogeography of the South Atlantic, both in terms of the distinction between tropical and temperate regions, and the influence of depth and water mass structure on assemblage distribution. Faunal assemblages are similar to those observed in the North Atlantic in terms of functional groups. VMEs are present within the EEZs of all three territories and are potentially protected from some threats by large marine protected areas (MPAs). Our imagery, data and analyses provide a baseline for south Atlantic seamounts so that future monitoring can establish whether existing protected status is sufficient to conserve both unique biodiversity and considerable potential for vital ecosystem services.

Cryptic speciation and population differentiation in the yellow-nosed albatross species complex

The two species of yellow-nosed albatross, Atlantic (Thalassarche chlororhynchos) and Indian (T. carteri), are morphologically similar, but they differ in breeding behaviour and distribution. Both species are listed as endangered by the IUCN due to the limited number of breeding sites, threats from introduced predators and diseases, and impact of commercial fishing. We quantified genetic variation between and within the two species. Using nuclear (microsatellites and two nuclear sequences) and mitochondrial (control region) markers, we analysed 354 samples from four breeding islands (Atlantic: Nightingale, Inaccessible, and Gough; Indian: Amsterdam) and bycatch samples from South Africa and New Zealand. In addition to all markers separating the two species, nuclear markers showed Atlantic yellow-nosed albatrosses from Gough Island are genetically distinct from those breeding at Nightingale and Inaccessible Islands in the Tristan da Cunha archipelago. Nuclear markers confirmed that all bycatch samples were Indian yellow-nosed albatrosses, however, the bycatch birds from South Africa and New Zealand were distinct from each other and from birds breeding on Amsterdam Island, suggesting colony specific dispersal at sea. Our study supports the current recognition of two yellow-nosed albatross species and recognises genetically distinct groups of both Atlantic and Indian yellow-nosed albatross breeding on different islands, which is important for their conservation and management.

Population Size and Territories of Wilkins' Finches Nesospiza wilkinsi on Nightingale Island, Tristan da Cunha

Nesospiza finches are endemic to two small islands in the Tristan da Cunha Archipelago in the South Atlantic Ocean. The finches have radiated into two ecologically distinct forms at both islands: an abundant, small-billed dietary generalist, and a scarce, large-billed specialist. On Nightingale Island (area 2.6 km2), the endangered large-billed Wilkins' Finches N. wilkinsi use their strong bills to crack open the hard, nut-like fruits of Island Cape Myrtle Phylica arborea trees to access the seeds. Although Phylica fruits are available year-round, the finch population is constrained by the limited area of fruit bearing Phylica trees (c. 12 ha), which makes Wilkins' Finch one of the world's naturally rarest bird species. Prior to this study, rough estimates ranged from 30–85 pairs, but there has been no dedicated survey of the population size. Over the austral summers of 2012, 2016 and 2017 we systematically caught and colour ringed birds to better estimate the population size. Pairs were present wherever there are Phylica trees across the island, utilising even small, isolated Phylica copses. Mean territory size for 117 pairs in 2017 was 0.215 ± 0.094 ha (±SD, range 0.043–0.718) with a mean density of 9.8 pairs/ha in Phylica woodland. The total population was estimated to be 120 breeding pairs (c. 280–300 mature birds). The most pressing threat to the Wilkins' Finch population is the recent arrival of an invasive insect, the Brown Soft Scale Coccus hesperidum, and its associated sooty mould Seiridium phylicae, which reduces Phylica fruit loads and kills large trees. The potential use of a biological agent to control Brown Soft Scale infestations is being investigated, since without swift and effective mitigation, we predict the health of these woodlands will rapidly degrade with serious implications for the persistence of Wilkins' Finch. Until effective mitigation is taken, we recommend up-listing the species to Critically Endangered based on IUCN Red List Criterion B2.

The Sinking of Another Tristan da Cunha Moss Endemic and Its Phytogeographical Consequences

&lt;p&gt;The original material of &lt;em&gt;Isopterygium tristaniense &lt;/em&gt;Dixon, an endemic species of the Tristan da Cunha archipelago in the central South Atlantic Ocean, is taxonomically evaluated and some details of its morphology are illustrated. The species is found to be conspecific with the Holarctic &lt;em&gt;Pseudotaxiphyllum elegans &lt;/em&gt;(Brid.) Z.Iwats. and it is the third record of the species in the Southern Hemisphere. The global distribution of this species is reviewed and the distribution patterns of the South Atlantic mosses are briefly discussed.&lt;/p&gt;

Severe impact of introduced scale insects on Island Trees threatens endemic finches at the Tristan da Cunha archipelago

Inaccessible and Nightingale Islands are uninhabited islands in the Tristan da Cunha archipelago, central South Atlantic Ocean. Over the past decade, the spread and impacts of two species of invasive scale insects have increased steadily, severely affecting the Island Tree Phylica arborea woodlands and the endemic large-billed finches Nesospiza spp., which feed extensively on Phylica fruit. The first species, Greedy Scale Hemiberlesia rapax, causes local canopy diebacks and slightly reduced fruit loads. On Inaccessible, it appears to be only locally distributed, but on Nightingale it has spread rapidly since 2012 and now infects 95% of the Island Trees. The second species, Brown Soft Scale Coccus hesperidum and its associated sooty mould Seiridium phylicae, has expanded its range at Inaccessible since 2011, and colonised Nightingale by 2016. At Inaccessible, repeat transects between 2011 and 2018 show that Phylica fruit loads are markedly reduced and many large trees have died. Numbers of male Dunn's Finches N. acunhae dunnei, which rely on Phylica fruits, have declined by 50% in the last decade in heavily infested woodlands at Inaccessible Island, and some males in the most badly affected woodland are paired with small-billed Finches N. a. acunhae. If the trees on Nightingale follow a similar fate, the persistence of the endemic Wilkins' Finch N. wilkinsi will be under severe threat. The potential use of a biological agent to control C. hesperidium infestations should be investigated, since without swift and effective mitigation, we predict the health of these woodlands will degrade rapidly.

Important marine areas for the conservation of northern rockhopper penguins within the Tristan da Cunha Exclusive Economic Zone

The designation of Marine Protected Areas has become an important approach to conserving marine ecosystems that relies on robust information on the spatial distribution of biodiversity. We used GPS tracking data to identify marine Important Bird and Biodiversity Areas (IBAs) for the Endangered northern rockhopper penguin Eudyptes moseleyi within the Exclusive Economic Zone (EEZ) of Tristan da Cunha in the South Atlantic. Penguins were tracked throughout their breeding season from 3 of the 4 main islands in the Tristan da Cunha group. Foraging trips remained largely within the EEZ, with the exception of those from Gough Island during the incubation stage. We found substantial variability in trip duration and foraging range among breeding stages and islands, consistent use of areas among years and spatial segregation of the areas used by neighbouring islands. For colonies with no or insufficient tracking data, we defined marine IBAs based on the mean maximum foraging range and merged the areas identified to propose IBAs around the Tristan da Cunha archipelago and Gough Island. The 2 proposed marine IBAs encompass 2% of Tristan da Cunha’s EEZ, and are used by all northern rockhopper penguins breeding in the Tristan da Cunha group, representing ~90% of the global population. Currently, one of the main threats to northern rockhopper penguins within the Tristan da Cunha EEZ is marine pollution from shipping, and the risk of this would be reduced by declaring waters within 50 nautical miles of the coast as ‘areas to be avoided’.

Using playback to estimate the distribution and density of the world’s smallest flightless bird, the Inaccessible Island Rail Atlantisia rogersi

SummaryThe Inaccessible Island Rail Atlantisia rogersi, the world’s smallest extant flightless bird, is endemic to Inaccessible Island, a 14-km2 uninhabited island in the Tristan da Cunha archipelago, central South Atlantic Ocean. Rail populations are notoriously hard to survey and the rugged topography of Inaccessible Island makes a survey particularly challenging. Fortunately, Inaccessible Island Rails are very vocal, because their secretive behaviour means birds are hard to observe in the dense vegetation. We assessed the distribution of rails across Inaccessible Island using playbacks at 350 point-count sites in October–November 2018. Rail calls were heard at 98% of sites and we estimate the rail population to be in the order of 10,300 birds (95% CI 9,100–12,200), based on estimated rail densities in the six main habitats. Historic population estimates were reasonably crude and thus not suitable for inferring population trends, but the population appears to be stable and we recommend the species’ status remains as ‘Vulnerable’. The accidental introduction of alien mammals poses the greatest threat to the survival of the Inaccessible Island Rail and the removal of house mouse Mus musculus and ship rat Rattus rattus from neighbouring Tristan da Cunha Island would greatly reduce the risk of such a catastrophe.

Reassessment of Tristan da Cunha Gelidium (Gelidiales, Rhodophyta) species

Abstract Three endemic species of Gelidium have been described from the remote Tristan da Cunha archipelago. A recent barcode survey of Tristan da Cunha red algae in combination with the clarification of vouchers for previously sequenced specimens has prompted a molecular and morphological reassessment of these species. Analyses of rbcL and COI-5P data indicated that all sequenced Tristan da Cunha specimens represented a single taxon, and furthermore that this genetic group was conspecific with Gelidium micropterum from southern Africa. Morphologically the Tristan da Cunha specimens represented either Gelidium concinnum or Gelidium regulare, and there was a grade of character states between both of these species, as well as G. micropterum. Based on these results the synonymy of G. concinnum and G. regulare under G. micropterum is proposed and an expanded description of G. micropterum provided. None of the studied Tristan da Cunha specimens clearly fit the description of the third endemic species, Gelidium inflexum, and its status could not be determined.

Sub-Antarctic fur seals depredate northern rockhopper penguins at Nightingale Island, Tristan da Cunha

The most plausible hypothesis for declining population trends of some marine top predators at the northern extent of their breeding ranges in the Southern Ocean is that it results from environmental change. Sub-Antarctic fur seals Arctocephalus tropicalis are opportunistic and pelagic foragers that feed on a variety of fish, cephalopods, and crustaceans throughout their range. Penguins are also targeted, but to what extent remains uncertain, with only two records to date: Amsterdam Island, South Indian Ocean, where they kill and feed on northern rockhopper penguins Eudyptes moseleyi; and Gough Island, the southernmost island in the Tristan da Cunha archipelago, South Atlantic Ocean, where they are suspected to be significant predators of northern rockhopper penguins based on an unprecedented number of penguin carcasses (> 100) found floating at sea in 2011. We report the first documented records of such predations from the northern islands in the Tristan archipelago. Over three austral summers (2015–2017), northern rockhopper penguins with severe injuries were frequently observed at Nightingale Island. The cause of the wounds was unknown, but seal or shark attacks seemed probable. In January 2019, the first confirmed sighting of a sub-Antarctic fur seal, predating a healthy northern rockhopper penguin at sea off Nightingale Island was recorded. It remains uncertain whether the large A. tropicalis population at the Tristan da Cunha islands is significant predators of northern rockhopper penguins, but this could partly explain the significant recent decrease in northern rockhopper penguin population numbers.

Three new seabird species recorded at Tristan da Cunha archipelago

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.

Spatial ecology, phenological variability and moulting patterns of the Endangered Atlantic petrel Pterodroma incerta

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 40:189-206 (2019) - DOI: https://doi.org/10.3354/esr00991 ESR Special: Biologging in conservation Spatial ecology, phenological variability and moulting patterns of the Endangered Atlantic petrel Pterodroma incerta Marina Pastor-Prieto1,*, Raül Ramos1, Zuzana Zajková1,2, José Manuel Reyes-González1, Manuel L. Rivas1, Peter G. Ryan3, Jacob González-Solís1 1Institut de Recerca de la Biodiversitat (IRBio) and Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals (BEECA), Universitat de Barcelona, 08028 Barcelona, Spain 2Center for Advanced Studies of Blanes (CEAB-CSIC), 17300 Girona, Spain 3FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch 7701, South Africa *Corresponding author: marina.pastor6@gmail.com ABSTRACT: Insights into the year-round movements and behaviour of seabirds are essential to better understand their ecology and to evaluate possible threats at sea. The Atlantic petrel Pterodroma incerta is an Endangered gadfly petrel endemic to the South Atlantic Ocean, with virtually the entire population breeding on Gough Island (Tristan da Cunha archipelago). We describe adult phenology, habitat preferences and at-sea activity patterns for each phenological phase of the annual cycle and refine current knowledge about its distribution, by using light-level geolocators on 13 adults over 1-3 consecutive years. We also ascertained moulting pattern through stable isotope analysis (SIA) of nitrogen and carbon in feathers from 8 carcasses. On average, adults started their post-breeding migration on 25 December, taking 10 d to reach their non-breeding areas on the South American shelf slope. The pre-breeding migration started around 11 April and took 5 d. From phenological data, we found evidence of carry-over effects between successive breeding periods. The year-round distribution generally coincided with the potential distribution obtained from habitat modelling, except during the non-breeding and pre-laying exodus periods, when birds only used the western areas of the South Atlantic. Moulting occurred during the non-breeding period, when birds spent more time on the water, and results from SIA helped us to distinguish feathers grown around Gough Island from those grown in the non-breeding area. Overall, our results bring important new insights into the spatial ecology of this Endangered seabird, which should help improve conservation strategies in the South Atlantic Ocean. KEY WORDS: Atlantic petrel · Year-round movements · At-sea behaviour · Carry-over effects · Patagonian Shelf Full text in pdf format Supplementary material PreviousNextCite this article as: Pastor-Prieto M, Ramos R, Zajková Z, Reyes-González JM, Rivas ML, Ryan PG, González-Solís J (2019) Spatial ecology, phenological variability and moulting patterns of the Endangered Atlantic petrel Pterodroma incerta. Endang Species Res 40:189-206. https://doi.org/10.3354/esr00991 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 40. Online publication date: November 14, 2019 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2019 Inter-Research.

Stalked barnacles on an adult male sub-Antarctic fur seal at Inaccessible Island, Tristan da Cunha

An adult male sub-Antarctic fur seal, Arctocephalus tropicalis, on Inaccessible Island in the Tristan da Cunha archipelago (TdC), was observed infested with goose barnacles, likely Lepas australis. Although adult females have been recorded to carry goose barnacles, this is the first record from an adult male at a breeding island. Males remain at sea throughout winter, so it is not clear why there are not more records of goose barnacles attached to their pelage.

Early pupping of a sub-Antarctic fur seal at Inaccessible Island, Tristan da Cunha

A sub-Antarctic fur seal, Arctocephalus tropicalis, pup was located on Inaccessible Island in the Tristan da Cunha archipelago (TdC), well before the start of the annual breeding (pupping and mating) season in 2018. It was born a few days before 27 September 2018, at least 59 days before the next pup was observed on the island in 2018 and 75 days before the median birthdate for the species at the TdC. A malfunctioning of the obligate delay of implantation of the blastocyst in its mother was likely the cause of the early birth.

Diet of the spiny lobster Jasus paulensis from the Tristan da Cunha archipelago: Comparisons between islands, depths and lobster sizes

Diet of the Tristan spiny lobster Jasus paulensis was examined using gut content and Stable Isotope Analyses (SIA) to assess whether diets differed among three islands in the Tristan da Cunha archipelago (Inaccessible, Nightingale and Tristan islands), and between small and large lobsters at two depth intervals. Gut fullness was significantly less at Nightingale Island, suggesting overall less food there. Diet differed significantly among all islands, depths and sizes, although multidimensional scaling (MDS) and constrained canonical analysis of principle coordinates (CAP) plots showed considerable overlap and variability in diet. Lobster diet from Tristan Island showed a greater within-island similarity and was significantly less diverse, suggesting a more impoverished reef and narrower feeding niche, while dietary differences between size and depth reflected prey availability. Carbon and nitrogen stable isotope signatures differed among the islands, and carbon signatures between depths. Jasus paulensis appeared to be an opportunistic omnivore, with diet reflecting impoverished reef habitats. In addition, our data showed no evidence of soya remnants in the gut contents or tissue signatures of lobsters at Nightingale Island, following a soya spill there four years previously. However, gut fullness was less at Nightingale. This may have increased the attractiveness of baited traps, possibly explaining an observed rise in CPUE after the spill.

The origin of the world’s smallest flightless bird, the Inaccessible Island Rail Atlantisia rogersi (Aves: Rallidae)

Rails (Aves: Rallidae) are renowned for their extreme dispersal capability, which has given rise to numerous island lineages. Many insular species lost the ability to fly as a response to release from predator pressure—a feature causing rapid extinction when humans subsequently introduced mammals. The world’s smallest extant flightless bird, the Inaccessible Island Rail Atlantisia rogersi, is endemic to Inaccessible Island, Tristan da Cunha archipelago, in the central South Atlantic Ocean. It is placed in a monotypic genus, but its taxonomic affinity, as well as geographic origin, are disputed. Contrary to its suggested Old World origin, we demonstrate that the Inaccessible Island Rail is nested within the mainly South American ‘Laterallus clade’ and that it colonized ≥3 million-year-old Inaccessible Island from South America c. 1.5 million years ago. The taxonomy of rails has traditionally been based on morphology, and convergent evolution has caused many cases of misclassification. We suggest a re-classification within the ‘Laterallus clade’ and call for extended coverage of taxon sampling for DNA sequencing.

Effects of age, sex, colony and breeding phase on marine space use by Great Shearwaters Ardenna gravis in the South Atlantic

Shearwaters are among the most abundant seabirds globally and breeding birds often travel thousands of kilometres during foraging trips to productive marine areas. Great Shearwaters Ardenna gravis are endemic breeders of the Tristan da Cunha Archipelago with a population of 5–6 million breeding pairs making them key top predators within the South Atlantic Ocean. We deployed satellite transmitters on 42 breeding and non-breeding shearwaters at two nesting islands and one foraging site in the northern hemisphere to quantify their movements and space use with respect to age, sex, colonies and breeding phases. During the pre-laying period, birds from Gough Island made trips of 2400 km to the Benguela upwelling region off South Africa, or > 4000 km to the Patagonian Shelf; patterns which overlapped with immature birds from the Bay of Fundy, Canada. During the incubation period, males and females from Inaccessible Island showed differences in trip durations, but no difference in foraging ranges: both sexes made trips of 1500–2000 km to the Sub-Antarctic Front or 4000 km to the Patagonian Shelf, among the furthest foraging trips of breeding seabirds observed to date. Although the colonies are separated by only 400 km, during the incubation period, the at-sea distribution of non-breeding birds from Gough Island was spatially segregated from breeding and failed birds from Inaccessible Island, whereas immature birds from Fundy overlapped with birds from both colonies. During the post-breeding period, all tagged populations overlapped on the Patagonian Shelf. Argentina’s Exclusive Economic Zone was used extensively during pre-laying, incubation, and post-breeding periods, highlighting the global importance of the Patagonian Shelf for this species.

The distribution of breeding Sooty Albatrosses from the three most important breeding sites: Gough, Tristan and the Prince Edward Islands

ABSTRACTSooty Albatrosses (Phoebetria fusca; Endangered) breed only on sub-Antarctic islands in the South Atlantic and south-west Indian Oceans, with most of the population at Gough Island (≈37%), the Prince Edward Islands (≈24%) and the Tristan da Cunha archipelago (≈20%). Breeding Sooty Albatrosses from all three of these populations were tracked during the incubation and brood-guard periods. Birds from Marion Island (Prince Edwards) ranged farther north, despite being the most southerly of the three study sites. Tristan-Gough Sooty Albatrosses concentrated mostly around the Sub-Antarctic Front (SAF) in the southern Atlantic Ocean, whereas Marion birds were associated with both the SAF and the Sub-Tropical Front (STF) in the southern Indian Ocean. Our tracking data describe where 80% of breeding Sooty Albatrosses forage during the incubation and brood-guard period, including the first records of birds from Marion and Tristan. Such data are important to identify key areas where these threatened birds need protection from mortality on long-line fishing gear. Overlap with the distribution of tuna long-line effort was greater for Sooty Albatrosses from Tristan da Cunha and Gough Island than for Marion birds, suggesting that birds breeding at Atlantic colonies might be at greater risk of bycatch mortality in this fishery.

Using measurements to predict laying order in harvested Northern Rockhopper Penguin (Eudyptes moseleyi) eggs

The sustainable and responsible exploitation of natural populations for subsistence requires a scientific basis for management. Eggs of the Endangered Northern Rockhopper Penguin (Eudyptes moseleyi) in the Tristan da Cunha archipelago have been harvested since the 19th century with no restrictions on which (A- or B-eggs) can be harvested, despite the larger B-egg being much more likely to produce fledged offspring. Our objective was to create a discriminant function to predict the laying order of harvested eggs. We found that the discriminant function of D = 0.58 x Length + 0.39 x Breadth -57.48 successfully classified 91% of eggs as A- or B-eggs. When applied to previously collected harvest data, the discriminant function identified at least 36% of eggs as B-eggs. The method we describe here provides a mechanism around which one aspect of a management framework for the sustainable harvest of Northern Rockhopper Penguin eggs can be built.