“The guiding heart”, a Buller’s Albatross Thalassarche bulleri by Virginia Nicol, Artists & Biologists Unite for Nature (ABUN) for World Albatross Day 2024

Aimee van der Reis and colleagues (Faculty of Science, The University of Auckland, New Zealand ) have produced a final report for the Department of Conservation’s Conservation Service Programme that looks at the diets of 10 species of albatrosses that breed within or visit New Zealand in relation to fishery discards.

The report’s executive summary follows:

“Seabird injury or mortality caused by interactions with New Zealand commercial fishing activities is a major conservation concern with the majority of interactions occurring in the surface longline (SLL) and trawl (TWL) fisheries.  Albatrosses (Diomedeidae) are among the most threatened and the majority of these long-lived, large seabirds have broad geographic ranges.vvv Seabirds are attracted to fishing vessel activity as an additional food source and this puts them at risk of interacting with vessel structures and fishing gear. This includes incidental capture whilst feeding on bait and discards. It is not clear to what extent the diet of albatrosses consists of naturally foraged prey in comparison to fisheries bait/waste associated with fishing activity, and ultimately their reliance on commercial fisheries as a food source.

In this dietary study, scat from colony birds and stomach contents from necropsy samples (commercial fishing mortalities) were used to detect taxa consumed by 10 albatross species using DNA metabarcoding.   Scat samples (n=86) were opportunistically collected from four subantarctic islands between January 2019 to April 2024.  Albatross necropsies (n=72) took place from September 2022 to February 2024.  Based on the frequency of occurrence, the diet among all albatross samples consisted largely of fishes (> 50% deep-sea and beyond known albatross diving depths) and to lesser extent cephalopods.   Differences in prey diversity (higher in necropsy samples) were found to be significant between sample type, however, no specific prey species were found to be responsible for this difference.  Observer and fisher reported bait and discard species were predominantly squid and mackerel.

Overall, the majority of fish and cephalopod species identified in both colony scat and necropsy samples overlapped extensively with species that were most likely to be made available through SLL and TWL fisheries activities, i.e., discard/species targeted/bait used. These results suggest that albatrosses are heavily reliant on fisheries as a food source whether they were sampled from fishing vessels (i.e., necropsy) or from nesting sites (i.e., scats).”

Reference:

van der Reis, A., Fei Tham, F, & Jeffs, A. 2025. Albatross Diet: Composition of Natural Prey versus Fisheries Bait/Waste.   Auckland: The University of Auckland.  [42 pp.]

John Cooper, Emeritus Information Officer, Agreement on the Conservation of Albatrosses and Petrels, 1x February 2025

Giant petrels scavenge from a seal carcass on Bird Island, photograph by Richard Phillips

William Mills (British Antarctic Survey, UK) and colleagues have published open access in the journal Environmental Research on annual trends in mercury contamination of giant petrels Macronectes spp. in the South Atlantic. “This study demonstrates decreasing Hg contamination of giant petrels during the 2010s at [Bird Island], which corresponded with changes in their trophic niches (i.e., a likely reduction in carrion consumption) and was related to annual indices of fur seal carrion availability (dead pups).

The paper’s abstract follows:

“Annual variation in prey availability can influence seabird diets and hence their exposure to pollutants, including mercury (Hg).  Among seabirds, those species that scavenge carrion of marine mammals and other top predators may be especially vulnerable to accumulating high Hg concentrations.  In this study, total Hg (THg) concentrations and carbon (δ¹³C) and nitrogen (δ¹⁵N) stable isotope values were measured in chick feathers of northern giant petrels Macronectes halli and southern giant petrels M. giganteus at Bird Island, South Georgia (2013–2020).  Both species are opportunistic predator-scavengers which feed mainly on penguins and Antarctic fur seal Arctocephalus gazella carrion, and to lesser extents on marine prey and other seabirds.  THg concentrations were not significantly different between northern giant petrels and southern giant petrels (means ± SDs, 2.49 ± 0.92 μg g⁻¹ dw and 2.34 ± 0.85 μg g⁻¹ dw, respectively), but concentrations in both species declined significantly over time, as did δ¹³C and δ¹⁵N values.  Annual feather THg concentrations of giant petrels were positively correlated with the number of dead Antarctic fur seal pups and their mortality rate at Bird Island, but not with population sizes or breeding success of penguins.  Accordingly, these results suggest a shift away from carrion (associated with the decreasing size and productivity of the Antarctic fur seal population) and towards the consumption of prey from lower trophic levels (e.g., Antarctic krill Euphausia superba), with a corresponding reduction in dietary Hg exposure.  Future work should investigate the consequences of changing prey availability for diets and pollutant exposure to other marine predators within the South Georgia and Scotia Sea marine ecosystems, given the ongoing environmental changes in the region.”

With thanks to Richard Phillips.

Reference:

Mills, W.F., Buss, D.L., Bustamante, P., Ramírez, F., Forcada, J., Forero, B.G. & Phillips, R.A. 2025.  Annual trends in mercury contamination are associated with changing trophic niches of giant petrels,  Environmental Research 270,  121010.

John Cooper, Emeritus Information Officer, Agreement on the Conservation of Albatrosses and Petrels, 18 February 2025

Motuhara/Forty-Fours from the air, photograph by Barry Baker

Peter Frost (Science Support Service, Whanganui, New Zealand) has reported to the Department of Conservation’s Conservation Service Programme on the December 2023 aerial survey of Northern Royal Albatrosses Diomedea sanfordi on the Chatham Islands.  The report's executive summary follows.

"A total of 4322 occupied nests of Northern Royal Albatross | Toroa, Diomedea sanfordi, was counted on aerial photographs taken on 9 December 2023 during an aerial survey of three offshore islands in the Chatham Islands group: Motuhara (1853 occupied nests); Rangitautahi (1501); and Te Awanui (968).  The birds were at the early incubation stage of their breeding cycle.  These islands support almost the entire global breeding population of the species.

The number of birds assumed to be occupying nests on Motuhara (1853), derived from the analysis of the aerial photographs, was 300 more than those counted on the ground 6 weeks later on 20 January 2024 (a total of 1472 active or recently failed nests). Some birds could have been sitting on eggs at the time of the aerial survey but failed before the ground count was made 6 weeks later and were not identified then as such. The possibility of a small, systematic, positive bias in counting birds as occupying a nest when they were not, must also be considered.

The estimate of 4322 occupied toroa nests overall is slightly above the average reported for the corresponding stage during the 2017–2023 breeding seasons (4021 ± 117 nests), but still around 1224 fewer than that reported for 2007– 2010 (5546 ± 159 nests). The slight apparent increase may be due to the higher breeding success reported in recent years (53.7 ± 8.9%) relative to that recorded in 2007–2010 (39.3 ± 6.3%). This may be associated with increases in vegetation cover, at least on Motuhara and Te Awanui.

Recommendations include:

1. Regular monitoring of the Northern Royal Albatross population breeding on the Chatham Islands should continue, ideally involving twice yearly aerial surveys, once during the early incubation period, then again immediately prior to the chicks fledging, to enable calculation of breeding success.
2. Close liaison between those conducting periodic ground-based studies on Motuhara and those planning the aerial surveys is needed to ensure, as close as possible, synchrony between the two, so that the population assessments are comparable, and any sources of potential bias identified.
3. Under present circumstances, where it is nearly impossible for the aerial survey data alone to produce absolutely accurate counts of the number of breeding pairs of Northern Royal Albatrosses (i.e., excluding birds sitting on empty nests), it may be more practical to continue reporting the number of occupied nests (which may include a proportion of birds sitting on empty nests) to maintain comparability with earlier aerial surveys, also essentially just of birds occupying nests. Nevertheless, work on trying to identify and reduce sources of bias, inherent in assessing aerial photographs, should continue.
4. The permanent sample plots set up on Motuhara to monitor population trends of both Northern Royal Albatross and Northern Buller’s Mollymawk populations on Motuhara should continue to be maintained and surveyed, along with finding ways to reduce errors in interpretation."

A Northern Royal Albatross family by Virginia Nicol‎ of, Artists & Biologists Unite for Nature (ABUN), after a photograph by Junichi Sugishita

Reference:

Frost, P.G.H. 2024. Aerial Survey of Northern Royal Albatross |Toroa (Diomedea sanfordi) Populations on the Chatham Islands, December 2023.  Whanganui: Science Support Service.  32 pp.

John Cooper, Emeritus Information Officer, Agreement on the Conservation of Albatrosses and Petrels, 17 February 2025

Dunedin Leisure Lodge

The Eighth Session of ACAP's Meeting of the Parties (MoP8) will be held in the Dunedin Leisure Lodge, Dunedin, New Zealand over 19-23 May 2025.  The meeting’s Second Circular gives information and key dates for applications for observer status, registration and submission of documents and information papers.

A Heads of Delegation Meeting will take place in the Lodge’s Meeting Room on Sunday 18 May 2025 at 18h00 NZST.

14 February 2025