José Marcus Godoy (Instituto de Radioproteção e Dosimetria, Rio de Janeiro, Brazil) and colleagues have published in the Journal of Environmental Radioactivity on ²¹⁰polonium and ²¹⁰lead in South Atlantic seabirds, including the ACAP-listed Black-browed Albatross Thalassarche melanophris and White-chinned Petrel Procellaria aequinoctialis.

The paper’s abstract follows:

“In this study, we report the ²¹⁰Po and ²¹⁰Pb concentrations of bone, muscle and liver samples that were obtained from twelve different marine bird species stranded on beaches in the central–north region of Rio de Janeiro State.  Both radionuclides were highly concentrated in the liver samples; however, the lowest mean ²¹⁰Po/²¹⁰Pb activity ratio (1.3) was observed in bones compared with liver and muscle (16.8 and 13.8, respectively).  Among the species that were studied, Fregata magnificens, with a diet based exclusively on fish, had the lowest ²¹⁰Pb and ²¹⁰Po concentrations and the lowest ²¹⁰Po/²¹⁰Pb activity ratio.  The ²¹⁰Po concentrations in Puffinus spp. liver samples followed a log-normal distribution, with a geometric mean of 300 Bq kg^-1_{wet weight}.  Only two references pertaining to ²¹⁰Po in marine birds were found in a Web of Science search of the literature, and each study reported a different concentration value.  The values determined in this experiment are consistent with those in one of the previous studies, which also included one of the species studied in this work.  No values for ²¹⁰Pb in marine birds have been published previously.”

Black-browed Albatross, photograph by John Larsen

Reference:

Godoy, J.M.,  Siciliano, S., de Carvalho, Z.L., Tavares, D.C., de Moura, J.F. & Godoy, M.L.D.P.  2014.  ²¹⁰Polonium and ²¹⁰lead content of marine birds from southeastern Brazil. Journal of Environmental Radioactivity 135: 108-112.

John Cooper, ACAP Information Officer, 15 July 2014

Jarrod Santora (Center for Stock Assessment Research, University of California at Santa Cruz, California, USA) writes in the journal Polar Biology on top predators, including ACAP-listed giant petrels Macronectes spp., within winter pack ice off the Antarctic Peninsula.

The paper’s abstract follows:

“Global warming is predicted to reduce the amount of sea ice concentration in polar environments, thus presenting profound changes for populations of seabirds and marine mammals dependent on sea ice.  Using data from a shipboard survey during August 2012, I test the hypothesis that relative abundance of seabird and marine mammals reflects environmental variability associated with the dynamic pack ice zone.  Using environmental data and observations of sea ice concentration, I quantified an environmental gradient that describes the spatial organization of the dynamic pack ice zone.  The relationship of top predators to this environmental gradient revealed three important aspects: (1) an open water and pack ice community is present with some top predator species exhibiting higher abundance associated with moderate sea ice concentration (40–60 %) as opposed to the pack ice edge (10 %), (2) Antarctic fur seals (Arctocephalus gazella) were the most abundant pinniped and they were observed resting on ice floes and foraging within leads and polynyas, and (3) for the most abundant species, spatial regression models indicate that latitude and sea ice concentration (a principal north/south gradient) are the most important environmental determinants.  Winter ocean conditions may strongly influence population dynamics of top predators; therefore, information regarding their habitat use during winter is needed for understanding ecosystem dynamics."

A Southern Giant Petrel in Antarctica, photograph by Michael Dunn

Click here to read of a related paper by the same author.

Reference:

Santora, J.A. 2014.  Environmental determinants of top predator distribution within the dynamic winter pack ice zone of the northern Antarctic Peninsula.  Polar Biology DOI .

John Cooper, ACAP Information Officer, 14 July 2014

Fernanda Colabuono (Universidade de São Paulo, Instituto Oceanográfico, Laboratório de Química Orgânica Marinha, São Paulo, Brazil) and colleagues have published in the Marine Pollution Bulletin on carbon and nitrogen stable isotopes and organochlorine contaminants in five species of South Atlantic albatrosses and petrels.

The paper’s abstract follows:

“Carbon and nitrogen stable isotopes in albatrosses and petrels collected off southern Brazil were compared with concentrations of organochlorine contaminants (OCs).  δ¹³C and δ¹⁵N values, as well as OCs concentrations, exhibited a high degree of variability among individuals and overlap among species.  δ¹³C values reflected latitudinal differences among species, with lower values found in Wandering and Tristan Albatrosses and higher values found in Black-browed and Atlantic Yellow-nosed Albatrosses and White-chinned Petrels.  Some relationships were found between OCs and stable isotopes, but in general a partial ‘uncoupling’ was observed between OCs concentrations and stable isotopes ratios (especially forδ¹⁵N).  δ¹³C andδ¹⁵N values in Procellariiformes tissues during the non-breeding season appear to be a better indicator of foraging habitats than of trophic relationships, which may partially explain the high degree of variability between concentrations of OCs and stable isotopes ratios in birds with a diversified diet and wide foraging range.”

Tristan Albatross off South America, photograph by Martin Abreu

Reference:

Colabuono, F.I, Barquete, V., Taniguchi, S., Ryan, P.G. & Montone, R.C. 2014.  Stable isotopes of carbon and nitrogen in the study of organochlorine contaminants in albatrosses and petrels.  Marine Pollution Bulletin 83: 241-247.

John Cooper, ACAP Information Officer, 13 July 2014

Following the success of the Million Dollar Mouse Campaign in raising funds to support the costs of ridding New Zealand’s Antipodes Island of its introduced House Mice Mus musculus (click here) a Department of Conservation (DOC) expedition is leaving for the island around month end and ahead of next year’s planned bait drop (click here).

Looking across from Antipodes Island to mouse-free Bollons Island

Photograph by Erica Sommer

The Antipodes supports seven species of ACAP-listed albatrosses and petrels, including the Vulnerable Antipodean Albatross Diomedea antipodensis. (click here)  Chicks of two closely related species, the Critically Endangered Tristan Albatross D. dabbenena of Gough Island and the Vulnerable Wandering Albatross D. exulans of Marion Island are attacked by House Mice leading to deaths as reported previously in ACAP Latest News, and although not yet reported such attacks could occur on the Antipodes.

A pair of Antipodean Albatrosses, photograph by Erica Sommer

Antipodes Islands mouse eradication project manager Stephen Horn reports that “with a million dollars raised towards the project, and a series of trials already completed, it was time to start what would be a long battle.” (click here)

As part of the expedition, scientists will assess the populations of non-target biota, including the Antipodes Cyanoramphus unicolor and Reischek's C. hochstetteri Parakeets, Antipodes Island Snipe Coenocorypha aucklandica meinertzhagenae and the Antipodes Island Pipit Anthus novaeseelandiae steindachneri - all endemic taxa - on nearby and mouse-free Bollons Island.  Pipits are to be captured to conduct husbandry trials so that a population can be taken into temporary captivity during the bait drop.

Click here and here to read of last year’s expedition to the island, conducted to undertake studies of the island’s biota threatened by mice.

Together with the other four sub-Antarctic island groups belonging to New Zealand the Antipodes form part of a World Heritage Site, in addition to being a National Nature Reserve and are both Important and Endemic Bird Areas.

John Cooper, ACAP Information Officer, 12 July 2014