Maria Cristina Fossi (Department of Physical Sciences, Earth and Environment, University of Siena, Italy) and colleagues have reviewed plastic ingestion and entangled in cetaceans and Near Threatened Flesh-footed Shearwaters Ardenna carneipes in the open-access Frontiers in Marine Science.

The paper’s abstract follows:

“Impacts of debris on marine fauna occur throughout the marine ecosystems, with adverse impacts documented on over 1,400 species; impacts can be divided into those arising from entanglement, and those from ingestion. Ingestion of, and entanglement in, debris has been documented in over 60% of all cetacean species. Seabirds are also impacted by debris predominately through entanglement and ingestion, with the number of species negatively impacted increasing from 138 to 174 over the past two decades. In the marine environment, cetaceans and seabirds are widely regarded as reliable sentinels due to their position near the top of the marine food web, conspicuous nature, and reliance on marine resources; for this reason, this paper is focused on seabirds and cetaceans as sentinels of ocean change. In particular, two case studies are considered in relation to different levels of environmental anthropogenic impact: the cetaceans of the Mediterranean Sea and seabirds of eastern Australia. Here we describe two recent studies used to diagnose the toxicological stress related to debris-associated pressures in cetaceans and seabirds. These studies highlight the diversity and scale of impacts being felt by marine species and the role these organisms can play in our society as charismatic sentinels of ocean health. Seabirds and marine mammals are exposed, in these key areas, to a variety of adversities that potentially decrease their survival or reproductive success. These include weather, food shortages, predators, competitors, parasites, disease, and human-induced effects and plastic pollution. Each factor affects seabirds and marine mammals in a different way, but more importantly, factors can also interact and create impacts far greater than any one factor alone. The Australian and Mediterranean case studies presented here emphasize the need to consider multiple sources of mortality when developing management plans for the conservation of vulnerable species.”

Plastic fragments get removed from the gut of a Flesh-footed Shearwater, photograph by Ian Hutton

Reference:

Fossi, M.C., Panti, C., Baini, M. & Lavers. J.K. 2018. ^. A review of plastic-associated pressures: cetaceans of the Mediterranean Sea and eastern Australian shearwaters as case studies.  Frontiers in Marine Science doi.org/10.3389/fmars.2018.00173/.

ACAP Information Officer, 04 June 2018

Richard Phillips (British Antarctic Survey, Cambridge, UK) and colleagues have published early (pre type-setting) view in the ornithological journal Ibis on mixed pairs in albatrosses.

The paper’s abstract follows:

“Given the rarity of hybridization in seabirds, which presumably relates to their very high philopatry, the degree of breeding‐site vagrancy should correspond with the incidence of mixed‐species pairing, although not necessarily of hybrids if there are behavioural or genetic barriers to successful reproduction. Using molecular methods, we verified that two of the three chicks hatched by a vagrant male White‐capped Albatross Thalassarche steadi paired with a female Black‐browed Albatross T. melanophris at South Georgia were genuine hybrids (these chicks died before fledging, but a third chick – the result of an extra‐pair copulation – fledged successfully). In a wider review, we could find only five known or suspected mixed‐species pairs, and three different hybrids in albatrosses, mostly between closely‐related species. This appears to reflect behavioural barriers to hybridization in sympatric species and the low incidence of breeding‐site vagrancy (which mainly involves single individuals that invariably associate with the most phenotypically‐similar local taxon). Breeding‐site vagrancy is most frequent in the ‘shy‐albatross’ complex, which could explain why genetic divergence occurred more recently in this group than in other Thalassarche, and hence exploratory behaviour appears to be more important than numerical abundance or breeding distribution in driving colonisation as well as hybridization processes in albatrosses.”

A vagrant Black-browed Albatross on a nest among Grey-headed Albatrosses on Marion Island, photograph by Genevieve Jones

Reference:

Phillips, R.A., Cooper, J. & Burg, T.M. 2018.  Breeding‐site vagrancy and hybridization in albatrosses.  Ibis doi.org/10.1111/ibi.12622.

John Cooper, ACAP Information Officer, 03 June 2018

Jaime Ramos (Marine and Environmental Sciences Centre, University of Coimbra, Portugal) and colleagues have published in the journal The Condor: Ornithological Applications on chick growth, trophic ecology, and foraging range in the Near threatened Cape Verde Shearwater Calonectris edwardsii .

The paper’s abstract follows:

“Varying environmental conditions have a strong effect on the reproductive- and feeding-ecology measures of seabirds. We assessed how annual variation in the isotopic niche of foraging adults during the chick-rearing season, the size of at-sea foraging areas, and oceanographic characteristics influenced annual variation in linear growth rate and asymptotic mass of Cape Verde Shearwater (Calonectris edwardsii) chicks in 2013–2015. We also examined correlations between chick growth measures and chlorophyll a concentration (CHL) and sea surface temperature anomaly (SSTa) within the foraging areas of their parents in 2014 and 2015. Oceanographic conditions were unfavorable in 2013, with lower CHL and higher SSTa. In 2013 chicks had a lower asymptotic mass, and foraging adults had a wider isotopic niche, larger at-sea home range, and larger foraging areas, suggesting that poor foraging conditions forced parents to search for prey over a larger area. We did not detect significant relationships between CHL and SSTa within the adults' foraging range or chick growth measures in 2014 and 2015. The relationship between oceanographic conditions and breeding success in Cape Verde Shearwater and other tropical seabirds should be examined further across years with varying environmental conditions, and with GPS tags that monitor the entire nesting period.”

Cape Verde Shearwaters, photographs by Jacob Gonzalez-Solis

 Reference:

Ramos, J.A., Rodrigues, I., Melo, T., Geraldes, P. & Paiva, V.H. 2018.  Variation in ocean conditions affects chick growth, trophic ecology, and foraging range in Cape Verde Shearwater.  The Condor 120: 283-290.

John Cooper, ACAP Information Officer, 30 May 2018

The ACAP-listed Grey-headed Albatross Thalassarche chrysostoma has been listed as globally Endangered because of a decline since the 1970s of its largest breeding population, occurring at South Georgia (Islas Georgias del Sur)*.  A recent resurvey of a subset of colonies at the island indicates a decrease in numbers over the last decade of 5% a year.

Recent analyses of long-term records of banded birds found that annual survival rates of juveniles were lower than expected and highly variable.

Records from observers on fishing vessels have shown that immature birds are killed by pelagic longline fisheries in areas that are not used regularly by non-breeding adults.  In addition, circumstantial evidence suggests that because of the population decline there may have been a density-dependent increase in predation by giant petrels Macronectes spp. of juvenile Grey-headed Albatrosses, both as they fledge and in the few days immediately thereafter when they often rest on the sea close to the island.

In May 2018, 16 satellite tags (PTTs) were attached to Grey-headed Albatross chicks prior to their departure from Bird Island to map foraging areas of juveniles in order to determine the overlap with fisheries and to obtain data on juvenile survival.  The birds are being tracked in near real-time using the Argos system.

Click here to follow the birds’ at sea movements and distances travelled, with updates expected several times a day.

Fledgling Grey-headed Albatross, photograph by Marienne de Villiers

With thanks to Richard Phillips.

Selected literature:

Clay, T.A., Manica, A., Ryan, P.G., Silk, J.R.D., Croxall, J.P., Ireland, L. & Phillips, R.A. 2016.  Proximate drivers of spatial segregation in non-breeding albatrosses.  Scientific Reports 6: 29932.

Pardo, D., Forcada, J., Wood, A.G., Tuck, G.N., Ireland, L., Pradel, R., Croxall, J.P. & Phillips, R.A. 2017.  Additive effects of climate and fisheries drive catastrophic declines in multiple albatross species.  Proceedings of the National Academy of Science of the Unites States of America 114: E10829-E10837.

Phillips, R.A., Gales, R., Baker, G.B., Double, M.C., Favero, M., Quintana, F., Tasker, M.L., Weimerskirch, H., Uhart, M. & Wolfaardt, A. 2016.  The conservation status and priorities for albatrosses and large petrels.   Biological Conservation 201: 169-183.

Poncet, S., Wolfaardt, A.C., Black, A., Browning, S., Lawton, K., Lee, J., Passfield, K., Strange, G. & Phillips, R.A. 2017.  Recent trends in numbers of wandering (Diomedea exulans), black-browed (Thalassarche melanophris) and grey-headed (T. chrysostoma) albatrosses breeding at South Georgia.  Polar Biology 40: 1347-1358.

John Cooper, ACAP Information Officer, 30 May 2018

*A dispute exists between the Governments of Argentina and the United Kingdom of Great Britain and Northern Ireland concerning sovereignty over the Falkland Islands (Islas Malvinas), South Georgia and the South Sandwich Islands (Islas Georgias del Sur y Islas Sandwich del Sur) and the surrounding maritime areas.