Agathe Gérard (Institut Méditerranéen de Biodiversité et d'Écologie marine et continentale (IMBE), Aix-Marseille Université, Centre IRD de Nouméa, Nouvelle-Calédonie, France) and colleagues have published in the journal Austral Ecology on testing the ability of Wedge-tailed Shearwaters Puffinus pacificus to react to the odour of Ship or Black Rats Rattus rattus.

The paper’s abstract follows:

“Seabirds are particularly vulnerable to introduced alien mammalian predators, especially invasive rats, which are the main contributors to seabird extinction and endangerment in many places worldwide.  However, this appears context-dependent because, paradoxically, cases of apparent long-term coexistence between rats and some species of seabird have been reported for centuries, in various locations.  Among seabirds, procellariiforms are known to have developed a range of olfactory-driven behaviours, such as partner recognition and homing.  Olfaction could be an effective means of recognizing and thereafter avoiding invasive predators.  However, the role of olfaction in predation risk assessment has not yet been examined in any procellariiform.  Here, we investigated, through a Y-maze experiment, whether the wedge-tailed shearwater (Puffinus pacificus) avoided the odour of one of the most damaging alien predators on islands, the ship rat (Rattus rattus).  The experiment was conducted in different ecological contexts on three neighbouring islets off New Caledonia having different communities of invasive rats.  Contrary to our expectations, the wedge-tailed shearwater either did not detect or did not avoid the odour of the ship rat, despite about 175 years of coexistence between rats and shearwaters in New Caledonia.  These findings highlight the need for further investigations (across species, across sites) into the factors underpinning the paradox between high vulnerability and the surprising long-term coexistence between procellariid seabirds and alien invasive rats.”

Wedge-tailed Shearwater, photograph by Alan Burger

Reference:

Gérard, A., Jourdan, H., Millon, A. & Vidal, E. 2015.  Anti-predator behaviour in a procellariid seabird: Wedge-tailed shearwaters.  Austral Ecology DOI: 10.1111/aec.12252.

John Cooper, ACAP Information Officer, 05 July 2015

José Seco (Department of Life Sciences, Marine and Environmental Sciences Centre (MARE), University of Coimbra, Portugal) and colleagues have published in the Journal of the Marine Biological Association of the United Kingdom on Short-finned Squid Illex argentinus taken by Grey-headed Thalassarche chrysostoma, Black-browed T. melanophris and Wandering Diomedea exulans Albatrosses.

The paper’s abstract follows:

“The diets of marine predators are a potential source of information about range shifts in their prey.  For example, the short-finned squid Illex argentinus, a commercially fished species on the Patagonian Shelf in the South Atlantic, has been reported in the diet of grey-headed, Thalassarche chrysostoma; black-browed, T. melanophris; and wandering, Diomedea exulans, albatrosses breeding at Bird Island, South Georgia (54°S 28°W) in the Southern Ocean.  Tracking data suggest that these birds may feed on I. argentinus while foraging in Southern Ocean waters during their breeding season.  This led to the hypothesis that I. argentinus may occur south of the Antarctic Polar Front.  To test this hypothesis, we used stable isotope analyses to assess the origin of I. argentinus.  We compared I. argentinus beaks from the diets of the three albatross species with beaks of cephalopod species endemic to the Patagonian Shelf and others from the Southern Ocean.  Our results show that I. argentinus from the diet of albatrosses at Bird Island have δ13C values in the range −18.77 to −15.28‰.  This is consistent with δ13C values for Octopus tehuelchus, a typical species from the Patagonian Shelf. In contrast, Alluroteuthis antarcticus, a Southern Ocean squid, has typically Antarctic δ13C in the range −25.46 to −18.61‰.  This suggests that I. argentinus originated from warmer waters of the Patagonian Shelf region.  It is more likely that the albatross species obtained I. argentinus by foraging in the Patagonian Shelf region than that I. argentinus naturally occurs south of the Antarctic Polar Front.”

Grey-headed Albatross, photograph by Mickey Reeves

Reference:

Seco, J., Daneria, G.A., Ceia, F,R. Vieira, R.P.,  Hill, S.J. & Xavier, J.C. 2015.  Distribution of short-finned squid Illex argentinus (Cephalopoda: Ommastrephidae) inferred from the diets of Southern Ocean albatrosses using stable isotope analyses.  Journal of the Marine Biological Association of the United Kingdom DOI: http://dx.doi.org/10.1017/S0025315415000752.

John Cooper, ACAP Information Officer, 04 July 2015

David Costantini (Department of Biology, University of Antwerp, Belgium) and Giacomo Dell'Omo have published in the on-line and open-access journal Conservation Physiology on assessing the health of Scopoli’s Shearwaters Calonectris diomedea by using biomarkers.

The paper’s abstract follows:

A major challenge in conservation physiology is to find out biomarkers that reliably reflect individual variation in wear and tear.  Recent work has suggested that biomarkers of oxidative stress may provide an additional tool to assess the health state of individuals and to predict fitness perspectives.  In this study, we assessed whether three biomarkers of plasma oxidative status predicted the following factors: (i) the resight probability as breeder in the next seasons; and (ii) the cumulative reproductive output over multiple years in Scopoli’s shearwaters (Calonectris diomedea) using a 7 year individual-based data set.  Our results show that shearwaters having higher levels of a marker of oxidative damage (reactive oxygen metabolites) in 2008 had a lower resight probability in the next years and a lower number of chicks raised from 2008 to 2014.  In contrast, two biomarkers of antioxidant defences (non-enzymatic antioxidant capacity of plasma and thiols) did not have any predictive value.  Increased concentrations of plasma reactive oxygen metabolites, together with the significant individual repeatability over time in this metric of oxidative stress found in numerous studies, suggest that this metric might serve as a blood-derived biomarker for health and fitness perspectives in birds and, possibly, also in other taxa.”

Scopoli's Shearwater, photograph by Pep Arcos

Reference:

Costantini, D. & Dell'Omo, G. 2015.  Oxidative stress predicts long-term resight probability and reproductive success in Scopoli's shearwater (Calonectris diomedea).  Conservation Physiology 3.  doi: 10.1093/conphys/cov024.  

John Cooper, ACAP Information Officer, 03 July 2015

Robin Thomson and colleagues (Oceans and Atmospheres Flagship, CSIRO Marine and Atmospheric Research, Hobart, Tasmania, Australia) write online in the open-access journal PLOS ONE on the effects of climate change and fisheries bycatch on Shy Albatrosses Thalassarche cauta.

The paper’s abstract follows:

“The impacts of climate change on marine species are often compounded by other stressors that make direct attribution and prediction difficult.  Shy albatrosses (Thalassarche cauta) breeding on Albatross Island, Tasmania, show an unusually restricted foraging range, allowing easier discrimination between the influence of non-climate stressors (fisheries bycatch) and environmental variation.  Local environmental conditions (rainfall, air temperature, and sea-surface height, an indicator of upwelling) during the vulnerable chick-rearing stage, have been correlated with breeding success of shy albatrosses.  We use an age-, stage- and sex-structured population model to explore potential relationships between local environmental factors and albatross breeding success while accounting for fisheries bycatch by trawl and longline fisheries.  The model uses time-series of observed breeding population counts, breeding success, adult and juvenile survival rates and a bycatch mortality observation for trawl fishing to estimate fisheries catchability, environmental influence, natural mortality rate, density dependence, and productivity.  Observed at-sea distributions for adult and juvenile birds were coupled with reported fishing effort to estimate vulnerability to incidental bycatch.  The inclusion of rainfall, temperature and sea-surface height as explanatory variables for annual chick mortality rate was statistically significant.  Global climate models predict little change in future local average rainfall, however, increases are forecast in both temperatures and upwelling, which are predicted to have detrimental and beneficial effects, respectively, on breeding success.  The model shows that mitigation of at least 50% of present bycatch is required to offset losses due to future temperature changes, even if upwelling increases substantially.  Our results highlight the benefits of using an integrated modeling approach, which uses available demographic as well as environmental data within a single estimation framework, to provide future predictions.  Such predictions inform the development of management options in the face of climate change.”

Shy Albatross, photograph by Drew Lee

Reference:

Thomson, R.B., Alderman, R.L., Tuck, G.N. & Hobday, A.J. 2015.  Effects of climate change and fisheries bycatch on Shy Albatross (Thalassarche cauta) in Southern Australia.  PLOS ONE  DOI: 10.1371/journal.pone.0127006.

John Cooper, ACAP Information Officer, 02 July 2015