Maite Louzao (Instituto Español de Oceanografía, Xixón, Spain) and colleagues have published open-access in the journal Movement Ecology on foraging strategy of the Wandering Albatross Diomedea exulans.

The paper’s abstract follows:

“How foragers move across the landscape to search for resources and obtain energy is a central issue in ecology. Direct energetic quantification of animal movements allows for testing optimal foraging theory predictions which assumes that animals forage so as to maximise net energy gain.  Thanks to biologging advances, we coupled instantaneous energy-budget models and behavioural mode analysis to test optimal foraging theory predictions on wandering albatross Diomedea exulans during the brooding period.   Specifically, the instantaneous energy-budget model considered the energetic balance (i.e., the difference between empirical energy gain data and modelled energy expenditure via heart rate values) along the trajectory of a given individual.  Four stereotypic instantaneous behavioural modes were identified based on trajectory properties (e.g., speed and turning angle) by applying a new algorithm called Expectation Maximization Binary Clustering.  Previous studies on this species have shown that foraging-in-flight is the optimal foraging strategy during the incubation period when albatrosses undertake long-distance movements but no specific foraging strategy has been determined for shorter foraging movements (e.g., brooding period).”

A Wanderer at sea, photograph by John Chardine

With thanks to Maite Louzao for information.

Reference:

Maite Louzao, M., Wiegand, T., Bartumeus, F. & Weimerskirch, H. 2014.  Coupling instantaneous energy-budget models and behavioural mode analysis to estimate optimal foraging strategy: an example with wandering albatrosses.  Movement Ecology doi:10.1186/2051-3933-2-8.

John Cooper, ACAP Information Officer, 30 May 2014

Sylvia Zakkak (Department of Ecology, Aristotle University of Thessaloniki, Greece) and colleagues write in the open-access journal Marine Ornithologyon at-sea densities and extrapolated numbers of Scopoli’s Calonectris diomedea and Yelkouan Puffinus yelkouan Shearwaters (both potential candidates for ACAP listing) in the Aegean Sea.

The paper’s abstract follows:

“We estimate the population size of the three most abundant seabird species in the north Aegean Sea (Calonectris diomedea, Larus michahellis and Puffinus yelkouan), along with their distribution patterns. Sampling was carried out from May to September 2009 in line transects 300 m or 600 m wide and with a total length of 3 007 km. The sampling was opportunistic, using a variety of ships. After the data were corrected for movement bias, populations were estimated by using two types of stratification method:  novel fractal–based method as well as generalized additive models, which yielded the most conservative estimate of the population, although all estimates were quite similar. Overall, taking the mean estimate of the three most credible methods, we estimate the density of birds for the area to be 0.46 birds/km² for the three species together (C. diomedea 0.10 birds/km², L. michahellis 0.11 birds/km² and P. yelkouan 0.26 birds/km²). These densities of seabirds in the north Aegean are smaller than observed in studies in other parts of the world, but not surprisingly so, given the low productivity of the north Aegean. In view of the widespread and growing threats to seabird populations, the results of this study provide a useful basis for further scientific studies and for applied research including the designation of marine Important Bird Areas for the region.”

Yelkouan Shearwaters at sea

Reference:

Zakkak, S., Panagiotopoulou, M., & Halley, J.M. 2013.  Estimating the abundance of seabirds in the north Aegean Sea.  Marine Ornithology 41: 141-148.

John Cooper, ACAP Information Officer, 23 March 2014

Sayaka Uematsu (School of Marine and Tropical Biology, James Cook University, Cairns Queensland  Australia) and colleagues look at physiological responses of Streaked Shearwater Calonectris leucomelas chicks to potential radionuclide exposure following the Fukushima nuclear accident in the journal Ecological Indicators.

The paper’s abstract follows:

“The Fukushima nuclear accident in 2011 released significant amounts of radionuclides into the marine environment.  Exposure to radiation reduces levels of antioxidants such as carotenoids and vitamins A and E within exposed individuals.  Such reductions can cause teratogenic or mutagenetic effects leading to reduced reproductive viability and fitness.  Reduced antioxidant levels therefore may be used as an indicator of radionuclide contamination and to infer individual or population level impacts; however, the taxa-specific responses of marine organisms, such as seabirds, are poorly understood.  As top predators, seabirds are ideal bio-indicators of the prevalence of contaminants and pollutants in marine ecosystems.  At-sea foraging distributions of Streaked Shearwaters (Calonectris leucomelas) from Mikura Island (MKR), Japan during the post egg-laying period coincide with the Fukushima nuclear plume while the breeding colony on Birou Island (BRU) lies outside the affected zone.  We examined the physiological responses of Streaked Shearwater chicks at MKR and BRU to possible radiation exposure during the 2011 breeding season, four to seven months after the Fukushima nuclear accident.  Fledging mass did not differ between islands but fledglings from MKR displayed significantly reduced vitamin A levels.  Available information suggests these depletions most likely result from radiation exposure due to the Fukushima nuclear accident, implying that the risk of radionuclide contamination is considerably elevated for Streaked Shearwaters on MKR, where more than 60% of the world's population breeds.  While additional negative impacts are expected due to delayed effects of radionuclide transport via biomagnification in the food chain, this study highlights the potential immediate and worrisome consequences of the Fukushima nuclear accident for marine wildlife.”

Reference:

Uematsu, S., Uematsu, K. J. Lavers, J.L. & Congdon, B.C. 2014.  Reduced vitamin A (retinol) levels indicate radionuclide exposure in Streaked Shearwaters (Calonectris leucomelas) following the 2011 Fukushima nuclear accident.  Ecological Indicators 43: 244-251.

John Cooper, ACAP Information Officer, 29 May 2014

Jean-Baptiste Thiebot (Centre d’Études Biologiques de Chizé, Villiers-en-Bois, France) and colleagues have published in the journal Endangered Species Research on the results of at-sea tracking of Amsterdam Albatrosses Diomedea amsterdamensis.

The paper’s abstract follows:

“Long-lived animals typically exhibit several stages throughout their life-cycle during which their distribution may vary substantially, which may challenge the relevance of protection measures to them.  Here we surveyed individual movements of the critically endangered Amsterdam albatross from Amsterdam Island, southern Indian Ocean, during all its life-cycle stages.  Our goal was to identify, from the areas visited by the albatrosses, which coastal states share responsibility in regulating industrial fishing in their own Economic Exclusive Zone (EEZ) in order to promote the preservation of this species.   Using modern, stage-relevant tracking techniques (satellite tags, GPS and GLS loggers), we surveyed 361 at-sea trips in 93 individuals over 9 years, covering incubation, brooding, chick-rearing, sabbatical, failed-breeding, juvenile and immature stages. Our data show that Amsterdam albatrosses exhibit a wide and variable foraging radius (from 326 ± 193 km during brooding to 5519 ± 766 km for immatures) and at-sea distribution across stages, putting them beyond the French EEZ of Amsterdam Island for all or part of the trips surveyed in each stage.  The albatrosses visited the EEZs of France, South Africa, Australia, Madagascar, Mauritius and Namibia.   Wider-scale distribution of the non-breeders took them to more countries' Economic Exclusive Zones: 3–4 (France, South Africa, Australia and Namibia) versus 1–3 (France, Madagascar, Mauritius) for individuals in non-breeding and breeding stages, respectively. This study stresses the relevance of obtaining synoptic information on threatened species' distribution to address conservation questions, especially regarding the breeding versus non-breeding categories of the populations."

An Amsterdam Albatross off South Africa, photograph by Trevor Hardaker

Reference:

Thiebot, J.-B., Delord, K., Marteau, C. & Weimerskirch, H. 2014.  Stage-dependent distribution of the critically endangered Amsterdam albatross in relation to Economic Exclusive Zones.  Endangered Species Research 23: 263-276.

John Cooper, ACAP Information Officer, 28 April 2014