Wandering Albatross by Grace Innemee 

Florian Orgeret (Marine Apex Predator Research Unit, Nelson Mandela University, Port Elizabeth, South Africa) and colleagues have published in the Journal of Animal Ecology on tracking globally Vulnerable Wandering Albatrosses at sea from Marion and Possession Islands’

The paper’s abstract follows:

“Sexual competition is increasingly recognized as an important selective pressure driving species distributions. However, few studies have investigated the relative importance of inter- vs. intrapopulation competition in relation to habitat availability and selection.

To explain spatial segregation between sexes that often occurs in non-territorial and central place foragers, such as seabirds, two hypotheses are commonly used. The ‘competitive exclusion’ hypothesis states that dominant individuals should exclude subordinate individuals through direct competition whereas the ‘niche divergence’ hypothesis states that segregation occurs due to past competition and habitat specialization.

We tested these hypotheses in two populations of an extreme wide-ranging and sexually dimorphic seabird, investigating the relative role of intrapopulation and interpopulation competition in influencing sex specific distribution and habitat preferences.

Using GPS loggers, we tracked 192 wandering albatrosses Diomedea exulans during four consecutive years (2016-2019), from two neighbouring populations in the Southern Ocean (Prince Edward and Crozet archipelagos). We simulated pseudo-tracks to create a null spatial distribution and used Kernel Density Estimates (KDE) and Resource Selection Functions (RSF) to distinguish the relative importance of within vs. between population competition.

KDE showed that only intrapopulation sexual segregation was significant for each monitoring year, and that tracks between the two colonies resulted in greater overlap than expected from the null distribution, especially for the females. RSF confirmed these results and highlighted key at-sea foraging areas, even if the estimated of at-sea densities were extremely low. These differences in selected areas between sites and sexes were, however, associated with high interannual variability in habitat preferences, with no clear specific preferences per site and sex.

Our results suggest that even with low at-sea population densities, historic intrapopulation competition in wide-ranging seabirds may have led to sexual dimorphism and niche specialization, favouring the ‘niche divergence’ hypothesis. In this study, we provide a protocol to study competition within as well as between populations of central place foragers. This is relevant for understanding their distribution patterns and population regulation, which could potentially improve management of threatened populations.”

Reference:

Orgeret, F., Reisinger, R.R., Carpenter-Kling, T., Keys, D.Z., Corbeau, A., Bost, C.-A., Weirmerskirch, H. & Pistorius, P.A. 2021.  Spatial segregation in a sexually-dimorphic central place forager: competitive exclusion or niche divergence?  Journal of Animal Ecology doi.org/10.1111/1365-2656.13552.

John Cooper, ACAP Information Officer, 22 June 2021

Still at risk from longlines: a breeding Wandering Albatross Diomedea exulans on Bird Island in the South Atlantic

Martin Collins (British Antarctic Survey, Cambridge, UK) and colleagues have published in the journal Marine Policy on the history of mitigating the impact on seabirds of a longline fishery for Patagonian Toothfish Dissostichus eleginoides in the South Atlantic.

The paper’s abstract follows:

“Seabird mortality in fisheries is a global problem and a major driver of the continued decline of many seabird populations. Unless appropriate mitigation is in place, longline fishing can cause high levels of seabird mortality. Here we describe the development and implementation of seabird mitigation measures in the Patagonian toothfish Dissostichus eleginoides fishery around the sub-Antarctic islands of South Georgia (CCAMLR Subarea 48.3), since the fishery began in the late 1980s. The initial high bycatch mortality (>5000 birds / 0.59 birds per 1000 hooks in 1996) has been reduced to negligible levels (<0.01 per 1000 hooks) through implementation of a suite of mitigation measures and a high level of compliance. The principal species killed in the fishery were black-browed albatross and white-chinned petrels, with most of the mortality occurring in April and early May. Whilst the synchronous introduction of much of the mitigation makes it is difficult to confirm which measures have been most effective, there is compelling evidence that the restriction of the fishery to the austral winter was a major factor. Night-setting and line-weighting measures have also been important in reducing mortality and the 100% observer coverage in the fishery has encouraged high levels of compliance. We also consider how different measures may be effective for different species and how novel measures, such as the use of marked hooks, have helped encourage compliance. The mitigation measures developed in the South Georgia fishery have subsequently been adopted in other CCAMLR fisheries and have helped guide global best practice in addressing seabird bycatch.”

With thanks to Richard Phillips, British Antarctic Survey.

Reference:

Collins, M.A., Hollyman, P.R., Clark J., Soeffker, M., Yates, O. & Phillips, R.A. 2021.  Mitigating the impact of longline fisheries on seabirds: lessons learned from the South Georgia Patagonian toothfish fishery (CCAMLR Subarea 48.3).  Marine Policy 131. doi.org/10.1016/j.marpol.2021.104618.

John Cooper, ACAP Information Officer, 21 June 2021

Post No. 7 for ‘WADWEEK2021’ 

Tristan Albatrosses display on Gough Island, photograph and buff design by Michelle Risi

Today’s World Albatross Day marks the twentieth anniversary of the signing of the Agreement on the Conservation of Albatrosses and Petrels (ACAP) in 2001.  The inaugural World Albatross Day was held on this day last year with the theme “Eradicating Island Pests”.  To mark the second World Albatross Day, this year’s selected theme is “Ensuring Albatross-friendly Fisheries”.

That thousands of albatrosses continue to die every year as a result of fishing operations is probably the major threat albatrosses face.  These magnificent birds get caught on hooks, become entangled in nets and collide with trawl cables, leading to death by drowning or injury.  Solutions are available to address this conservation crisis.  This year’s World Albatross Day aims to draw attention to the problem and to highlight best-practice solutions, such as the use of bird-scaring lines in both longline and trawl fisheries, line weighting and night setting or use of hook-shielding devices by longliners and management of offal discharge by trawlers.

The two Critically Endangered albatrosses, the Tristan Diomedea dabbenena of the UK’s Gough Island and the Waved Phoebastria irrorata from Ecuador’s Galapagos Islands, have been chosen to serve as ‘feature species’ to draw attention to the continuing threats all the world’s 22 species of albatrosses face at sea from fisheries.  ACAP has produced infographics of them that illustrate the at-sea threats they face.  An infographic has also been produced for the Vulnerable Wandering Albatross D. exulans that as well as from fisheries is threatened by introduced feral cats and rodents on some of its breeding islands.

In addition to the infographics in the three official ACAP languages of English, French and Spanish, ACAP has produced downloadable logos, posters and a music video to mark ‘WAD2021’.  Seven posts to ACAP Latest News, culminating in today’s, constitute ‘WADWEEK2021’ and go into more detail on World Albatross Day activities by ACAP and by other bodies around the world.  ACAP website posts about World Albatross Day have been shared to its Facebook Page.

Click here to access ACAP’s media statement for ‘WAD2021’ in the three official languages and in Portuguese.  Media statements marking World Albatross Day by BirdLife South Africa and the New Zealand Acting Minister of Conservation and from Brazil’s Centro Nacional de Pesquisa e Conservação de Aves Silvestres give more information on activities and priorities for action related to the conservation of albatrosses in their countries, as does Chile’s Subsecretaría de Pesca y Acuicultura (SUBPESCA).  Many more reports on ‘WAD2021” activities from ACAP Parties can be found on ACAP’s Facebook page and in ACAP Latest News.

John Cooper, ACAP Information Officer, 19 June 2021

Post No. 6 for ‘WADWEEK2021’

In the air and ready to fledge with its metal and colour bands: a translocated Black-footed Albatross on Isla Guadalupe - with a guano-splattered decoy watching on

The first globally Near Threatened Black-footed Albatross Phoebastria nigripes hatched and raised in Mexico fledged yesterday from Isla Guadalupe, just a few days before World Albatross Day on the 19th.  Named ‘Snowflake’, “it will wander around the Pacific Ocean for the next three to five years, after which it will come back to Guadalupe to search for a mate, and hopefully begin nesting on the island in 7-9 years, making it its new home.”

A translocated Black-footed Albatross chick with its Laysan Albatross foster parent on Isla Guadalupe

The fledgling was moved as an egg as part of a binational Black-footed Albatross translocation project from the USA’s Midway Atoll in Hawaii to Isla Guadalupe in Mexico, where it was hatched and raised by Laysan Albatross P. immutabilis foster parents (whose own egg was deemed infertile).  Two NGOs, Hawaii’s Pacific Rim Conservation (PRC) and Mexico’s Grupo de Ecología y Conservación de Islas (GECI), coordinated efforts with the federal governments of both countries to transfer 21 eggs (of which 18 hatched) and nine chicks (which have been hand raised) between the two islands.

“In the following days, one by one, the remaining 26 fully feathered chicks will begin their first flight to adulthood.  We wish them all the best, hoping to see them again in a few years. Guadalupe Island and all of us will be waiting for you with open arms.”  For the next couple of years, the binational team aims to move up to 42 eggs and 25 chicks per year in order to have at least 100 individuals to form a new breeding colony on Guadalupe.

The ACAP Secretariat comments on the significance of the translocation project

The significance comes from its international nature.  Whereas chicks of three species of albatrosses have been successfully translocated by air over long distances previously within Japan and the USA, this is the first time a translocation has involved two countries.  If successful, resulting in the establishment of a new colony, an Isla Guadalupe population of Black-footed Albatrosses will represent a substantial increase in the species’ population distribution, add a second albatross to the list of Mexican breeding species and be one safe from projected sea-level rise.

Further, establishment of a Black-footed Albatross breeding colony on Isla Guadalupe is seen as giving increased value to Mexico becoming a Party to the Agreement on the Conservation of Albatrosses and Petrels (ACAP) and contributing to albatross conservation efforts at a global level.  At present, Mexico attends ACAP meetings as an observer.

News and photographs by J.A. Soriano from Pacific Rim Conservation and GECI Facebook pages.

John Cooper, ACAP Information Officer, 18 June 2021