Balearic Shearwater watercolour by Helen Worthington, from a photograph by Pep Arcos

Jessica Phillips (Department of Zoology, Oxford University, UK) and colleagues have published open access in the journal Ecology and Evolution on at-sea observations of Critically Endangered Balearic Shearwaters Puffinus mauretanicus in UK waters.

The paper’s abstract follows:

“Aim.  Europe's only globally critically endangered seabird, the Balearic shearwater (Puffinus mauretanicus), is thought to have expanded its postbreeding range northwards into UK waters, though its at sea distribution there is not yet well understood. This study aims to identify environmental factors associated with the species’ presence, map the probability of presence of the species across the western English Channel and southern Celtic Sea, and estimate the number of individuals in this area.

Location.  The western English Channel and southern Celtic Sea.

Methods.  This study analyses strip transect data collected between 2013 and 2017 from vessel‐based surveys in the western English Channel and southern Celtic Sea during the Balearic shearwater's postbreeding period. Using environmental data collected directly and from remote sensors both Generalized Additive Models and the Random Forest machine learning model were used to determine shearwater presence at different locations. Abundance was estimated separately using a density multiplication approach.

Results.  Both models indicated that oceanographic features were better predictors of shearwater presence than fish abundance. Seafloor aspect, sea surface temperature, depth, salinity, and maximum current speed were the most important predictors. The estimated number of Balearic shearwaters in the prediction area ranged from 652 birds in 2017 to 6,904 birds in 2014.

Main conclusions.  Areas with consistently high probabilities of shearwater presence were identified at the Celtic Sea front. Our estimates suggest that the study area in southwest Britain supports between 2% and 23% of the global population of Balearic shearwaters. Based on the timing of the surveys (mainly in October), it is probable that most of the sighted shearwaters were immatures. This study provides the most complete understanding of Balearic shearwater distribution in UK waters available to date, information that will help inform any future conservation actions concerning this endangered species.”

Reference:

Phillips, J.A., Banks, A.N., Bolton, M., Brereton, T., Cazenave, P., Gillies, N., Padget, O., van der Kooij, J., Waggitt, J. & Guilford, T.  2021.  Consistent concentrations of critically endangered Balearic shearwaters in UK waters revealed by at‐sea surveys.  Ecology and Evolution doi.org/10.1002/ece3.7059.

John Cooper, ACAP Information Officer, 08 February 2021

 Black Petrel  in water colour gouache by Grisselle Chock, from the followimg photograph by Virginia Nicol

Black Petrel at sea, photograph by Virginia Nicol

Elizabeth ‘Biz’ Bell (Wildlife Management International Limited, Blenheim, New Zealand) published in 2016 in the journal Notornis on diving behaviour of the ACAP-listed and globally Endangered Black Petrel Procellaria parkinsoni.

The paper’s abstract follows:

“The black petrel (Procellaria parkinsoni) is recognised as the seabird species at greatest risk from commercial fishing activity within New Zealand fisheries waters. Despite the fact that valuable mitigation information could be obtained from such data, little is known about the diving ability of this species. Diving data were obtained from electronic time–depth recorders from 22 black petrels breeding on Great Barrier Island (Aotea), Hauraki Gulf, New Zealand, during the early chick rearing period from January-February in both 2013 and 2014. This paper presents the first information on the diving ability of black petrels. The deepest dive recorded was 34.3 m, but maximum dive depths varied considerably among individuals (range 0.8-34.3 m). The majority (86.8%) of all dives were < 5 m and black petrels rarely dived to depths of >10 m. The majority (92.7%) of dives were during the day and time of day had no major effect on dive depth. Only males dived at night, between 2300 and 0200 hours. This information could be used to improve mitigation measures for black petrel and other seabird bycatch in longline fisheries particularly in relation to recommended depths for unprotected hooks and line sink rates. To achieve the recommended minimum 10 m depth for unprotected hooks it has been shown that hooks have to be deployed at 6 knots with a 0.3 m/second line sink rate when using 100 m streamer lines. Adoption of these measures should further reduce black petrel bycatch in longline fisheries.

With thanks to Biz Bell, Grisselle Chock  and Virginia Nicol.  Note that ACAP Latest News missed featuring this paper when it was published.  It is posted now because of its importance for conserving the now nationally and globally Endangered species.

Reference:

Bell, E.A. 2016.  Diving behaviour of black petrels (Procellaria parkinsoni) in New Zealand waters and its relevance to fisheries interaction.  Notornis  63: 57-65.

John Cooper, ACAP Information Officer, 05 February 2021

The remains of a Black-browed Albatross recovered near a squid jigger in the south-west Atlantic

Tim Reid (Institute of Applied Ecology, University of Canberra, Australia.) and colleagues have published in the journal Aquatic Conservation: Marine and Freshwater Ecosystems on observations of Black-browed Albatrosses Thalassarche melanophris being deliberately caught by squid jigging vessels for human consumption.

The paper’s abstract follows:

“1. The waters of the Patagonian Shelf in the south-west Atlantic are nutrient rich, support large concentrations of wildlife, and are exploited by several fisheries, including the large Asian squid-jigging fishery. Although the squid-jigging fishery has previously been observed to have few problems with the accidental mortality of seabirds, the deliberate catch for consumption of seabirds by the crew has been identified as a possible issue.
2. Four cruises were made between Uruguay and the Falkland Islands during 2005–2006 to quantify the impact of jiggers on seabirds from indirect observation platforms. Monitoring included closely approaching 116 jigging vessels and boarding seven for inspection.
3. The use of non-jigging fishing gear, either for catching fish or seabirds, was observed at the stern of 33 vessels. Twelve seabird carcasses were observed floating close to vessels during 13 days of monitoring. Although the results recorded here are not sufficient to put a confident estimate on the magnitude of this mortality, the density of carcasses floating in the water among the jigging fleet indicated the potential significance of this problem.
4. The results were considered sufficiently concerning for the Falkland Islands Government to take preventative actions, including educational efforts, improving humanitarian conditions onboard vessels, introducing relevant legislation and licence conditions, and prosecuting intentional seabird take inside the Falkland Islands jurisdiction. This has resulted in the apparent elimination of these mortalities within Falkland waters since the late 2000s.
5. Nevertheless, it is likely that the same initial conditions exist for the crews of squid jiggers on vessels operating on the high seas, and so the possibility of the targeting of seabirds for consumption continues. Squid fisheries with substantial numbers of jiggers overlap with important foraging areas for a range of albatross and other species in high-seas areas such as the Patagonian Shelf, the Humboldt and Kuroshio currents, and the south-west Pacific Ocean. These areas of overlap may be important to investigate, especially in the foraging grounds of declining seabirds.”

A squid jigger in the south-west Atlantic

The corpse of a Black-browed Albatross floats at sea near a squid jigger in the south-west Atlantic

Photographs from Tim Reid

With thanks to Nigel Brothers and Tim Reid.

Reference:

Reid, T., Yates, O., Crofts, S. & Kuepfer, A. 2021  Interactions between seabirds and pelagic squid‐jigging vessels squid‐jigging.  Aquatic Conservation: Marine and Freshwater Ecosystems doi.org/10.1002/aqc.3503doi.org/10.1002/aqc.3503.

John Cooper, ACAP Information Officer, 04 February 2021

Black-browed Albatross at sea, photograph by Marcos de Campo

Jesica Andrea Paz (Instituto de Investigaciones Marinas y Costeras, Universidad Nacional de Mar del Plata, Argentina) and colleagues have published in the journal Emu - Austral Ornithology on the absence of sexual segregation in Black-browed Albatross Thalassarche melanophris at sea in the south-west Atlantic.

The paper’s abstract follows:

“Sexual segregation in habitat use occurs when sexes differ in their use of the physical environment and is widely reported among seabirds. The Black-browed Albatross (Thalassarche melanophris) is one of the most abundant seabird species in the south-west Atlantic, but whether the sexes differ in their habitat selection during winter remains unknown. Here, we tested for sexual segregation in adult and immature Black-browed Albatrosses during winter. Movement data from 21 satellite-tracked Black-browed Albatrosses across the south-west Atlantic Ocean between 2011 and 2015 were used to determine suitable foraging habitat for males (n = 7) and females (n = 14) using habitat selection models. Sexual segregation was then assessed using an index of niche overlap for immature and adult age classes. Variables with the highest importance in habitat selection models across all groups were depth and sea surface temperature. The highest probabilities of occurrence were in shallow waters and intermediate surface temperatures. No sexual segregation was found which may be because of the large abundance of prey in the region and moderate energy requirements during the non-breeding season. These results are relevant for spatially explicit conservation management in this region, including the designation of marine protected areas. Indeed, bycatch in fisheries is a major threat to seabirds in this area, and foraging behaviour and performance in winter of this keystone species will influence their future reproductive performance.”

Reference:

Paz, J.A., Seco Pon, J.P., Krüger, L., Favero, M. & Copello, S. 2021.  Is there sexual segregation in habitat selection by Black-browed Albatrosses wintering in the south-west Atlantic?  Emu – Austral Ornithology doi.org/10.1080/01584197.2020.1869910.

John Cooper, ACAP Information Officer, 03 February 2021