Caroline Pott and David Wiedenfeld (American Bird Conservancy, The Plains, Virginia, USA) have reviewed information gaps in seabird bycatch in the journal Biological Conservation.

The paper’s abstract follows:

“Seabirds, as foragers in marine waters for at least part of their lifecycle, encounter the global fishing fleet in search of marine resources. While fishing gear is designed to catch fish and invertebrates, it also catches unintended species, including seabirds. We reviewed bycatch incidence for 378 marine and coastal bird species in 18 different gear types, and found that 60% (228 species) have been recorded interacting with at least one type of fishing gear. At least one species from each of the taxonomic groups analyzed (generally at the family level) has been documented interacting with fishing gear. With respect to two measures of degree of interaction, four families have a high degree of documented interaction: Gaviidae (loons or divers), Podicipedidae (grebes), Diomedeidae (albatrosses) and Sulidae (boobies and gannets). Set and drift gillnets (among the most studied gear types), have the greatest number of documented species interactions: 92 and 88 species, respectively. Hook gear (longlines and handlines) have documented interactions with 127 species. Together these four gear types have documented bycatch of 193 species. The waters of the Arctic, the Caribbean, the Guinea and Canary Currents in the Atlantic, the Indian Ocean and Asia have been poorly studied. Particular gear types, including industrially-deployed seines, and the artisanal fisheries sector also constitute significant gaps in our knowledge of seabird bycatch patterns worldwide.”

A bird-scaring line keeps seabirds at bay from the trawler warp, photograph by Leo Tamini 

With thanks to Caroline Pott: “Your news items were of great use to me when I was knee-deep in seabird lit research.”

Reference:

Pott, C. & Wiedenfeld, D.A. 2017.  Information gaps limit our understanding of seabird bycatch in global fisheries. Biological Conservation 210: 192-204.

John Cooper, ACAP Information Officer, 24 May 2018

Natalia Montesdeoca (Department of Animal Pathology, Veterinary Faculty, University of Las Palmas de Gran Canaria, Arucas, Las Palmas, Spain) and colleagues have published in the on-line journal PLoS ONE on seabirds, including Cory’s Shearwaters Calonectris borealis treated by a rehabilitation centre in the Canary Islands.

The paper’s abstract follows:

Aims

The aims of this study were to analyze the causes of morbidity and mortality in a large population of seabirds admitted to the Tafira Wildlife Rehabilitation Center (TWRC) in Gran Canaria Island, Spain, from 2003 to 2013, and to analyze the outcomes of the rehabilitation process.

Methods

We included 1,956 seabirds (133 dead on admission and 1,823 admitted alive) in this study. Causes of morbidity were classified into nine categories: light pollution (fallout), fishing gear interaction, crude oil, poisoning/intoxication, other traumas, metabolic/nutritional disorder, orphaned young birds, other causes, and unknown/undetermined. The crude and stratified (by causes of admission) rates of the three final disposition categories (euthanasia Er, unassisted mortality Mr, and release Rr), the time until death, and the length of stay were also studied for the seabirds admitted alive.

Results

Yellow-legged Gull (Larus michahellis) was the species most frequently admitted (46.52%), followed by Cory’s Shearwater (Calonectris diomedea borealis) (20.09%). The most frequent causes of morbidity were light pollution (fallout) (25.81%), poisoning/intoxication (24.69%), and other traumas (18.14%). The final disposition rates were: Er = 15.35%, Mr = 16.29%, and Rr = 68.34%. The highest Er was observed in the ‘other traumas’ category (58.08%). Seabirds admitted due to metabolic/nutritional disorder had the highest Mr (50%). The highest Rr was observed in the light pollution (fallout) category (99.20%).

Conclusions

This survey provides useful information for the conservation of several seabird species. We suggest that at least the stratified analysis by causes of admission of the three final disposition rates, and the parameters time until death and length of stay at the center should be included in the outcome research of the rehabilitation of seabirds. The high release rate for seabirds (68.34%) achieved at the TWRC emphasizes the importance of wildlife rehabilitation centers for the conservation of seabirds.

A fledgling Cory's Shearwater downed by city lights 

Reference:

Montesdeoca, N., Calabuig, P., Corbera, J.A. & Orós, J. 2017.  A long-term retrospective study on rehabilitation of seabirds in Gran Canaria Island, Spain (2003-2013).  PLoS ONE doi.org/10.1371/journal.pone.0177366.

John Cooper, ACAP Information Officer, 23 May 2017

The project “Sustainable Management of Tuna Fisheries and Biodiversity Conservation in the Areas Beyond National Jurisdiction (ABNJ)”, (also known as the “Common Oceans Tuna Project”) aims to achieve responsibility, efficiency and sustainability in tuna production and biodiversity conservation within the ABNJ.

The Food and Agriculture Organization of the United Nations (FAO) is the overall implementing agency of the project, and BirdLife International, through one of its national partners, BirdLife South Africa, is implementing the seabird bycatch component. The seabird bycatch component of the project has a number of separate, but aligned, areas of work. These include increasing awareness and capacity of observer programmes regarding seabird bycatch mitigation, and building capacity of national scientists from key countries in the area of bycatch data collection and analysis, and facilitating a collaborative approach to the assessment of seabird bycatch.

The first stage of the seabird bycatch assessment process involved two regional pre-assessment workshops, one held in Skukuza, Kruger National Park, South Africa in February 2017, and the second in Hoi An, Vietnam in April 2017. The workshops brought national scientists and other experts together to discuss the challenges associated with assessing and monitoring seabird bycatch, including the availability of data and methodological approaches for such analyses. Importantly, the workshops also facilitated constructive discussions towards a collaborative assessment of seabird bycatch and the effectiveness of relevant Conservation and Management Measures in southern hemisphere tuna fisheries operating within ABNJ.

Attendees at the ABNJ workshop held in Vietnam

ACAP's Anton Wolfaardt makes his presentation to an ABNJ workshop, photographs by Bronwyn Maree

Two further workshops are planned as part of the process, the first to prepare and collate the required data for a collaborative assessment, and the final workshop to conduct the assessment. These are likely to take place in 2018 and early 2019, respectively.

ACAP was represented at both pre-assessment workshops by the Convenor of its Seabird Bycatch Working Group, Anton Wolfaardt.

An article on the two workshops can be found on the Common Oceans project website.  Click here for earlier accounts on the ABNJ’s activities in ACAP Latest News.

Anton Wolfaardt, Convenor, ACAP Seabird Bycatch Working Group, 22 May 2017

Letizia Campioni (MARE - Marine and Environmental Sciences Centre, Instituto Universitário, Lisbon, Portugal) and colleagues have published in the journal Animal Behaviour on visits to non-natal colonies by pre-breeding Black-browed Albatrosses Thalassarche melanophris.

The paper’s abstract follows:

“In long-lived species with delayed maturity, prebreeders are expected to gather information by visiting and sampling the quality of potential nesting areas (prospecting), before they choose where to breed. In most seabirds, this process is important because, once recruited, individuals generally remain site-faithful throughout their long reproductive life. As many seabirds are believed to display low levels of natal dispersal, it is possible that natal philopatry is an obligate strategy for most individuals, with prospecting being a negligible activity during the prebreeding stage. Using ringing information and GPS technology, we tracked breeding adults and prebreeder black-browed albatrosses, Thalassarche melanophris, from a colony of the Falkland Islands, during the breeding season. Breeding adults rarely engaged in prospecting, whereas prebreeders showed a high propensity to visit other colonies. Most prebreeders started prospecting ashore when 4–5 years old and most of the younger individuals prospected more than one breeding colony, with some prospecting up to five colonies in just 9 days. Prospecting activity did not differ between males and females and rapidly declined as prebreeders aged, by which time individuals had probably already selected their future nesting site. Nestling body mass at 60 days of age and hatching date did not influence prospecting behaviour later in life. Prospecting was mostly directed at colonies within 10 km from the natal place, but occurred regularly up to 55–65 km. While distance from the natal place was a strong predictor of the probability of a colony being prospected, colony size and growth rate were not. Our results provide new insights into the role of prospecting in the process of recruitment, showing that even for highly philopatric birds, recruitment to the natal colony (or to another nesting site) has the potential to be informed, not done blindly.”

With thanks to Letizia Campioni for information and photograph.

Reference:

Campioni, L., Granadeiro, J.P. & Catry, P. 2017.  Albatrosses prospect before choosing a home: intrinsic and extrinsic sources of variability in visit rates.  Animal Behaviour 128: 85-93.

John Cooper, ACAP Information Officer, 19 May 2017