Leandro Tamini (Albatross Task Force Argentina, Programa Marino, Aves Argentina, Buenos Aires, Argentina) and colleagues have published in the journal Polar Biology on success achieved from using bird-scaring lines on bottom trawlers fishing on the Patagonian Shelf.

The paper’s abstract follows:

Seabird bycatch represents one of the main threats to vulnerable seabird populations, particularly albatross and petrels, and requires urgent conservation management interventions at a global scale.  We studied seabird mortality associated with demersal factory trawl vessels that target Argentine Hake Merluccius hubbsi along the Argentine Patagonian Shelf and tested the efficacy of bird-scaring lines as a seabird bycatch mitigation measure.  From November 2008 to June 2010, dedicated seabird observers recorded three sources of seabird mortality: entanglements with the trawl net; collisions with the trawl cables (corpses hauled aboard); and collisions with trawl cables (birds observed killed or injured).  During 141 days and 389 hauls, we recorded 17 seabird species associated with vessels, ten of which interacted with fishing gear.  The most vulnerable species was the black-browed albatross (Thalassarche melanophris).  From 41 recovered corpses, we identified black-browed albatross mortality rates of 0.013 and 0.093 birds/haul for net entanglement and cable collision (corpses hauled aboard), respectively.  From counts of birds killed or injured by cable collisions, we estimate a black-browed albatross mortality rate of 0.237 birds/h.   We use official fishing effort data to consider the potential scale of seabird mortality for the entire fleet and identify the main factors contributing to seabird mortality in this fishery. Bird-scaring lines eliminated seabird mortality caused by collisions with trawl cables and are recommended as a short- to medium-term measure to mitigate seabird mortality in this fishery.

Twin bird-scaring lines deployed behind a demersal hake trawler in the South Atlantic deterring Black-browed Albatrosses from collisions

Photograph by Barry Watkins

Reference:

Tamini, L.L., Chavez, L.N., Góngora, M.E., Yates, O., Rabuffetti, F.L. & Sullivan, B. 2015.  Estimating mortality of black-browed albatross (Thalassarche melanophris, Temminck, 1828) and other seabirds in the Argentinean factory trawl fleet and the use of bird-scaring lines as a mitigation measure.  Polar Biology DOI 10.1007/s00300-015-1747-3.

John Cooper, ACAP Information Officer, 19 July 2015

Minsmere is a nature reserve managed by the Royal Society for the Protection of Birds (RSPB) on the United Kingdom’s North Sea coast in the County of Suffolk.

On 12 July a Black-browed Albatross Thalassarche melanophris was photographed swimming in one of the reserve’s freshwater pools before flying out to sea shortly thereafter (click here).  For more photos of the albatross and a birder's description of the sighting click here.

The Minsmere Black-browed Albatross in flight

The albatross may well be the same bird as seen on the German island of Heligoland a few days earlier (click here) – which is also assumed to be the same bird as seen there last year (click here).

Southern-hemisphere albatrosses cross into the North Atlantic from time to time (click here).

Read more on the Mismere bird here.

John Cooper, ACAP Information Officer, 18 July 2015

Paul Sagar (National Institute of Water & Atmospheric Research Ltd, Christchurch, New Zealand) has tabled a final report at last month’s meeting of the Conservation Services Programme (CSP) of New Zealand’s Department of Conservation on the demography of Buller’s Albatrosses Thalassarche bulleri on The Snares.

The report's Executive Summary follows:

“This report presents a summary of the results of the collection of demographic data at three study colonies of Southern Buller’s Albatross Thalassarche bulleri bulleri breeding at The Snares from 23-29 March 2015.  Demographic studies at the three study colonies have been undertaken annually since 1992, and so this report incorporates some of these data in the current analysis.  Estimates of the numbers of breeding pairs, made by recording the contents of each nest mound, showed slight decreases in all three colonies over the numbers recorded during 2014.  With the assumption that the combined total number of breeding pairs in the three study colonies was representative of North East Island as a whole then the breeding population probably peaked in 2005-2006 and has since undergone marked annual variations.  A total of 295 birds that had been banded previously in the study colonies as breeding adults of unknown age were recaptured.  A further 26 breeding birds were banded in the study colonies - these are presumed to be first-time breeders.  During the period 1992-2004 all chicks that survived to near fledging in the study colonies were banded and their survival to return to the study colonies in subsequent years has been monitored.  This year 134 of these birds were recaptured, with birds from cohorts banded from 1999 to 2004 being recaptured for the first time, and so showing the long-term monitoring required to obtain reliable estimates of survival of such known-age birds.  A further 36 known-age birds, from cohorts banded 1996-2004, were found breeding for the first time, and so were recorded as being recruited to the breeding population.”

Buller's Albatross at The Snares, photograph by Paul Sagar

Click here to read earlier news items on Buller’s Albatrosses at The Snares.

Reference:

Sagar, P. 2015.  Population Study of Southern Buller's Albatrosses on The Snares.  Population Study of Buller's Albatrosses.  Prepared for Department of Conservation May 2015.  Christchurch: National Institute of Water & Atmospheric Research Ltd.  11 pp.

John Cooper, ACAP Information Officer, 17 July 2015

Geoffrey Tuck (CSIRO Oceans and Atmosphere Flagship, Hobart, Tasmania, Australia) and colleagues have published in the Journal of Applied Ecology on modelling Wandering Albatross Diomedea exulans population dynamics at the Crozet Islands.

The paper’s summary follows:

“1. Seabirds have been incidentally caught in distant-water longline fleets operating in the Southern Ocean since at least the 1970s, and breeding numbers for some populations have shown marked trends of decline and recovery concomitant with longline fishing effort within their distributions.  However, lacking is an understanding of how forms of among-individual heterogeneity may interact with fisheries bycatch and influence population dynamics.

2. We develop a model that uses comprehensive data on the spatial and temporal distributions of fishing effort and seabird foraging to estimate temporal overlaps, fishery catchability and consequent bycatch.  We apply a population model that is structured by age, sex, life stage and spatially to Crozet Island wandering albatross and explore how heterogeneity in susceptibility to capture may have influenced the population’s demography over time.

3. A model where some birds were assumed to be more susceptible to fisheries bycatch was able to successfully replicate the observed trend in breeding pairs.  Considerably poorer fits were found without this assumption.  Results suggested that the more susceptible birds may have been removed from the population by the 1990s.

4. The model was also able to highlight areas, times and fleets prone to increased bycatch.  Knowledge of these factors should assist fisheries and conservation management bodies to quantify and reduce seabird bycatch through spatial management and fleet-specific mitigation efforts.

5. Synthesis and application.  Many seabirds show complex life histories that make them highly susceptible to additional incidental mortality from fishing vessels.  By applying a population model that integrates key aspects of seabird and fishery dynamics, we were able to explain the observed trends in the breeding population of Crozet wandering albatross and identify key areas and fleets where further mitigation may be required.  In addition, the potential removal of a category of birds that shows increased susceptibility to capture has important implications for the conservation management of this population and other iconic species incidentally caught by large-scale commercial fisheries.”

Wandering Albatross chick, photograph by Kate Lawrence

Reference:

Tuck, G.N., Thomson, R.B., Barbraud, C., Delord, K., Louzao, M., Herrera, M. & Weimerskirch, H. 2015.  An integrated assessment model of seabird population dynamics: can individual heterogeneity in susceptibility to fishing explain abundance trends in Crozet wandering albatross?  Journal of Applied Ecology  doi: 10.1111/1365-2664.12462.

John Cooper, ACAP Information Officer, 16 July 2015