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

ACAP’s Executive Secretary attended the inaugural meeting of the Western and Central Pacific Fisheries Commission's (WCPFC) Electronic Reporting and Electronic Monitoring Intersessional Working Group (ERandEMWG1), held from 8-10 July in Nadi, Fiji (click here for the meeting's report and documents).

The main focus of the meeting was to draft electronic reporting (ER) standard data fields for operational observer data.  The draft standards use agreed international standards, where appropriate, to facilitate data sharing across RFMOs.  Use of E-Reporting is expected to increase dramatically the timeliness and accuracy of fisheries data submitted to the WCPFC.

Representatives at the meeting reported on a wide range of work being conducted in the region on both ER and electronic monitoring (EM) systems.  The question of the use of electronic data in legal proceedings was discussed and it was noted that this issue has already been successfully addressed domestically by some Members.  Following consideration of the draft data field standards it was agreed seek further comment on the appropriateness of these standards by relevant experts and to trial the standards with the use of sample data.  The draft standards were forwarded for consideration by the WCPFC’s Technical Compliance Committee (TCC11) whose next meeting will be held in Pohnpei, Federated States of Micronesia in September this year, prior to consideration by the next meeting (12th, Bali, Indonesia, December 2015) of the WCPFC Commission.

WCPFC E-Reporting (ER) and E-Monitoring (EM) Intersessional Working Group meets in Fiji

In relation to electronic monitoring, the Working Group recognised that EM systems can support and complement observer programmes and its development was encouraged in areas where data gaps exist, such as longline observer coverage and high-seas transhipments.  It was noted that use of this technology could be of particular use in small longline vessels that did not have the capacity to accommodate an observer, as well as on larger vessels whose trips may extend for over a year, which makes placement of an observer on these vessels very challenging.

Click here for more news of the ERandEMWG1 meeting.

Warren Papworth, ACAP Executive Secretary, 15 July 2015

Rachel Buxton (Department of Fish, Wildlife and Conservation Biology, Colorado State University, Fort Collins, USA) will host a discussion on behalf on the World Seabird Union on Twitter (#seabirdersaturday) this coming Saturday, 18 July, from 1530-1730 GMT on acoustic monitoring in seabirds (including burrowing species – of which seven petrels and shearwaters are ACAP-listed) as described below.

“Seabirds are among the most threatened group of marine animals.  Accordingly, over the past few decades, seabird conservation efforts have increased; including the eradication of harmful introduced predators from breeding sites and implementation of fisheries by-catch mitigation.  Population monitoring has therefore become especially important, to inform adaptive management by measuring the outcome of conservation efforts and to provide estimates for trajectory models under predicted future conditions.  Despite their threat status and the importance of long-term monitoring, seabird population estimates remain scarce because of the financial and logistical challenges associated with accessing remote island breeding sites.  Moreover, many seabirds have cryptic nesting behavior, including below-ground nesting and nocturnal colony attendance, precluding the use of conventional monitoring techniques.

More recently, passive acoustic recorders and automated acoustic analysis have received wide attention as powerful tools to monitor vocalizing wildlife.  Colonial seabirds lend themselves to acoustic monitoring, as their aggregated distribution reduces the spatial coverage required for monitoring and the number of vocalizations have [sic] been linked to relative abundance.  Moreover, the burgeoning field of acoustic ecology examines the relationship between the soundscape (combination of sounds from an environment) and ecosystem functioning.  In this way, acoustic monitoring provides an opportunity to not only monitor seabird populations, but also the broader island landscape” (click here).

White-chinned Petrels, photograph by Dave Boyle

Selected Literature:

Borker, A.L., McKown, M.W., Ackerman, J.T, Eagles-Smith, C.A., Tershy, B.R. & Croll, D.A. 2014.  Vocal activity as a low cost and scalable index of seabird colony size.  Conservation Biology 28: 1100-1108.

Buxton, R.T. & Jones, I.L. 2012.  Measuring nocturnal seabird activity and status using acoustic recording devices: applications for island restoration.  Journal of Field Ornithology 83: 47-60.

Buxton, R.T., Major, H.L., Jones ,IL. & Williams, J.C. 2013.  Examining patterns in nocturnal seabird activity and recovery across the western Aleutian Islands, Alaska, using automated acoustic recording.  The Auk 130: 331-341.

Blumstein, D.T., et al. 2011.  Acoustic monitoring in terrestrial environments using microphone arrays: applications, technological considerations and prospectus.  Journal of Applied Ecology 48: 758-767.

Oppel, S., Hervias, S., Oliveira, N., Pipa, T., Silva, C., Geraldes, P., Goh, M., Immler, E. & McKown, M.W. 2014.  Estimating population size of a nocturnal burrow-nesting seabird using acoustic monitoring and habitat mapping.  Nature Conservation 7: 1-13.

Pijanowski, .B.C., Villanueva-Rivera, L.J., Dumyahn, S.L., Farina, A., Krause, B.L., Napoletano, B.M., Gage, S.H. & Pieretti, N. 2011.  Soundscape ecology: the science of sound in the landscape.  Bioscience 61: 203-216.

John Cooper, ACAP Information Officer, 14 July 2015