Agreement on the Conservation of Albatrosses and Petrels

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Read about recent developments and findings in procellariiform science and conservation relevant to the Agreement on the Conservation of Albatrosses and Petrels in ACAP Latest News.

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Wandering Albatrosses at the Crozets: individual variation in susceptibility to longline fishing

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

Improving recording of seabird mortality on longliners: first WCPFC E-Reporting and E-Monitoring Intersessional Working Group Meeting held in Fiji

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

Acoustic monitoring of seabird populations and seabird breeding islands to be discussed on Twitter this weekend

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

Feral cats prey upon Yelkouan Shearwaters in the French Hyères Archipelago

Elsa Bonnaud (Unité Ecologie, Systématique et Evolution, Université Paris-Sud, Orsay, France) and colleagues have published in the journal Biological Invasions on feral Domestic Cats Felis catus preying upon Yelkouan Shearwaters Puffinus yelkouan in the French Mediterranean.

The paper’s abstract follows:

“Domestic cats are one of the most widespread predators on islands worldwide and are responsible for numerous reductions and extinctions of species on islands.  The three main islands of the Hyères Archipelago house one of the largest colonies of the Mediterranean endemic Yelkouan shearwater Puffinus yelkouan that has recently been up-listed by the IUCN to ‘vulnerable’.  The main objectives of this study were to assess the diet of cats and to study the effect of cat predation on Yelkouan shearwater populations at the archipelago scale. The diet of cats was studied using scat analyses according to years and seasons for each island.  Simultaneously, Yelkouan shearwater breeding success was monitored during a period of 8 years on Port-Cros and Porquerolles, and 3 years on Le Levant.  Descriptive analyses and GLM were used to compare data gathered on each island.  At the archipelago scale, cats preyed strongly upon introduced mammals and shearwaters.  Surprisingly, large differences appeared in cats’ diet according to the island considered.  The Yelkouan shearwater was the primary prey of cats on Le Levant, but secondary on Port-Cros and Porquerolles.  Cat predation was mainly concentrated during the shearwater prospecting period, when birds arrive at the colonies and look for a mate (if they are not already paired) and a burrow before breeding.  Consequently cat impact was low on shearwater breeding success.  However, this study demonstrates that the cat management conducted on Port-Cros was positive for fledging success.  The successful cat eradication on Port-Cros supports the need to continue working for Yelkouan shearwater conservation with Le Levant as a priority, because this is where the colonies are largest and predation on Yelkouan shearwaters is very high.”

 

At risk to cats: a Yelkouan Shearwater in its burrow, photograph by Jerome Lagrand 

Reference:

Elsa Bonnaud, E., Palmas, P., Bourgeois, K., Ollier, S. Zarzoso-Lacoste, D. & Vidal, E. 2015.  Island specificities matter: cat diet differs significantly between islands of a major breeding archipelago for a vulnerable endemic seabird.  Biological Invasions DOI 10.1007/s10530-015-0921-4.

John Cooper, ACAP Information Officer, 13 July 2015

Modelling demographic rates for White-capped Albatrosses

Jim Roberts and colleagues (National Institute of Water & Atmospheric Research Ltd, Christchurch, New Zealand) have tabled a draft background report to last month’s meeting of the Conservation Services Programme (CSP) of New Zealand’s Department of Conservation that considers estimating demographic rates for White-capped Albatrosses Thalassarche steadi.

The report’s Executive Summary follows:

“Disappointment Island, within the Auckland Islands group, supports over 70,000 breeding pairs of white-capped albatrosses Thalassarche cauta steadi annually, the largest colony of New Zealand’s most abundant albatross species.  This species interacts with commercial fisheries and ranks highly within the Level 2 Seabird Risk Assessment process, but with a relatively high level of uncertainty around the estimate of adult survival.  A study was undertaken to assess the effect of alternative mark-recapture sampling approaches to a potential mark-resighting study of white-capped albatross on the estimation of demographic rates.

A data simulator was used to create dummy mark-resighting observations for a single banding year with alternative scenarios of: banded sample size (150, 300 or 600 breeding individuals); number of subsequent consecutive resighting years (2, 3, 4, 5 or 10 years); and resighting probability of breeders (0.6 or 0.4) and non-breeders (0.0 or 0.1).

The SeaBird demographic modelling software was then used to determine variability in the estimates of survival and breeding rate using the dummy mark-resighting observations.  This assessment assumed that demographic rates were constant with respect to year and age and variability of demographic rates of wild populations are likely to be greater than those obtained by this assessment.  Increasing the banded sample size from 150 to 600 individuals led to an increase in the precision (c.v.) of annual survival breeding rate estimates.

With an input survival rate of 0.95 and a banded population of 150 individuals, the range of survival estimates was wide with 5 years of resighting effort (range from 0.91-0.99, x̅ = 0.95), though was much narrower with 10 years of resighting effort (0.93-0.96, x̅ = 0.95).  With a banded sample size of 600 individuals, the range of survival estimates was narrow with 5 years of resighting effort (0.93-0.97, x̅ = 0.95).

The precision of demographic rate estimates was not greatly affected by reducing the resighting probability of breeders from 0.6 to 0.4, though reducing the resighting probability of non-breeders from 0.10 to 0.00 produced imprecise estimates that were for some samples very different from input values.

To produce estimates of demographic rates that would be suitably precise for risk assessment purposes, this data simulation approach indicates that resighting effort over 5-10 years would be required subsequent to banding of a population between 150-600 individuals.  In a wild population, demographic rates are likely to change through time, so that greater sampling effort (in terms of banded individuals, number of resighting years or even resighting effort) may be required.”

 

White-capped Albatross, photograph by Graham Parker

Reference:

Roberts, J., Doonan, I. & Thompson, D. 2015.  Demographic Rate Estimation of White-capped Albatross Simulation Modelling.  Draft Copy Prepared for Department of Conservation June 2015.  Wellington: National Institute of Water & Atmospheric Research Ltd.  12 pp.

John Cooper, ACAP Information Officer, 12 July 2015

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