The 2017 Intersessional Meeting of the International Commission for the Conservation of Atlantic Tunas (ICCAT) Sub-committee on Ecosystems (SC-ECO) was held in Madrid, Spain, from 10-14 July 2017. The Albatross and Petrel Agreement was represented by Anton Wolfaardt, Convenor of its Seabird Bycatch Working Group.

The previous intersessional meeting of ICCAT’s SC-ECO took place in September 2016, at which the latest (current) ACAP best-practice advice for mitigating seabird bycatch in pelagic longline fisheries was presented, together with a paper outlining the work being progressed to develop ACAP bycatch indicators and a reporting framework. At its 2016 meeting, the SC-ECO recommended that ICCAT’s Supplemental Recommendation on Reducing Incidental Bycatch of Seabirds in ICCAT Longline Fisheries (Rec 11-09) be updated to conform with the revised ACAP advice on line weighting. The SC-ECO acknowledged the updated advice from ACAP on the addition of the two hook-shielding devices as stand-alone best-practice measures.

However, given the novel nature of these measures, and that the source papers used by ACAP to conduct their assessment are still in the process of being peer-reviewed for publication, the SC-ECO was of the view that it is premature at this point to recommend their inclusion in the list of available seabird mitigation measures for ICCAT fisheries.

Because there has not been a subsequent ACAP meeting since the 2016 SC-ECO meeting, and the ACAP advice presented to the 2016 meeting of ICCAT’s SC-ECO remains current, no formal ACAP papers were presented at the 2017 meeting. However, a number of papers pertaining to seabird bycatch were presented by ICCAT Parties and other organisations, and discussed at the meeting. These included papers providing updated estimates of seabird bycatch for some ICCAT fisheries, results from ongoing research into the efficacy of seabird bycatch mitigation measures, the use of bill-length measurements of bycaught birds as a tool to distinguish species in the wandering albatross Diomedea species complex, updates from initiatives underway to assess seabird bycatch associated with ICCAT and other tuna fisheries, and results from a recent analysis of the overlap of albatrosses from South Georgia (Islas Georgias del Sur)* and ICCAT fisheries, the latter confirming the importance of the ICCAT area for South Georgia (Islas Georgias del Sur)* albatrosses. Many of these initiatives are ongoing, and will help contribute to a review of Rec 11-09. Some of these issues will also be discussed at the forthcoming meeting of ACAP’s Seabird Bycatch Working Group (SBWG8) to be held in Wellington, New Zealand this September. The intention is to develop updated inputs and advice to present to the 2018 intersessional meeting of ICCAT’s SC-ECO, and to other Regional Fisheries Management Organisations.

Yellow-fin Tuna

Anton Wolfaardt, Convenor, ACAP Seabird Bycatch Working Group, 02 August 2017

*A dispute exists between the Governments of Argentina and the United Kingdom of Great Britain and Northern Ireland concerning sovereignty over the Falkland Islands (Islas Malvinas), South Georgia and the South Sandwich Islands (Islas Georgias del Sur e Islas Sandwich del Sur) and the surrounding maritime areas.

Julien Collet (Centre d’Etudes Biologiques de Chizé, France) and colleagues have published in the journal Behavioral Ecology on differences in the attraction levels of two albatross species to fishing vessels.

The paper’s abstract follows:

“Anthropogenic food resources have significantly modified the foraging behavior of many animal species. They enhance large multi-specific aggregations of individuals, with strong ecological consequences. It is challenging to predict how individuals or species can differ in their reaction to these resources. For instance, there are wide variations in seabird species abundance behind fishing boats, and individual variations in interaction rates. Whether this is reflecting variations in fine-scale encounter rates or rather variations in attraction strength is poorly quantified. Here we compare the response of Wandering (WA) and Black-browed (BBA) albatrosses to fishing boats operating in sub-Antarctic waters. We use GPS tracking data from both birds and boats (Vessel Monitoring System). Attraction distances were similar between the 2 species (up to 30 km). BBA foraged further from fishing grounds and encountered boats less frequently than WA, but once they encountered a boat BBA were more strongly attracted (80% vs. 60% chance) and had a higher level of active interaction, compared to WA. Furthermore, in the absence of boats, BBA were rarely observed foraging over the habitat where the fisheries mainly operate, in contrast with WA. We thus report qualitative and quantitative differences in the response of these 2 species to the same fishing fleet. WA, the larger, more dominant and more generalist species was unexpectedly less attracted to fishing vessels. Comparing our results with previously published studies, we suggest that energetic requirements of individuals may be a crucial predictor for assessing risks of interactions with anthropogenic food resources.”

A Wandering Albatross at sea, photograph by John Chardine

Reference:

Collet, J., Patrick, S.C. & Weimerskirch, H. 2017. A comparative analysis of the behavioral response to fishing boats in two albatross species. Behavioral Ecology DOI: https://doi.org/10.1093/beheco/arx097.

John Cooper, ACAP Information Officer, 01 August 2017

From time to time ACAP Latest News has reported on progress towards the eradication of introduced rats on Australia’s Lord Howe Island, a World Heritage breeding home to burrowing petrels and shearwaters (click here).

The Rodent Eradication Program proposes to use the rodenticide brodifacoum to eradicate both rats and mice on the island. The rodenticide, in the form of Pestoff 20R, would be distributed by aerial baiting, hand distribution and in bait stations. A report on a human health risk assessment of the proposed eradication exercise has now been released (click here).

The assessment considers that the use of brodifacoum on the island is not likely to result in adverse health effects to humans.  These findings will have implications for rodent eradications on other inhabited seabird islands, such as Pitcairn and Tristan da Cunha.

Flesh-footed Shearwaters are at risk to rodents on Lord Howe Island, photograph by Barry Baker

“…other relevant approvals processes will look at environmental outcomes (effect of brodifacoum on non-rodent species), likelihood of success of the eradication, and approval of helicopter operations during the Rodent Eradication Program. The results of these approvals and the recommendations of this report will be considered by the Lord Howe Island Board.”

John Cooper, ACAP Information Officer, 31 July 2017

Rory Gibb (Institute of Zoology, Zoological Society of London, Regent's Park, UK) and colleagues have published in the Journal of the Royal Society Interface on flight patterns in Manx Shearwaters Puffinus puffinus.

The paper’s abstract follows:

“Global wind patterns affect flight strategies in many birds, including pelagic seabirds, many of which use wind-powered soaring to reduce energy costs during at-sea foraging trips and migration. Such long-distance movement patterns are underpinned by local interactions between wind conditions and flight behaviour, but these fine-scale relationships are far less well-understood. Here we show that remotely-sensed ocean wind speed and direction are highly significant predictors of soaring behaviour in a migratory pelagic seabird, the Manx shearwater (Puffinus puffinus). We used high-frequency GPS tracking data (10Hz) and statistical behaviour state classification to identify two energetic modes in at-sea flight, corresponding to flap-like and soar-like flight. We show that soaring is significantly more likely to occur in tailwinds and crosswinds above a wind speed threshold of around 8ms-1, suggesting that these conditions enable birds to reduce metabolic costs by preferentially soaring over flapping. Our results suggest a behavioural mechanism by which wind conditions may shape foraging and migration ecology in pelagic seabirds, and thus indicate that shifts in wind patterns driven by climate change could impact this and other species. They also emphasise the emerging potential of high-frequency GPS biologgers to provide detailed quantitative insights into fine-scale flight behaviour in free-living animals.”

Manx Shearwater, photograph by Nathan Fletcher

See a popular article on the paper here.

Reference:

Gibb, R., Shoji, A., Fayet, A.L., Perrins, C.M., Guilford, T. & Freeman, R. 2017.  Remotely sensed wind speed predicts soaring behaviour in a wide-ranging pelagic seabird.  Journal of the Royal Society Interface DOI: 10.1098/rsif.2017.0262.

John Cooper, ACAP Information Officer, 28 July 2017