Mark Bolton (RSPB Centre for Conservation Science, Royal Society for the Protection of Birds, Sandy, U.K.) and colleagues have reviewed free access in the ornithological journal Ibis  inter‐colony segregation of foraging areas of seabirds, including of five species (eight studies) of ACAP-listed albatrosses and petrels (in the genera Phoebastria, Phoebetria, Thalassarche and Macronectes) and four species (eight studies) of shearwaters (Ardenna, Calonectris, Puffinus).

The paper’s abstract follows:

“Understanding the determinants of species’ distributions is a fundamental aim in ecology and a prerequisite for conservation but is particularly challenging in the marine environment. Advances in bio‐logging technology have resulted in a rapid increase in studies of seabird movement and distribution in recent years.  Multi‐colony studies examining the effects of intra‐ and inter‐colony competition on distribution have found that several species exhibit inter‐colony segregation of foraging areas, rather than overlapping distributions. These findings are timely given the increasing rate of human exploitation of marine resources and the need to make robust assessments of likely impacts of proposed marine developments on biodiversity. Here we review the occurrence of foraging area segregation reported by published tracking studies in relation to the density‐dependent hinterland (DDH) model, which predicts that segregation occurs in response to inter‐colony competition, itself a function of colony size, distance from the colony and prey distribution. We found that inter‐colony foraging area segregation occurred in 79% of 39 studies. The frequency of occurrence was similar across the four seabird orders for which data were available, and included species with both smaller (10–100 km) and larger (100–1000 km) foraging ranges. Many predictions of the DDH model were confirmed, with examples of segregation in response to high levels of inter‐colony competition related to colony size and proximity, and enclosed landform restricting the extent of available habitat. Moreover, as predicted by the DDH model, inter‐colony overlap tended to occur where birds aggregated in highly productive areas, often remote from all colonies. The apparent prevalence of inter‐colony foraging segregation has important implications for assessment of impacts of marine development on protected seabird colonies. If a development area is accessible from multiple colonies, it may impact those colonies much more asymmetrically than previously supposed. Current impact assessment approaches that do not consider spatial inter‐colony segregation will therefore be subject to error. We recommend the collection of tracking data from multiple colonies and modelling of inter‐colony interactions to predict colony‐specific distributions.”

Globally Critically Endangered Waved Albatross Phoebastria irrorata in flight, one of the studied ACAP species, photograph by Barry Baker

Reference:

Bolton, M., Conolly, G., Ewan, M.C., Wakefield, D. & Caldow, R. 2018.  A review of the occurrence of and the implications for marine environmental impact assessment.  Ibis doi.org/10.1111/ibi.12677.

John Cooper, ACAP Information Officer, 15 November 2018

A baited Hookpod ready for release, photograph by Fabiano Pepes

The spring-loaded polycarbonate Hookpod is a hook-shielding device that is attached to the branch lines of a pelagic longline, encapsulating the barbed end of the baited hook. Once it reaches a depth of at least 10 m a pressure-activated mechanism in the pod causes it to open, releasing the hook and exposing its barb.

Illustration from Albatross Task Force - Brazil

Trials conducted in Australia, Brazil and South Africa, as published in the journal Animal Conservation last year, have shown that the Hookpod can reduce seabird bycatch by up to 95%, reducing seabird bycatch to rates of 0.01 birds/1000 hooks and without affecting the catch of target fish species.  However, it is thought that the seabird catch rate can be reduced even further if the Hookpod is released at a greater depth, especially in areas with high densities of medium-sized diving petrels (such as the globally Vulnerable White-chinned Petrels Procellaria aequinoctialis) capable of retrieving baits from depths below 10 m. As a consequence, trials of a new Hookpod design that releases hooks at a 20-m depth are planned to commence in the Brazilian pelagic longline fishery this month, continuing for a year.

It is intended that four Brazilian pelagic longliners fitted with the new Hookpods will be compared to vessels from the same fleet, using standard gear to fish in the same area and season.

“This will involve a huge coordinated effort of dedicated [Albatross Task Force] instructors and Projeto Albatroz observers, our strategic partner in Brazil, gathering data onboard vessels with Hookpods as well as standard vessels, simultaneously” (click here).

The Brazilian trials have received support through ACAP's Small Grant scheme this year; following the Agreement adding the Hookpod to its list of best-practice measures for mitigating seabird bycatch in pelagic longline fisheries.

Information from Dimas Gianuca, Albatross Task Force team leader in Brazil.

Read more about Hookpods here and here.

Reference:

Sullivan, B.J., Kibel, B., Kibel, P., Yates, O., Potts, J.M., Ingham, B., Domingo, A., Gianuca, D., Jiménez, S., Lebepe, B., Maree, B.A., Neves, T., Peppes, F., Rasehlomi^, T., Silva-Costa, A. & Wanless, R.M. 2017.  At-sea trialling of the Hookpod: a ‘one-stop’ mitigation solution for seabird bycatch in pelagic longline fisheries.  Animal Conservation DOI: 10.1111/acv.12388.

John Cooper, ACAP Information Officer, 14 November 2018

Airam Rodríguez (Conservation Department, Phillip Island Nature Parks, Cowes, Victoria, Australia) and colleagues have published in the journal Environmental Pollution on plastic pollution in the Short-tailed Shearwater Ardenna tenuirostris (Least Concern)

The paper’s abstract follows:

“Despite the increase of literature on seabird plastic ingestion in recent years, few studies have assessed how plastic loads vary according to different sampling methods. Most studies use necropsies of seabirds with a natural cause of death, e.g. beached or predated [sic], to determine plastic loads and monitor marine debris. Sampling naturally dead seabirds may be biased as they have perished because of their intrinsic factors, e.g. poor body condition, high parasite loads, sickness or predation, affecting estimates of plastic loads. However, seabirds killed accidentally may be more representative of the population. Here, we used the short-tailed shearwater Ardenna tenuirostris to test different sampling methods: naturally beached fledglings and accidentally road-killed fledglings after being attracted and grounded by artificial lights. We compared plastic load, body condition, and feeding strategies (through using feathers’ δ¹³C and δ¹⁵N isotope niche) between beached and road-killed fledglings. Beached birds showed higher plastic loads, poorer body condition and reduced isotopic variability, suggesting that this group is not a representative subsample of the whole cohort of the fledgling population. Our results might have implications for long-term monitoring programs of seabird plastic ingestion. Monitoring plastic debris through beached birds could overestimate plastic ingestion by the entire population. We encourage the establishment of refined monitoring programs using fledglings grounded by light pollution if available. These samples focus on known cohorts from the same population. The fledgling plastic loads are transferred from parents during parental feeding, accumulating during the chick-rearing period. Thus, these fledglings provide a higher and valuable temporal resolution, which is more useful and informative than unknown life history of beached birds.”

Short-tailed Shearwater at sea, photograph by Kirk Zufelt

Reference:

Rodríguez, A., Ramírez, F., Carrasco, M.N. & Chiaradia, A. 2018.  Seabird plastic ingestion differs among collection methods: examples from the short-tailed shearwater.  Environmental Pollution 243B: 1750-1757.

John Cooper, AAP Information Officer, 13 November 2018

The Marsh Award for Marine Conservation Leadership is made by the Marsh Christian Trust (MCT) in partnership with Fauna and Flora International (FFI) and “recognises people and organisations who are having a profound impact on marine conservation activities in the areas where they operate”.

The Award celebrates those who have been active in their communities, highlighting local leaders or organisations making a particularly special contribution to marine conservation through FFI’s organisational aims: securing the future of key threatened habitats and species; addressing root causes of biodiversity loss; assisting others in delivering conservational gains.

One of the two Marsh Marine Conservation Leadership Award recipients for 2018 is Leandro (Leo) Tamini of Albatross Task Force - Argentina, who has invented the Tamini Tabla (Tamini Table), a device that has the potential to reduce seabird mortality due to collision with trawl cables or warps.

A Tamini Tabla gets fitted for deployment on a bird-scaring line aboard a trawler, photograph by Leo Tamini

Luis reports in a BirdLife International news item: “One of my goals when I began working with the Albatross Task Force was to increase the usage of bird-scaring lines. This method [which involves using colorful streamers to ward birds away from trawl cables or longline hooks] is one of the simplest and most economical ways to reduce the instances of birds crashing into trawling cables. However, these lines can become tangled in the trawl cables, wearing them out and causing problems for fishing crews.  The solution was to design something that would weigh the bird-scaring lines down, to maintain the tension and keep the lines separated from the trawl cables. After pondering on the question for a while, and discarding a few ideas that wouldn’t work for technical reasons, I thought that we should try doing something like a miniature surfboard, with a keel at about 45 degrees to make sure the board stayed even. With the help of some crew I was able to put together a prototype from materials found on board the vessel. We tested it, and incredibly, it worked great! The lines were more taut and went out at about a 20 degree angle away from the vessel” (click here).

John Cooper, ACAP Information Officer, 12 November 2018