The Looming-Eyes Buoy deters seaducks, photograph by Andres Kalamees

Yann Rouxel (BirdLife International Marine Programme, c/o the Royal Society for the Protection of Birds Scotland, Glasgow, UK) and colleagues have published open access in the journal Royal Society Open Access on developing a novel deterrent for seabirds in gill-net fisheries.

The paper’s abstract follows:

“Bycatch of seabirds in gillnet fisheries is a global conservation issue with an estimated 400 000 seabirds killed each year. To date, no underwater deterrents trialled have consistently reduced seabird bycatch across operational fisheries. Using a combination of insights from land-based strategies, seabirds' diving behaviours and their cognitive abilities, we developed a floating device exploring the effect of large eyespots and looming movement to prevent vulnerable seabirds from diving into gillnets. Here, we tested whether this novel above-water device called ‘Looming eyes buoy' (LEB) would consistently deter vulnerable seaducks from a focal area. We counted the number of birds present in areas with and without LEBs in a controlled experimental setting. We show that long-tailed duck Clangula hyemalis abundance declined by approximately 20–30% within a 50 m radius of the LEB and that the presence of LEBs was the most important variable explaining this decline. We found no evidence for a memory effect on long-tailed ducks but found some habituation to the LEB within the time frame of the project (62 days). While further research is needed, our preliminary trials indicate that above-water visual devices could potentially contribute to reduce seabird bycatch if appropriately deployed in coordination with other management measures.”

Read popular counts here and here.

Reference:

Rouxel, Y., Crawford, R., Cleasby, I.R., Kibel, P., Owen, E., Volke, V., Schnell, A.K. & Oppel, S. 2021.  Buoys with looming eyes deter seaducks and could potentially reduce seabird bycatch in gillnets.  Royal Society Open Access  doi.org/10.1098/rsos.210225.

John Cooper, ACAP Information Officer, 12 May 2021

"Southern Ocean Wanderer" by Brett Jarrett

A.M. Heswall (School of Biological Sciences, The University of Auckland, New Zealand) and colleagues report in the journal Marine Biology on a study attempting to correlate seabird size with bycatch.

The paper’s abstract follows:

“Many animals have sensory biases towards signals or cues that typically provide some fitness benefit. Sensory traps occur when other species or anthropogenic sources produce similar signals or cues but responding is no longer adaptive and can impose significant costs or even death. Bycatch of seabirds by fishing boats has devastating impacts, causing hundreds of thousands of seabird deaths per annum. Here, we explore whether fishing vessels are acting as a sensory trap, inadvertently targeting seabirds with certain life-history traits or larger skeletal or sensory structures. We surveyed the literature to compare seabird order, diet, wingspan, body size, and nesting preference (surface or burrow) of 70 seabirds with varying numbers of reported bycatch in one of the world’s most important regions for seabird breeding, in northern Aotearoa New Zealand. We also examined the skeletal and sensory measurements of six seabirds that co-occur spatially in this region, but have different numbers of reported bycatch and indices of bycatch risk. The literature survey revealed that the Charadriiformes and the Sphenisciformes were the most vulnerable groups (p = 0.01), especially to surface longline fisheries.  There were no correlations with diet and foraging behaviour, but surface nesting seabirds and those with larger bodies and wingspans were at a greater risk of becoming bycatch. Skeletal measurements show that species with higher bycatch also have relatively larger skulls, bills and wings, eye sockets and nostrils (relative to body size) (p < 0.05). This suggests that having a larger overall body size and longer protruding body parts is a primary risk factor, but that species with relatively more sensitive sensory systems likely have even more acute bycatch risk. Considering fishing vessels as sensory traps provides a context to explore the multiple interconnecting factors of sensory sensitivity, sensory bias, behaviour and morphology.”

With thanks to Janine Dunlop, Niven Librarian, FitzPatrick Institute, University of Cape Town.

Reference:

Heswall, A.M., Friesen, M.R., Brunton Martin, A.L. & Gaskett, A.C. 2021.  Seabird bycatch risk correlates with body size, and relatively larger skulls, bills, wings and sensory structures.  Marine Biology doi.org/10.1007/s00227-021-03873-4.

John Cooper, ACAP Information Officer, 11 May 2021

Each exposed rectangle represents 100 hectares of Marion Island funded to date

The “Sponsor a Hectare” campaign of the Saving Marion Island's Seabirds Mouse-free Marion Project has reached its first milestone.  A total of a little over 2012 hectares generating over two million South African Rands has now been sponsored.  Why this exact figure?  Well, this is the size of New Zealand’s Antipodes Island from which an estimated 200 000 introduced House Mice Mus musculus were successfully eradicated by a helicopter bait drop in 2016, with confirmation of success coming two years later.

The cost of the Antipodes Island Million Dollar Mouse project was partially covered by a crowd-funding exercise that aimed to raise a million New Zealand Dollars from non-government sources.  To encourage contributions from Kiwis (and from outside New Zealand) the project’s website and Facebook page regularly updated a map of the islands with crossed-out mice signifying progress.  With this as inspiration, ACAP’s Information Officer proposed a similar campaign for Marion Island to BirdLife South Africa, which is partnering with the South African Department of Forestry, Fisheries and the Environment to rid the island of its mice in 2013.

Four mice gone!  Early days with Antipodes Island’s Million Dollar Mouse campaign

ACAP Latest News reached out to New Zealand Department of Conservation’s Stephen Horn who as Project Manager led the Antipodes eradication (and is a member the M-FM’s Scientific and Technical Advisory Group).  In reply he writes “The eradication of mice from Antipodes Island was powered by people contributing to the project.  School kids, businesses, individuals, groups, and everyday people getting involved were the reason the project got off the ground and succeeded.  With mice gone, land birds such as snipe and pipits are thriving and there are signs of burrowing seabirds recovering from the extensive damage caused by mice.  I was privileged to lead the project on Antipodes Island and help people reach their goal and save its precious wildlife.  From the Antipodes Islands in New Zealand’s sub-Antarctic region to South Africa’s remote Marion Island the challenges are immense but worthy and every dollar and hectare count.  I urge you to get involved to provide seabirds and the unique wildlife on Marion Island somewhere safe to breed and help undo the damage caused by mice”.

Stephen Horn on Macquarie Island

So what is the next campaign challenge for Marion’s Sponsor a Hectare initiative?  Surely it has to be 6520 ha funded, the size of Gough Island in the South Atlantic, which the UK’s Gough Island Restoration Programme aims to rid of its of its albatross-killing mice in a few months’ time.  Would be good to reach this second milestone by the time the last helicopter load of bait is dropped on Gough this year, but with the aim to crowd fund 30 000 ha there will still be a long way to go!

Follow the Antipodes Island eradication to ultimate success in the archives of ACAP Latest News.

With thanks to Stephen Horn.

John Cooper, ACAP Information Officer, 10 May 2021

"Examples of Flesh-footed Shearwater boluses containing anthropogenic debris on Lord Howe Island. Panels A/B and C/D show the same bolus intact (top
panel) and separated into components in the lab (bottom panel). Photo: S. Stuckenbrock".  From the publication

Alex Bond (Bird Group, The Natural History Museum, Tring, UK) and colleagues have published in the Marine Pollution Bulletin showing that 100% of examined boluses from Flesh-footed Shearwaters Ardenna carnepeis (Near Threatened) from Australia's Lord Howe Island contained plastic items.

The paper’s abstract follows:

“Plastic production and pollution of the environment with plastic items is rising rapidly and outpacing current mitigation measures.  Success of mitigation actions can only be determined if progress can be measured reliably through incorporation of specific, measurable targets.  Here we evaluate temporal changes in the amount and composition of plastic in boluses from Flesh-footed Shearwaters during 2002–2020 and assess their suitability for measuring progress against national and international commitments to reduce plastic pollution.  Plastic in the shearwater boluses showed a generally decreasing pattern from 2002 to 2015 and increasing again to 2020.  The colour and type of plastics in boluses was comparable to items recovered from live and necropsied birds, but a much smaller sample size (~35 boluses/year) was required to detect changes in plastic number and mass over time. We therefore suggest shearwater boluses are a low-effort, high-statistical power monitoring tool for quantifying progress against environmental policies in Australia.”

The problem: Flesh-footed Shearwaters ingest large amounts of plastic, photograph by Ian Hutton

With thanks to Janine Dunlop, Niven Librarian, FitzPatrick Institute, University of Cape Town.

Reference:

Bond, A.L., Hutton, I. & Lavers, J.L. 2021.  Plastics in regurgitated Flesh-footed Shearwater (Ardenna carneipes) boluses as a monitoring tool.  Marine Pollution Bulletin doi.org/10.1016/j.marpolbul.2021.112428.

John Cooper, ACAP Information Officer, 09 May 2021