Richard Veit (Department of Biology, College of Staten Island, New York, USA) and Nancy Harrison have reviewed interactions between seabirds, including procellariiforms, and other marine predators in the peer-reviewed and open-access journal Frontiers in Ecology and Evolution.

“Our review here shows that interspecific foraging associations among seabirds and other top-level marine predators are an essential component of the life histories of these organisms influence the population growth of the constituent species, and therefore the community structure of the marine systems in which they live. The mixed-species associations of procellariids, and their associations with other predators such as marine mammals, are likely to be of critical importance in structuring the ecosystems in the Southern Ocean, South Atlantic and South Pacific.”

The paper’s commencing passage follows:

“There is increasing recognition of the importance of “positive interactions” among species in structuring communities. For seabirds, an important kind of positive interaction is the use of birds of the same species, birds of other species, and other marine predators such as cetaceans, seals and fishes as cues to the presence of prey. The process by which a single bird uses, say, a feeding flock of birds as a cue to the presence of prey is called “local enhancement” or “facilitation.” There are subtly different uses of each of these terms, but the issue we address here is the ubiquity of positive interactions between seabirds and other marine predators when foraging at sea, and whether as a result of their associations the feeding success, and therefore presumably the fitness, of individual seabirds is increased. If this contention is true, then it implies that conservation of any one species of seabird must take into consideration the status and possible conservation of those species that the focal species uses as a cue while foraging. For example, conservation of great shearwaters (Ardenna gravis), which often feed over tuna (e.g., Thunnus) schools, should take in to consideration conservation of tuna. Ecosystem management depends on understanding the importance of such processes; the loss of biodiversity, and the consequent threat to foraging success, may be a substantial threat to the stability of marine ecosystems.”

Black-browed Albatrosses are known to follow Killer Whales in the Southern Ocean (click here)

 Reference:

Veit, R.R. & Harrison, N.M. 2017. Positive interactions among foraging seabirds, marine mammals and fishes and implications for their conservation. Frontiers in Ecology and Evolution, 06 October 2017.  doi.org/10.3389/fevo.2017.00121.

Note: the review omitted the following paper:

Enticott, J.W. 1986. Associations between seabirds and cetaceans in the African sector of the Southern Ocean. South African Journal of Antarctic Research 16: 25-28.

John Cooper, ACAP Information Officer, 29 November 2017

Zuzana Zajková (Dept. Biologia Evolutiva, Ecologia i Ciències Ambientals, Universitat de Barcelona, Barcelona, Spain) and colleagues have published in the journal Marine Ecology Progress Series on at-sea movements of Boyd’s Shearwater Puffinus boydi.

The paper’s abstract follows:

“Despite the proliferation of seabird tracking studies, there is a relative paucity of studies on small tropical seabirds. We present for the first time the distribution and movements of the little-known Boyd’s shearwater Puffinus boydi, a Procellariiform endemic to the Cape Verde Islands. We tracked 28 birds from 2 breeding sites (Ilhéu Raso and Ilhéu de Cima) with geolocator loggers from 2007 to 2012. We also analysed stable isotopes of carbon and nitrogen in the 1st primary (P1), the 6th rectrice (R6) and the 1st (S1) and 8th (S8) secondary feathers to reveal moulting pattern and oceanic isotopic gradients. Birds migrated on average 1452 km westward, to the central Atlantic Ocean (5 to 15°N, 30 to 40°W), where they stayed on average 114 d, from May to August. Boyd’s shearwaters exploited oceanic waters year-round and showed δ¹³C values similar to other oceanic seabird species and δ¹⁵N values indicating the lowest known trophic level among all central Atlantic seabirds. Isotope values in flight feathers suggest most animals moult their P1 and R6 around the breeding ground, whereas all birds moult S1 and S8 at the non-breeding quarters. Correlations of δ¹³C and δ¹⁵N values from S8 with the longitude of the non-breeding area indicate the existence of large-scale isotopic gradients matching those known at baseline levels. Combining geolocator tracking and stable isotope analyses in feathers not only allowed us to describe in detail the annual life cycle and distribution of the species, but also the oceanic isotopic gradients in the tropical Atlantic.”

Reference:

Zajková Z, Militão T. & González-Solís, J. 2017. Year-round movements of a small seabird and oceanic isotopic gradient in the tropical Atlantic.  Marine Ecology Progress Series 579: 169-183.

John Cooper, ACAP Information Officer, 28 November 2017

The interaction of fisheries with non-target species has become a focus of international efforts to improve mitigation measures and reduce mortalities. Following advances in reducing the impacts on marine mammals, marine turtles and seabirds in large-scale fisheries, one of the current challenges relates to small-scale fisheries.

Since 2007 BirdLife International’s Albatross Task Force team in Chile (ATF-Chile) along with the Committee for the Defense of Fauna and Flora (Comité Nacional Pro Defensa de la Flora y Fauna; CODEFF) has worked to develop and promote mitigation measures to reduce the incidental capture of seabirds, including in artisanal purse-seine fisheries. ATF-Chile has demonstrated that mitigation measures such as installing buoys and reducing excess netting can reduce entanglements.

ATF-Chile’s work has been possible with the support and experience of the manufacturers of fishing nets and the owners and crews of small-scale purse-seine vessels. These include the Syndicate of Purse Seine Fishermen in Coronel (Sindicato de Trabajadores Independientes Pescadores, Armadores y Ramas Afines de la Pesca Artesanal de Coronel; SIPESMAFESA) and the National Confederation of Artisanal Fishermen of Chile (Confederación Nacional de Pescadores Artesanales de Chile; CONAPACH) involving 120 000 fishers.

The workshop, held in the port of Valparaíso this month with the support of CONAPACH, brought together researchers, FAO representatives, fishers and citizens to consider mitigation initiatives in purse-seine fisheries. The meeting was attended by the NGOs Prodelphinus from Peru and Oikonos, which studies the globally Vulnerable Pink-footed Shearwater Ardenna creatopus, a species known to interact with purse-seine fisheries.

AAttendees at the workshop listen to presentations, photographs by Patricio Ortiz

Pink-footed Shearwater, photograph by Peter Hodum

The workshop considered it was necessary to promote the implementation of mitigation measures to reduce bycatch of seabirds and other non-target species to ensure the performance and continuity of the fisheries. It was also agreed that the development and testing of potential mitigation measures should include all actors in the fisheries. Among these, fishermen are considered key to achieving consensus towards the viability and implementation of and compliance with mitigation measures.

ATF-Chile acknowledges the support of the National Fish and Wildlife Foundation (NFWF) and the Royal Society for the Protection of Birds (RSPB), as well as the Chilean fishermen unions (especially SIPESMAFESA) and net manufacturers (such as Kranet Services). Joe Jeffcoate and Oli Yates are thanked for their inputs.

Cristián G. Suazo, Albatross Task Force – Chile, 27 November 2017

The American Bird Conservancy, Molokai Land Trust, Maui Nui Seabird Recovery Project , Pacific Rim Conservation and The Nature Conservancy of Hawaiʻi are working together to set up a social attraction site for globally Near Threatened Laysan Albatrosses Phoebastria immutabilis on the Hawaiian island of Molokai.  Fourteen adult decoys have been placed in pairs to attract passing birds in the dune restoration site on the Anapuka peninsula within the 695-ha Mokio Preserve on the north-west coast of the island, a locality considered to be “well above any sea level rise projections”.  A vocalization unit has also been installed that broadcasts mating calls that will help attract prospecting birds.

“Creating new high-island colonies of [Laysan] Albatrosses is critically important as 99% of their population nest at less than 2 m above sea level.”

A Laysan Albatross decoy before deployment, photograph by Butch Haase

Looking up.  Laysan Albatross decoys stand ready within the Mokio Preserve on Molokai

The US Fish & Wildlife Service has a documented breeding attempt from a location adjacent to the restoration site. The Molokai Land Trust has documented several landings of Laysan Albatrosses within the restoration site over the past several years and has made many observations of overflights and offshore flights within and near the project location.

The initiative follows an on-going attempt to create a high-level colony in the James Campbell National Wildlife Refuge on the nearby island of Oahu, where translocated Laysan and Black-footed P. nigripes chicks have been hand-reared until fledging (click here).

The site has been fenced to protect it from browsing deer and to deter feral cats and domestic dogs; in addition an active trapping programme targets cats, rats and mongooses. Several other breeding seabird species already benefit from predator control at the Mokio site, including White-tailed Phaethon lepturus and Red-tailed P. rubricauda Tropicbirds and Black Noddies Anous minutus, which nest in caves below the 45-60-m coastal cliffs. Two Black-footed Albatrosses have been seen flying in the vicinity recently so the possibility of attracting them to the restoration exists.

Elsewhere on Molokai, the Wedge-tailed Shearwater Ardenna pacifica colony in the 370-ha Moʻomomi Preserve (established in 1988 by the Nature Conservancy of Hawai’i) has increased from two nests in 1999 to nearly 1500 nests and more than 3200 birds (view a video). Control efforts with live traps prevent feral cats, rats and mongooses from preying on shearwater eggs, chicks and adults in the preserve. The preserve is also fenced against Axis Deer Axis axis, dogs and cats. Monitoring of the shearwater population over the last three years includes banding breeding adults and fledglings removed from their burrows (click here).

A Wedge-tailed Shearwater chick removed from its burrow for banding in the Mo`omomi Preserve, photograph courtesy of the Molokai Land Trust

With thanks to William ‘Butch’ Haase, Molokai Land Trust, Hannah Nevins, American Bird Conservancy and Lindsay Young, Pacific Rim Conservation.

John Cooper, ACAP Information Officer, 24 November 2017