The Kilauea Point Natural History Association reports via Facebook from the Hawaiian island of Kauai: “The Laysan Albatross [Phoebastria immutabilis] (mōlī in Hawaiian) nesting survey took place at Kīlauea Point [National Wildlife Refuge] in mid-December.  A total of 121 active nests were [sic] counted throughout the refuge.  May they have a very successful nesting season this year!”

Note that the refuge is currently closed to the public due to the US Government partial shutdown. “National Wildlife Refuges are operated by the US Fish and Wildlife Service which falls under the Dept. of Interior. Until the federal appropriations bill passes, the Dept. of Interior (along with some other federal agencies) will remain closed.”

A Laysan Albatross with its egg on Kauai, photograph by Hob Osterlund

Meanwhile, over in New Zealand at the Taiaroa Head mainland colony of globally Endangered Northern Royal Albatrosses Diomedea sanfordi  news seems good for the 2018/19 breeding season, as reported in a local newspaper:

“High fertility rates among Taiaroa Head albatross eggs after a bumper laying season means the colony is still on track for record chick numbers.  From an all-time high of 51 eggs at the colony this year, 43 have been found to be viable by staff [by candling and weighing to detect a drop as the live embryo uses up fluid in the egg - click here].

Otago Peninsula Trust marketing manager Sophie Baker said it was now hoping for colder weather than last year so no more died before hatching.  Of 33 eggs last season only 13 chicks fledged due to continued heat.  "While everybody is praying for a lovely new year, we're hoping `please let it be a little bit chilly'. The proportion of fertile eggs this year "sounded about right" compared to what was expected, she said.

Last month the centre replaced its irrigation system, used to cool the birds on hot dry days, so pipes could deal with extreme weather conditions.  It also had new egg-handling and supplementary feeding equipment to improve albatross management.  Twenty-one pairs had returned from last season and 147 individuals were seen overall.  The eggs are expected to hatch late January and early February”.

The water sprays got tested this weekend, when the temperature reached 30C and incubating birds commenced panting to lose heat.

A  Northern Royal Albatross pair at Taiaroa Head

John Cooper, ACAP Information Officer, 07 January 2019

Sebastián Jiménez (Laboratorio de Recursos Pelágicos, Dirección Nacional de Recursos Acuáticos, Montevideo, Uruguay) and colleagues have published in the journal Animal Conservation on the effectiveness of branch line weighting in pelagic longline fisheries.

The paper’s abstract follows:

“Substantial numbers of seabirds are bycaught each year in pelagic longline fisheries. Increasing the sink rate of baited hooks by reducing the distance between the hook and the weight of the branch lines (leader length) has enormous potential to mitigate this bycatch. Here, we test the effect of reducing the leader length on seabird attacks on baited hooks and bycatch rates plus the effect on fish catch rates on the Uruguayan slope. Two branch line configurations were tested: a control treatment (CT) of the standard branch lines used in the Uruguayan fishery, with 75 g swivels on 4.5 m leaders; and two experimental treatments (ET) consisting of branch lines with either a 60 g or 65 g weight on 1 m leaders. Seabird attacks were assessed during 34 daylight longline sets (100–150 hooks each) without a bird scaring line (BSL) comparing two treatments: CT versus 65 g ET. The fish catch was assessed during 224 paired sections (75 vs. 75 hooks) from 109 fishing sets deployed mostly during the night and with a BSL, comprising 77 pairs of CT versus 60 g ET and 147 pairs of CT versus 65 g ET. The number of primary (231 nvs. 91) and multiple (50 vs. 14) attacks were significantly higher in the CT compared with the 65 g ET respectively. The seabird bycatch rate was 42.5% lower in the 65 g ET than in the CT. The use of branch lines with short leaders did not affect the catch of target species. This study conducted in an area of high bycatch risk provides strong experimental support for the use of branch line weighting to reduce seabird bycatch. Based on the observed bycatch rates, this measure should be implemented in combination with other mitigation measures. The simultaneous use of branch line weighting, a BSL and night setting resulted in zero seabird bycatch.”

With thanks to Sebastián Jiménez.

Reference:

Jiménez, S., Domingo, A. Forselledo, R., Sullivan, B.J. & Yates, O. 2018.  Mitigating bycatch of threatened seabirds: the effectiveness of branch line weighting in pelagic longline fisheries.  Animal Conservation doi:10.1111/acv.12472.

John Cooper, ACAP Information Officer, 04 January 2019

Claude Joiris (Laboratory for Polar Ecology, Saint Restitut, France) and Grant Humphries have published in the journal Advances in Polar Science on seabirds at sea in the Southern Ocean, finding concentrations at oceanic fronts.  The ACAP-listed Salvin’s Albatross Thalassarche salvini was one of the most abundant recorded out of 22 species at frontal zones.

The paper’s abstract follows:

“This article is part of our long-term study on the quantitative at-sea distribution of the marine “upper trophic levels”—seabirds and marine mammals—in polar ecosystems, aiming at quantifying the factors influencing their distribution as well as detecting possible spatial and temporal changes, with special attention to hydrography and to global climate changes. During an expedition of icebreaking RV Polarstern in February 2010, along the North–South transect between New Zealand and the Ross Gyre, off the Ross Sea, 3200 seabirds belonging to 22 identified pelagic species were recorded during 338 half-hour transect counts. Four major hotspots were identified. These were in Sub-tropical Water off New Zealand (up to 300 birds per count), and at the main Southern Ocean fronts: the Sub-Antarctic Front (up to 240 per count), the Antarctic Front (up to 150 per count) and the Polar Front (up to 200 per count), representing the vast majority of recorded seabirds. The most numerous species in the three frontal zones were: prions—mainly slender-billed Pachyptila belcheri—and Salvin’s albatross Thalassarche [cauta ] salvini. The eight more abundant species represented 2650 birds, i.e. more than 80% of the total. A random forest clustering method identified four groups of seabird species occupying similar oceanographic niches.”

Salvin's Albatross at sea, photograph by Aleks Terauds

Joiris, C.R. & Humphries, G.R.W. 2018.  Hotspots of seabirds and marine mammals between New Zealand and the Ross Gyre: importance of hydrographic features.  Advances in Polar Science 29: 254-261.

John Cooper, ACAP Information Officer, 03 January 2019

Ricardo De Paoli‐Iseppi (Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia) and colleagues have published in the journal Molecular Ecology Resources on ageing Short‐tailed Shearwaters Ardenna tenuirostris by analysing their blood.

The paper’s abstract follows:

“Age structure is a fundamental aspect of animal population biology. Age is strongly related to individual physiological condition, reproductive potential and mortality rate. Currently, there are no robust molecular methods for age estimation in birds. Instead, individuals must be ringed as chicks to establish known‐age populations, which is a labour intensive and expensive process. The estimation of chronological age using DNA methylation is emerging as a robust approach in mammals including humans, mice and some non‐model species. Here we quantified DNA methylation in whole blood samples from a total of 71 known‐age Short‐tailed shearwaters (Ardenna tenuirostris) using digital restriction enzyme analysis of methylation (DREAM). The DREAM method measures DNA methylation levels at thousands of CpG dinucleotides throughout the genome. We identified seven CpG sites with DNA methylation levels that correlated with age. A model based on these relationships estimated age with a mean difference of 2.8 years to known age, based on validation estimates from models created by repeated sampling of training and validation data subsets. Longitudinal observation of individuals re‐sampled over 1 or 2 years generally showed an increase in estimated age (6/7 cases). For the first time, we have shown that epigenetic changes with age can be detected in a wild bird. This approach should be of broad interest to researchers studying age biomarkers in non‐model species and will allow identification of markers that can be assessed using targeted techniques for accurate age estimation in large population studies.”

Short-tailed Shearwater, photograph by Kirk Zufelt

Reference:

De Paoli‐Iseppi, R., Deagle, B.E., Polanowski, A.M., McMahon, C.R., Dickinson, J.L., Hindell, M.A. & Jarman, S.N. 2018.  Age estimation in a long‐lived seabird (Ardenna tenuirostris) using DNA methylation‐based biomarkers.  Molecular Ecology Resources doi.org/10.1111/1755-0998.12981.

John Cooper, ACAP Information Officer, 02 January 2019