Chris Jones, an ornithological field worker on World Heritage Gough Island in the South Atlantic, reports to ACAP Latest News of a Critically Endangered Tristan Albatross Diomedea dabbenena chick that has gone blind in both eyes in the long-term study colony in Gonydale this year.

Chris writes “I first noticed that the chick was blind in its left eye on 26 May (so can't confirm if it had this condition since hatching or developed it) when it did not respond to motion on its left side.  It did respond to motion on its right side and the left eye appeared blue and cloudy.  Initially I thought this may be an injury since the chick was off its nest, perhaps blown off by very strong winds during the previous few days.  On a successive check on 6 June, the chick seemed to be blind in both eyes, not responding to any motion (only to sound and touch) and the right eye appeared blue-ish although not to the same extent as the left.”

The 2015 Tristan Albatross chick showing its blind left eye, photographs by Chris Jones

A blind Tristan Albatross chick has been previously photographed in Gonydale on Gough in 2012; this bird drowned in the Gony River (click here).

The 2012 blind Tristan Albatross chick, photographs by Sylvain Dromzée

The 2012 blind chick found dead in the Gony River, photograph by Sylvain Dromzée

It has been suggested that blindness observed in one eye of an adult Laysan Albatross Phoebastria immutabilis could have been caused by avian pox contracted from mosquitoes when the albatross was a young chick (click here).  The two Tristan Albatross chicks did not show signs of other symptoms of avian pox (and mosquitoes do not occur on the island), so the cause(s) of their blindness remains unknown.

John Cooper, ACAP Information Officer, 14 June 2015

Michelle Paleczny (University of British Columbia, Vancouver, Canada) and colleagues have published in the open-access journal PLoS ONE on a global review of monitored seabird populations.  The paper notes the poor conservation status of both the families Diomedeidae (albatrosses) and Procellariidae (petrels and allies).  It states that “…the removal of cats and rats from small islands has been achieved on multiple occasions and been shown to increase local seabird numbers, however undertaking conservation actions for pan-global populations [as for many of the 31 ACAP-listed species], such as reducing oceanic pollution or lowering fishing pressure will be considerably more challenging.”

The paper’s abstract follows:

“Seabird population changes are good indicators of long-term and large-scale change in marine ecosystems, and important because of their many impacts on marine ecosystems. We assessed the population trend of the world’s monitored seabirds (1950–2010) by compiling a global database of seabird population size records and applying multivariate autoregressive state-space (MARSS) modeling to estimate the overall population trend of the portion of the population with sufficient data (i.e., at least five records). This monitored population represented approximately 19% of the global seabird population. We found the monitored portion of the global seabird population to have declined overall by 69.7% between 1950 and 2010. This declining trend may reflect the global seabird population trend, given the large and apparently representative sample. Furthermore, the largest declines were observed in families containing wide-ranging pelagic species, suggesting that pan-global populations may be more at risk than shorter-ranging coastal populations.”

Grey-headed Albatross family, photograph by Rowan Treblico

Reference:

Paleczny, M., Hammill, E., Karpouzi, V. & Pauly, D. 2015.  Population trend of the World’s monitored seabirds, 1950-2010.  PLoS ONE 10(6): e0129342. doi:10.1371/journal.pone.0129342

John Cooper, ACAP Information Officer, 13 June 2015

In 2014 ACAP made a grant to New Zealand’s National Institute of Water and Atmospheric Research (NIWA) to undertake a population estimate of the White-chinned Petrel Procellaria aequinoctialis on Disappointment Island, Auckland Islands.  The field work was carried out over the 2014/15 summer by University of Otago PhD student Kalinka Rexer-Huber (click here), who has now produced a report of the results of her census.

Disappointment Island, photograph by Barry Baker 

The report’s summary follows:

“White-chinned petrels Procellaria aequinoctialis are one of the seabird species most affected by fisheries bycatch, yet some populations remain virtually unstudied.  The size of the breeding population on the Auckland Islands, New Zealand, is unknown.  We estimated the population size of white-chinned petrels on Disappointment Island, thought to be a key breeding site in the Auckland Islands, taking into account the detection probability of burrows via distance sampling and burrow occupancy.  Eighty line transects were distributed over the island, with a total line length of 1 600 m.  White-chinned petrel burrows occurred at a density of 644 (95% confidence intervals: 487–850) burrows/ha, with an overall burrow detection probability of 0.33 ± 0.03.  We document an estimated total of 153 100 (115 900– 202 200) breeding pairs of white-chinned petrels on Disappointment Island in mid incubation.”

With thanks to Kalinka Rexer-Huber.

White-chinned Petrel burrow on Disappointment Island, photograph by Graham Parker

Setting out a line transect, photograph by Graham Parker

 Whie-chinned Petrel on Disappointment Island, photograph by Graham Parker

Reference:

Rexer-Huber, K., Parker, G.C., Sagar, P. & Thompson, D. 2015.  White-chinned Petrel Population Estimate, Disappointment Island (Auckland Islands).  Report to the Agreement for [sic] the Conservation of Albatrosses and Petrels.  Dunedin: Parker Conservation.  14 pp.

John Cooper, ACAP Information Officer, 12 June 2015

The Sub-Committee on Ecosystems of the International Commission for the Conservation of Atlantic Tunas (ICCAT) is meeting intersessionally this week at the commission’s headquarters in Madrid, Spain (click here).

Among other matters up for discussion at the meeting is the initiation of a review of the efficiency of seabird by-catch methods as set out in ICCAT Recommendation 11.09 “Supplemental Recommendation by ICCAT on Reducing Incidental Bycatch of Seabirds in ICCAT Longline Fisheries”. This recommendation lists line-weighting, use of bird-scaring lines and night setting with minimum deck lighting as mitigation measures.

A deployed bird-scaring line, photograph by Vero Cortes

ACAP is being represented at the meeting by Anton Wolfaardt, Convenor, of its Seabird Bycatch Working Group.

John Cooper, ACAP Information Officer, 11 June 2015