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

A Northern Giant Petrel Macronectes halli (named “Gazza” and likely to be a juvenile by its all-brown plumage) under rehabilitation by the NGO Australian Seabird Rescue in Ballina, New South Wales was recently found to have regurgitated parts of a balloon over a period of several days in its cage.  Along with the balloon fragments the bird also regurgitated a piece of hard plastic and fishing line. The bird was collected from a beach “suffering from exhaustion” late last month.  Following an X-ray, "Gazza" has now been pronounced balloon-free.

“Gazza” and the regurgitated balloon fragments, photographs courtesy of Australian Seabird Rescue

Ingestion of latex balloons is a well-known conservation issue for marine turtles, which apparently mistake ruptured balloons at sea for jellyfish, their natural food, leading to blocked guts and death by starvation (click here).

However, ingestion of balloons by procellariiform seabirds is less well known.  Remains of latex balloons were found in 1-2% of the stomachs of Arctic or Northern Fulmars Fulmarus glacialis beached in the North Sea in a study published in 2008 by Jan van Franeker, and as reported by him to ACAP Latest News. (click here).  Dvaid Ainley and colleagues have reported what they thought to be rubber from a meteoreological balloon in an Antarctic Petrel Thalassoica antarctica.

In 2006, Australian Seabird Rescue successfully removed a balloon and its attached ribbon that had been swallowed by a Southern Giant Petrel M. giganteus under care (click here).

The orange balloon and ribbon removed from a Southern Giant Petrel in 2006, photograph courtesy of Australian Seabird Rescue

Balloons have been reported ingested by or entangled with Black-browed Albatross Thalassarche melanophris and Black-footed Phoebastria nigripes Albatrosses.  The latter species has also been photographed investigating a floating balloon at sea.  Click here for an earlier story on “balloon pollution” in ACAP Latest News.

Black-footed Albatross entangled with a balloon

A balloon ribbon tape attached to a balloon was found inside the gut of a juvenile Black-browed Albatross

Black-footed Albatross encounters a floating balloon

Click here to read more about the conservation issues of releasing lighter-than-air balloons.

With thanks to Peter Ryan and Jan van Franeker for information.

References:

Ainley, D.G., Fraser, W.R. & Spear, L.B. 1990. The incidence of plastic in the diets of Antarctic seabirds, in: Shomura, R.S. & Godfrey, M.L. 1990.  Proceedings of the Second International Conference on Marine Debris 2-7 April 1989, Honolulu, Hawaii, Vol. 1. NOAA Technical Memorandum, NMFS-SWFSC(154). pp. 682-691.

van Franeker J.A. 2008.  Ballonnen in zee.  Sula 21(1): 44-46.

John Cooper, ACAP Information Officer, 10 June 2015, updated 11 June 2015