The licensed longline fishery for Patagonian Toothfish Dissostichus eleginoides in the French Exclusive Economic Zone (EEZ) around the sub-Antarctic Kerguelen Islands has reported to the Working Group on Fish Stock Assessment (WG-FSA) of the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) that 18 seabird mortalities were observed in the 2012/13 fishing season, consisting of 16 White-chinned Petrels Procellaria aequinoctialis and two Northern Giant Petrels Macronectes halli.  An estimated extrapolated mortality of 70 birds was calculated.

From 2007 to 2013 a total of 690 birds of three species (all ACAP-listed and including the Grey Petrel P. cinerea) were reported killed over the seven-year period, with a decline from a high of 257 in 2008.  White-chinned Petrels were the most commonly killed, at 608 over seven years.

Grey Petrel at sea, photograph by Peter Ryan

Conservation Measure 25-02 ‘Minimisation of the incidental mortality of seabirds in the course of longline fishing or longline fishing research in the CAMLR Convention Area’ was adhered to in the fishery.  An exemption was allowed to the requirement for night setting by achieving the sink rates described in CM 25-02 and subject to a seabird by-catch limit.

The report states that “[a]dditional measures for the upcoming season will also be applied … , including:

(i) changes to the bird exclusion device to ensure it is effective in all weather conditions

(ii) closure of fishing areas and quota allocation reduction to vessels that have high by-catch rates

(iii) education and training will be strengthened by regular meetings between TAAF and fishing masters of vessels with high by-catch

(iv) data will continue to be collected and submitted using CCAMLR standard methods and forms

(v) a demographic study on the white-chinned petrel will be undertaken at Kerguelen Island, as well as the continued population counts of white-chinned petrels on the Kerguelen archipelago.”

Reference:

CCAMLR  2013.  Fishery Report 2013: Dissostichus eleginoides Kerguelen Islands French EEZ (Division 58.5.1).  Hobart: Commission for the Conservation of Antarctic Marine Living Resources.  9 pp.

John Cooper, ACAP Information Officer, 09 August 2014

A recently posted account to the Southern Seabirds Solutions Trust gives details of an expedition to New Zealand’s sub-Antarctic Snares Islands to count breeding Buller’s Albatrosses Thalassarche bulleri (click here).

“The census is undertaken by using maps of previous surveys and counting off each nest with an egg in it (or sitting bird).  In the forest this is hard work but relatively easy compared to the cliffs which comprise nearly the entire coastline; here binoculars are used and counts all written down and cross referenced statistically later.”

A Buller's Albatross at The Snares, photograph by Paul Sagar 

“The 2014 census resulted in around 8,000 pairs of Southern Buller’s being counted - remarkably similar to the 2002 count and around double the number reported breeding in 1969.”  This is the first complete census of the species at The Snares since 2002.

Four birds banded on The Snares in 1972 were resighted, 42 years ago, on the trip.  Click here to read of other old albatrosses at The Snares – and elsewhere in New Zealand.

John Cooper, ACAP Information Officer, 08 August 2014

Lise Ruffino (Section of Ecology, Department of Biology, University of Turku, Turku, Finland) and colleagues have published in the journal Pest Management Science on a rat and plant eradication programme on a French Mediterranean island that supports a small colony of 8-15 pairs of Vulnerable Yelkouan Shearwaters Puffinus yelkouan – a candidate species for listing within ACAP.  A few pairs of Scopoli’s Shearwaters Calonectris diomedea have bred on the island in the past.

The paper’s abstract follows:

“Black rats, Rattus rattus, and mat-forming iceplants, Carpobrotus aff. acinaciformi and Carpobrotus edulis, are pervasive pests on Mediterranean islands.  Their cumulative impacts on native biotas alter the functioning of island ecosystems and threaten biodiversity.  A report is given here of the first attempt to eradicate both taxa from a protected nature reserve in south-eastern France (Bagaud Island).  In order to minimise unwanted hazardous outcomes and produce scientific knowledge, the operations were embedded in a four-step strategy including initial site assessment, planning, restoration and monitoring.

Trapping, which resulted in the removal of 1923 rats in 21 045 trap-nights, made it possible to eliminate a substantial proportion of the resident rat population and to reduce the amount of rodenticide delivered in the second stage of the operation.  Forty tons of Carpobrotus spp. were manually uprooted from a total area of 18 000 m²; yet careful monitoring over a decade is still required to prevent germinations from the seed bank.

Two years after the beginning of the interventions, both eradication operations are still ongoing.  Biosecurity measures have been implemented to reduce reinvasion risks of both taxa.  With the long-term monitoring of various native plants and animals, Bagaud Island will become a reference study site for scientific purposes.”

Yelkouan Shearwater, photograph by Borg Cardona 

With thanks to Karen Bourgeois for information.

Reference:

Ruffino, L., Krebs, E., Passetti, A., Aboucaya, A., Affre, L., Fourcy, D., Lorvelec, O., Barcelo, A., Berville, L., Bigeard, N., Brousset, L., De Méringo, H., Gillette, P., Le Quilliec, P., Limouzin, Y., Médail, F., Meunier, J.-Y., Pascal, M., Pascal, M., Ponel, P., Rifflet, F., Santelli, C., Buisson, E. & Vidal, E. 2014.  Eradications as scientific experiments: progress in simultaneous eradications of two major invasive taxa from a Mediterranean island.  Pest Management Science DOI: 10.1002/ps.3786.

John Cooper, ACAP Information Officer, 07 August 2014

Peggy Ostrom (Department of Zoology, Michigan State University, East Lansing, Michigan, USA) and colleagues have published in the journal Oecologia on variations in hydrogen isotope values in North Pacific albatrosses and petrels.

The paper’s abstract follows:

“Hydrogen isotopes have significantly enhanced our understanding of the biogeography of migratory animals.  The basis for this methodology lies in predictable, continental patterns of precipitation δD values that are often reflected in an organism’s tissues.  δD variation is not expected for oceanic pelagic organisms whose dietary hydrogen (water and organic hydrogen in prey) is transferred up the food web from an isotopically homogeneous water source.  We report a 142 ‰ range in the δD values of flight feathers from the Hawaiian petrel (Pterodroma sandwichensis), an oceanic pelagic North Pacific species, and inquire about the source of that variation.  We show δD variation between and within four other oceanic pelagic species: Newell’s shearwater (Puffinus auricularis newellii), Black-footed albatross (Phoebastria nigripes), Laysan albatross (Phoebastria immutabilis) and Buller’s shearwater (Puffinus bulleri).  The similarity between muscle δD values of hatch-year Hawaiian petrels and their prey suggests that trophic fractionation does not influence δD values of muscle.  We hypothesize that isotopic discrimination is associated with water loss during salt excretion through salt glands.  Salt load differs between seabirds that consume isosmotic squid and crustaceans and those that feed on hyposmotic teleost fish.  In support of the salt gland hypothesis, we show an inverse relationship betweenδD and percent teleost fish in diet for three seabird species.  Our results demonstrate the utility of δD in the study of oceanic consumers, while also contributing to a better understanding of δD systematics, the basis for one of the most commonly utilized isotope tools in avian ecology.”

Reference:

Ostrom, P.H., Wiley, A.E.,Rossman, S., Stricker, C.A. & James, H.F. 2014.  Unexpected hydrogen isotope variation in oceanic pelagic seabirds.  Oecologia 175: 1227-1235.

John Cooper, ACAP Information Officer, 06 August 2014