|Scientific Name:||Procellaria aequinoctialis|
|Species Authority:||Linnaeus, 1758|
|Taxonomic Notes:||Procellaria aequinoctialis (Sibley and Monroe 1990, 1993) has been split into P. aequinoctialis and P. conspicillata following Brooke (2004).|
|Red List Category & Criteria:||Vulnerable A4bcde ver 3.1|
|Reviewer/s:||Butchart, S. & Symes, A.|
|Contributor/s:||Barbraud, C., Bugoni, L., Colabuono, F., Cooper, J., Croxall, J., Martin, T., Phillips, R., Robertson, C. & Taylor, G.|
This species is classified as Vulnerable because of suspected rapid declines, although almost no reliable estimates of historical populations exist. Very high rates of incidental mortality in longline fisheries have been recorded in recent years; the probability that these circumstances will continue and its susceptibility to predation and the degradation of breeding habitat indicate that a rapid and on-going population decline is likely.
Procellaria aequinoctialis breeds on South Georgia (Georgias del Sur), Prince Edward Islands (South Africa), Crozet Islands, Kerguelen Islands (French Southern Territories), Auckland, Campbell and Antipodes Islands (New Zealand), and in small numbers in the Falkland Islands (Islas Malvinas). Recently revised population estimates give a global population of c.3 million individuals. This is based on estimates of 773,150 breeding pairs on South Georgia in 2007 (ACAP 2012), 23,600 breeding pairs (9,800 to 36,800) on Crozet (Barbraud et al. in litt. 2008), 186,000-297,000 pairs on the Kerguelen Islands (Barbraud et al. 2009), at least c.100,000 on Disappointment (Auckland) in 1988 (ACAP 2012), 10,000 on Campbell in 1985 (ACAP 2012) and 58,725 on the Antipodes in 2011 (ACAP 2012). At least 55 pairs breed on the Falkland Islands, on Kidney Island, New Island and Bottom Island (Reid et al. 2007). On Bird Island (South Georgia), the population has apparently decreased by 28% over 20 years (Berrow et al. 2000), while in Prydz Bay (Antarctica), the number of birds at sea decreased by 86% during 1981-1993 (Woehler 1996). The species forages north to the subtropics and south to the pack-ice edge off Antarctica (Berrow et al. 2000, Catard et al. 2000, Phillips et al. 2006), and is distributed widely in all southern oceans (Croxall et al. 1984).
Native:Antarctica; Argentina; Australia; Brazil; Chile; Falkland Islands (Malvinas); French Southern Territories (the); Heard Island and McDonald Islands; Madagascar; Mozambique; Namibia; New Zealand; Peru; Saint Helena, Ascension and Tristan da Cunha; South Africa; South Georgia and the South Sandwich Islands; Uruguay
Present - origin uncertain:Bouvet Island; Ecuador
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||A global population of 1,200,000 breeding pairs, down from 1,430,000 pairs in the 1980s, is estimated based on figures from 1985-2011. This equates to an estimated global population of c.3 million mature individuals, based on the estimated number of breeding pairs extrapolated according to a ratio from Brooke (2004).|
|Habitat and Ecology:||Behaviour It is a burrow-nesting annual breeder, laying in mid-October to mid-November (ACAP 2009). Chicks usually fledge in late April (Barbraud et al. 2009). Outside the chick-rearing period, White-chinned Petrels breeding on South Georgia travel to Patagonian Shelf waters to feed (Phillips et al. 2006). Satellite tracking and ring recoveries from birds on Crozet Islands show that they spend the non-breeding season off the coasts of South Africa and Namibia (Barbraud in litt. 2008). Individuals from the Kerguelen Islands also winter off the coasts of South Africa and Namibia over the Benguela Current (Péron et al. 2010a). Diet White-chinned Petrels feed on cephalopods, crustaceans and fish (Berrow et al. 1999, Catard et al. 2000, Delord et al. 2010) and fisheries processing waste or discarded longline baits. Cephalopods were found to comprise the greatest component of the diet in one study (91% occurrence, 92% number, 90% mass) (Colabuono and Vooren 2007). Foraging range Birds range widely when searching for food resources, travelling up to 8,000 km on feeding forays in the breeding season (Berrow et al. 2000, Catard et al. 2000, Phillips et al. 2006, Delord et al. 2010a). Individuals breeding at the Crozet and Kerguelen islands display a bimodal foraging strategy, conducting either short trips to the surrounding shelf or long trips ranging from subtropical waters in the north to Antarctic waters in the south (Catard et al. 2000). Individuals breeding at the Kerguelen Islands target the seasonal ice zone where melting sea ice is gradually broken into floes and forage almost exclusively in open water (Péron et al. 2010b).|
P. aequinoctialis constitute the majority of bird bycatch in Southern Ocean longline fisheries. It is one of the commonest species attending longline vessels off south-east Brazil during winter (Olmos 1997, Bugoni et al. 2008) and off Uruguay (Jiménez et al. 2009), and constitutes virtually all the recorded seabird bycatch from the Namibian hake fishery (Barnes et al. 1997, Petersen et al. 2007). In South Africa, White-chinned Petrels constitute 10% and 55% of the bycatch in pelagic and demersal longline fisheries respectively (Petersen et al. 2007). Prior to the introduction of bird streamer lines as a vessel permit condition in August 2006, approximately, 10% of the 18,000 birds killed annually in the South African hake trawl fishery were White-chinned Petrels (Watkins et al. 2007). In the Indian Ocean, between 2001 and 2003 the legal longline fishery for Patagonian toothfish Dissostichus eleginoides killed c.12,400 P. aequinoctialis per year (Delord et al. 2005). Following the introduction of mitigation measures this figure dropped to approximately 2,500 birds in the 2005-2006 season (CCAMLR 2006), and to 740 birds in the 2008-2009 season (CCAMLR 2010). In addition, an estimated 31,000-111,000 and 50,000-89,000 seabirds in 1997 and 1998 respectively, c.60% of which were P. aequinoctialis, were thought to be killed by IUU vessels (CCAMLR 1997, 1998). In recent years (2006) this figure has fallen to 4,583 seabirds in total (CCAMLR 2006). It is the second most common species caught in the Argentinean longline fleet, with an average capture rate for the period 1999-2003 of 0.014 ± 0.09 individuals per 1,000 hooks (Laich and Favero 2007). During autumn-winter most captures took place in the north of the Patagonian Shelf, whereas in spring-summer most were to the south, between 45-50 degrees South (Laich and Favero 2007). In the Australian Fishing Zone, more than 800 are potentially killed annually (Gales et al. 1998) and, in New Zealand between 2003 and 2005, 14.5% of all the seabirds caught in trawl and longline fisheries and returned for autopsy were P. aequinoctialis (Baird and Smith 2007). Barbraud et al. (2009) estimated that any additional source of mortality that approaches 31,000 individuals would result in a population decline at the Kerguelen Islands. Although only 30% of this number are killed in local waters, and even fewer are now killed due to the implementation of mitigation measures, more than 31,900 White-chinned Petrels are estimated to be killed each year by demersal longline fishing in the Benguela Current marine ecosystem where individuals from the Kerguelen Islands spend the winter. This may mean that the population at the Kerguelen Islands is decreasing, although the additional presence of non-breeders from the Crozet Islands at the Benguela Current means that further research is required to confirm the population decline (Barbraud et al. 2009). Dillingham & Fletcher (2011) estimated that the potential for the world population to sustain additional mortality was 15,000 individuals. Rats (Rattus rattus and R. norvegicus) are significant predators at some breeding sites, such as Crozet (Jones et al. 2008), and cats predate nests at Kerguelen (Barbraud in litt. 2008). At South Georgia, breeding habitat is extensively degraded owing to erosion by expanding populations of Antarctic fur seal Arctocephalus gazella (Berrow et al. 2000). Introduced reindeer Rangifer tarandus also degrade breeding habitat on South Georgia (Poncet 2007). Although no adverse effects have been proven until recently, there are now reports of relatively high frequencies of plastic ingestion (Ryan 2008, Colabuono et al. 2009), as well as the occurrence of persistent organic pollutants (Colabuono et al. 2012) in this species.
Conservation Actions Underway
CMS Appendix II ACAP Annex 1. Population monitoring and foraging ecology studies are being undertaken at South Georgia, Crozet, Prince Edward and Kerguelen (Poncet 2007). Several breeding sites are in protected areas. Conservation Actions Proposed
Continue and extend monitoring studies. Where feasible, eliminate alien predators and reindeer from breeding islands. Promote adoption of best-practice mitigation measures in all fisheries within the species's range, including via intergovernmental mechanisms such as ACAP, FAO, and Regional Fisheries Management Organisations such as CCAMLR. Implement plans to remove rats and reindeer from South Georgia (R. Phillips in litt. 2012). Develop and implement plans to remove pigs from Auckland Island, rats, cats and reindeer from Kerguelen, and rats from Ile de la Possession, Crozet (R. Phillips in litt. 2012).
|Citation:||BirdLife International 2012. Procellaria aequinoctialis. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 20 May 2013.|
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