Procellaria aequinoctialis

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	AVES	PROCELLARIIFORMES	PROCELLARIIDAE

Scientific Name:

Procellaria aequinoctialis

Species Authority:

Linnaeus, 1758

Common Name/s:

English	–	White-chinned Petrel
Spanish	–	Pardela Gorgiblanca

Assessment Information [top]

Red List Category & Criteria:

Vulnerable A4bcde ver 3.1

Year Published:

2010

Assessor/s:

BirdLife International

Reviewer/s:

Calvert, R., Butchart, S., Bird, J.

Contributor/s:

Robertson, C., Martin, T., Phillips, R., Cooper, J., Croxall, J., Barbraud, C., Taylor, G.

Justification:
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 are suspected in recent years; the probability that these circumstances will continue and its susceptibility to predation and loss of breeding habitat indicate a rapid and substantial population decrease is likely.

History:

2008	–	Vulnerable
2005	–	Vulnerable
2004	–	Vulnerable
2000	–	Vulnerable
1994	–	Not Recognized
1988	–	Not Recognized

Geographic Range [top]

Range Description:	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. 3.5 million individuals. This is based on estimates of 900,000 breeding pairs on South Georgia³⁶, 23,600 breeding pairs (9,800 to 36,800) on Crozet³¹, 186,000-297,000 pairs on the Kerguelen Islands³⁵ and at least c.100,000 on Disappointment (Auckland) and the Antipodes¹¹. At least 55 pairs breed on the Falkland Islands¹⁷. On Bird Island (South Georgia), the population has apparently decreased by 28% over 20 years³, while in Prydz Bay (Antarctica), the number of birds at sea decreased by 86% during 1981-1993¹⁴. White-chinned Petrels forage north to the subtropics and south to the pack-ice edge off Antarctica^3,19,28, and are distributed widely in all southern oceans⁷.
Countries:	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; South Africa; South Georgia and the South Sandwich Islands; United States; United States; United States; United States; United States; United States; United States; United States; United States; Uruguay Present - origin uncertain: Bouvet Island; Ecuador
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	This species has an estimated global population of c.3.5 million individuals, based on the estimated number of breeding pairs extrapolated according to a ratio from Brooke (2004).
Population Trend:	Decreasing

Habitat and Ecology [top]

Habitat and Ecology:	Behaviour It is a burrow-nesting annual breeder, laying in mid-October to mid-November³⁷. Chicks usually fledge in late April³⁵. Outside the chick rearing period, White-chinned Petrels breeding on South Georgia travel to Patagonian Shelf waters to feed¹⁹. 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 Namibia³². Individuals from the Kerguelen Islands also winter off the coasts of South Africa and Namibia over the Benguela Current³⁵. Diet White-chinned Petrels feed on cephalopods, crustaceans and fish^2,28 and fisheries processing waste or discarded longline baits. Foraging range Birds avoid competition with other seabirds by ranging more widely when searching out food resources, travelling up to 8,000 km on feeding forays in the breeding season^15,19,28. Individuals breeding at the Crozet 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 south²⁸.
Systems:	Terrestrial; Marine

Habitat and Ecology:

Behaviour It is a burrow-nesting annual breeder, laying in mid-October to mid-November³⁷. Chicks usually fledge in late April³⁵. Outside the chick rearing period, White-chinned Petrels breeding on South Georgia travel to Patagonian Shelf waters to feed¹⁹. 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 Namibia³². Individuals from the Kerguelen Islands also winter off the coasts of South Africa and Namibia over the Benguela Current³⁵. Diet White-chinned Petrels feed on cephalopods, crustaceans and fish^2,28 and fisheries processing waste or discarded longline baits. Foraging range Birds avoid competition with other seabirds by ranging more widely when searching out food resources, travelling up to 8,000 km on feeding forays in the breeding season^15,19,28. Individuals breeding at the Crozet 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 south²⁸.

Systems:

Terrestrial; Marine

Threats [top]

Major Threat(s):	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 winter¹⁰ and constitutes virtually all the recorded seabird bycatch from the Namibian hake fishery^1,22. In South Africa, White-chinned Petrels constitute 10% and 55% of the bycatch in pelagic and demersal longline fisheries²². 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 Petrels²¹. In the Indian Ocean, between 2001 and 2003 the legal longline fishery for Patagonian toothfish Dissostichus eleginoides killed 12,400 P. aequinoctialis per year³³. Following the introduction of mitigation measures this figure dropped to approximately 2,500 birds in the 2005-2006 season²⁰. 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^4,5. In recent years (2006) this figure has reduced to 4,583 seabirds in total²⁰. In the Australian Fishing Zone, more than 800 are potentially killed annually⁸ 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. aequinoctialis²³. 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 less 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 winter. This may mean 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 decline³⁵. Rats (Rattus rattus and R. norvegicus) are significant predators at some breeding sites, such as Crozet³⁴, and cats predate nests at Kerguelen³². At South Georgia, breeding habitat is extensively degraded due to erosion by expanding populations of Antarctic fur seal Arctocephalus gazella³. Introduced reindeer also degrade breeding habitat on South Georgia ¹⁸.

Major Threat(s):

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 winter¹⁰ and constitutes virtually all the recorded seabird bycatch from the Namibian hake fishery^1,22. In South Africa, White-chinned Petrels constitute 10% and 55% of the bycatch in pelagic and demersal longline fisheries²². 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 Petrels²¹. In the Indian Ocean, between 2001 and 2003 the legal longline fishery for Patagonian toothfish Dissostichus eleginoides killed 12,400 P. aequinoctialis per year³³. Following the introduction of mitigation measures this figure dropped to approximately 2,500 birds in the 2005-2006 season²⁰. 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^4,5. In recent years (2006) this figure has reduced to 4,583 seabirds in total²⁰. In the Australian Fishing Zone, more than 800 are potentially killed annually⁸ 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. aequinoctialis²³. 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 less 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 winter. This may mean 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 decline³⁵. Rats (Rattus rattus and R. norvegicus) are significant predators at some breeding sites, such as Crozet³⁴, and cats predate nests at Kerguelen³². At South Georgia, breeding habitat is extensively degraded due to erosion by expanding populations of Antarctic fur seal Arctocephalus gazella³. Introduced reindeer also degrade breeding habitat on South Georgia ¹⁸.

Conservation Actions [top]

Conservation Actions:	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 Kerguelen¹⁸. Several breeding sites are in protected areas. Conservation Actions Proposed Continue and extend monitoring studies. Where feasible, eliminate alien predators 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. Develop and implement plans to remove reindeer from South Georgia.

Conservation Actions:

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 Kerguelen¹⁸. Several breeding sites are in protected areas.

Conservation Actions Proposed
Continue and extend monitoring studies. Where feasible, eliminate alien predators 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. Develop and implement plans to remove reindeer from South Georgia.

Citation:	BirdLife International 2010. Procellaria aequinoctialis. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 24 May 2012.
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