|Scientific Name:||Thalassarche chrysostoma|
|Species Authority:||(Forster, 1785)|
|Red List Category & Criteria:||Vulnerable A4bd ver 3.1|
|Reviewer/s:||Butchart, S. & Taylor, J.|
|Contributor/s:||Arata, J., Cooper, J., Croxall, J., Gales, R., Phillips, R., Robertson, C., Ryan, P. & Xavier, J.|
This species is classified as Vulnerable because it is declining at a rapid rate over three generations (90 years), probably largely owing to incidental mortality on longline fisheries. If the severe declines observed at some sites also occur elsewhere, the species would warrant uplisting to Endangered.
Thalassarche chrysostoma has a circumpolar distribution over cold subantarctic and Antarctic waters (ACAP 2009). It breeds on South Georgia (Georgias del Sur), Islas Diego Ramirez and Ildefonso (Chile), Prince Edward and Marion Islands (South Africa), Crozet Islands, Kerguelen Islands (French Southern Territories), Campbell Island (New Zealand) and Macquarie Island (Australia). The annual breeding population is c.96,000 pairs, equivalent to a total population of c.250,000 mature individuals in this biennially breeding bird (Croxall and Gales 1998, Brooke 2004). Approximately half the global population occurs on South Georgia (ACAP 2009). Its range at sea while breeding lies largely within or south of the Antarctic Polar Frontal Zone (Prince et al. 1998, Phillips et al. 2004). At South Georgia the population has declined by at least 20.9% between 1985 and 2004, and at a possibly even greater rate due to declines of 2.2% in mixed colonies with T. melanophrys. The trend for Bird Island, South Georgia shows an even greater decline of 2.9% decrease per annum between 1991 and 2004 (ACAP 2009). Adult survival on South Georgia decreased from 95% pre-1970 to 93% in 1987, and breeding success also decreased over the same period (from 40% to 39%) (Croxall 2008). At Marion Island the population increased by 2.5% per annum between 1975 and 2007, increasing at a slower rate of 0.6% from 1988, and the trend over 1988-2011 was estimated at a 1.2% increase per year over the period (BirdLife International unpublished data). Annual survival probability for adults at Marion Island was determined to be 0.951 ± 0.006 (SE). At Campbell, the population has declined by 79-87% since the 1940s (Taylor 2000). Trends are unknown for the Chilean islands. The small population at Macquarie Island was stable between 1995 and 2007, and is likely to have been so since the mid-1970s (ACAP 2009). Documented declines to date suggest the population has decreased by 15% since the mid-1980s, and projected future population declines amount to c.49% over three generations (90 years) (BirdLife International unpublished data). This overall decline could prove higher if colonies assumed to have maintained stable populations are also declining. During the non-breeding season South Georgia birds have been recorded making one or more global circumnavigations, the fastest in just 46 days (Croxall et al. 2005). All New Zealand banded birds have been recovered west of New Zealand in Australian zone (G. Taylor in litt. 2008).
Native:Antarctica; Argentina; Australia; Brazil; Chile; Falkland Islands (Malvinas); French Southern Territories (the); Heard Island and McDonald Islands; Namibia; New Zealand; Saint Helena, Ascension and Tristan da Cunha; South Africa; South Georgia and the South Sandwich Islands; Uruguay
Vagrant:Angola (Angola); Panama
Present - origin uncertain:Bouvet Island; Peru
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||There are an estimated c.96,000 pairs breeding per year of this biennial species, based on annual breeding population estimates of 48,000 pairs on South Georgia (Poncet <I>et al</I>. 2006), c.7,295 pairs on Marion Island in 2011 (ACAP 2012, although noting that number of pairs fluctuates between years), 2,000 pairs on Prince Edward Island (Ryan et al. 2009), 7,800 pairs on Campbell Island (Moore 2004), 17,187 pairs in Chile (ACAP 2012), and populations on Macquarie Island, Crozet and Kerguelen as given in Gales (1998) (84, 5,946 and 7,905 pairs respectively). This sums to an estimate of c.96,000 pairs breeding each year, equivalent to at least 250,000 mature individuals (Croxall and Gales 1998, Brooke 2004).|
|Habitat and Ecology:||Behaviour This species is a biennially breeder, although 5.4% and 1% of successful breeders on Marion Island and Bird Island respectively, attempt to breed annually. Birds return to colonies between late September and early October, laying occurs in October and chicks hatch by December. Chicks fledge from April to May, returning to breeding colonies at the earliest at 3 years of age but generally at 6 or 7 years old. First breeding can begin as early as 7 years old, but the average age on Campbell Island is 13.5 years old and the modal age on South Georgia is 12 years old. It feeds by surface-seizing but can also dive up to depths of 6 m (ACAP 2009). Substantial segregation in foraging areas is apparent for male and female Grey-headed Albatross during incubation at South Georgia, with males travelling on average further than females (Phillips et al. 2004). At Iles Kerguelen, Campbell Island and South Georgia (Islas Georgias del Sur), the species is principally an oceanic forager, concentrating in the Antarctic Polar Frontal Zone and associated oceanic upwellings. However, in years of low availability, chick-rearing birds from South Georgia (Islas Georgias del Sur) forage mainly in Antarctic shelf-slope waters around the South Shetland Islands and the Antarctic Peninsula. Prey biogeography also indicates some neritic foraging around Iles Kerguelen and Campbell Island during chick rearing (ACAP 2009). On Marion Island, incubating birds foraged in the Sub-tropical Frontal Zone and the Subantarctic Zone in association with what are most likely eddies. In contrast, during chick rearing, foraging was concentrated in the Subantarctic and Polar Frontal Zones to the south-west of the island, also in association with eddies (Nel et al. 2000, Nel et al. 2001). Habitat Breeding It breeds on steep slopes or cliffs, generally with tussock-grass. Diet Its diet is variable with locality and year (ACAP 2009). It feeds mainly on cephalopods and fish, but crustaceans, carrion and lampreys are locally important (Prince 1980, Cherel et al. 2002, Xavier et al. 2003, Arata et al. 2004). It actively scavenges longline baits.|
|Major Threat(s):||As this species generally forages over oceanic waters it is less likely to encounter longline fisheries targeting Patagonian toothfish in shelf areas, although mortality of breeding birds is still recorded in these fisheries (ACAP 2009). In Australian waters, up to c.400 individuals (>80% juvenile) were killed annually in 1989-1995 by Japanese longliners (Gales et al. 1998). In the Indian Ocean, illegal or unregulated fishing for Patagonian toothfish Dissostichus eleginoides killed an estimated 10,000-20,000 albatrosses (mainly this species) in 1997 and 1998 (CCAMLR 1997, CCAMLR 1998). At Campbell, the long-term decline, which began well before local longline fishery development, appears to be caused by environmental factors, possibly rising sea-surface temperatures resulting in food shortages, but longline fisheries beyond the New Zealand Exclusive Economic Zone (EEZ) may also contribute (Waugh et al. 1999). The species is not caught on fishing vessels monitored by New Zealand observers within the EEZ (G. Taylor in litt. 2008). Outside of EEZs, due to its circumpolar distribution, T. chrysostoma is potentially vulnerable to Southern Ocean pelagic fisheries worldwide. The extensive use of the Subtropical Convergence and Sub-Antarctic Zones by incubating birds from Marion Island, especially females, bring them into contact with intense southern bluefin tuna Thunnus maccoyii longline fishing activity in international waters (40-45°) (ACAP 2009).|
Conservation Actions Underway
CMS Appendix II and ACAP Annex 1. Population monitoring and foraging studies are being undertaken at South Georgia, Diego Ramirez, Marion, Macquarie and Campbell Islands. Macquarie and Campbell are World Heritage Sites and the Prince Edward Islands are a Special Nature Reserve. Conservation Actions Proposed
Continue existing monitoring and commence at poorly-known sites (Environment Australia 1999). Determine migration patterns in off seasons from other populations and overlap with fisheries, particularly those operating in the southern Indian Ocean. Promote adoption of best-practice mitigation measures in all fisheries within the species's range, particularly via intergovernmental mechanisms such as ACAP, CCAMLR and FAO.
|Citation:||BirdLife International 2012. Thalassarche chrysostoma. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 18 May 2013.|
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