|Scientific Name:||Phoebetria fusca|
|Species Authority:||(Hilsenberg, 1822)|
|Red List Category & Criteria:||Endangered A4bd ver 3.1|
|Reviewer/s:||Butchart, S. & Taylor, J.|
|Contributor/s:||Cooper, J., Crawford, R., Croxall, J., Cuthbert, R., Hilton, G., Misiak, W., Ryan, P. & Weimerskirsch, H.|
This species qualifies as Endangered owing to a very rapid decline over three generations (90 years), probably due to interactions with fisheries. Since 1980, three sites (Crozet, Marion and Gough) have witnessed severe declines, although the population at Prince Edward may have increased between 2002-2009. However, high variability in population counts between years necessitates caution and further data are required before a change in status should be considered.
Phoebetria fusca breeds on islands in the South Atlantic and Indian Oceans. The total annual breeding population is estimated at 13,200 - 14,500 pairs (Ryan et al. 2003), consisting of c.5,000 pairs on Gough Island (Cuthbert and Sommer 2004a), 3,157 pairs in the Tristan da Cunha group (to UK) (ACAP 2012), c. 1,450 pairs on Prince Edward and c. 1,700 pairs on Marion Island (South Africa) (ACAP 2012), 2,080-2,200 pairs on the Crozet Islands (Delord et al. 2008), and 470 pairs on Amsterdam Island (French Southern Territories) (Delord et al. 2008). The pelagic distribution is mainly between 30°S and 60°S in the southern Indian and Atlantic Oceans, with a southern limit of c. 65°S near Antarctica and a northern limit of c. 20°S. Adults move north in winter from sub-Antarctic to subtropical seas, whereas immature birds tend to remain in subtropical seas year round. The species infrequently disperses eastward to the Tasman Sea and New Zealand waters (ACAP 2009). On Possession Island (Crozet), the population declined by 58% between 1980 and 1995 (Weimerskirch and Jouventin 1998) and continues to decline, although at a slower rate. This equates to an 82% decline between 1980 and 2006 (Delord et al. 2008). On Marion Island, the population declined by 25% from 1990-19988. On Gough Island (c.36% global population), the population appears to have decreased by over 50% from 1972-2000 ( Cuthbert and Sommer 2004a), although recent counts of breeding birds on Gough in 2000, 2003 and 2005 indicate no change in breeding numbers. Limited counts have been made on Tristan and Inaccessible, and indicate a population of c.3,157 (ACAP 2012). Overall, these declines equate to 60% over three generations (90 years), with a trend start date of 1960.
Native:Argentina; Australia; Brazil; French Southern Territories (the); Heard Island and McDonald Islands; Saint Helena, Ascension and Tristan da Cunha; South Africa; Uruguay
Vagrant:Antarctica; Falkland Islands (Malvinas); Mauritius; New Zealand; Réunion; South Georgia and the South Sandwich Islands
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The total annual breeding population is estimated at c.14,000 pairs, consisting of c.5,000 pairs on Gough Island (Cuthbert and Sommer 2004a), 3,157 pairs in the Tristan da Cunha group (ACAP 2012), c.1,450 pairs on Prince Edward and 1,701 pairs on Marion Islands (Ryan et al. 2009, ACAP 2012), 2,174 pairs on the Crozet Islands (Delord 2008), fewer than five pairs on Kerguelen Island, and 300-400 pairs on Amsterdam Island (Carboneras 1992b).|
|Habitat and Ecology:||Behaviour It breeds in loose colonies of up to 50-60 nests (Marchant and Higgins 1990). The breeding season extends through summer, eggs are laid in October and November, hatch in early to mid-December and chicks fledge in May (ACAP 2009). Successful pairs seldom breed in the following summer (Ryan 2007). A single egg is laid, with no replacement laying. Adults make a combination of long commuting flights early in the incubation period, looping searching flights later in incubation and linear searching during chick brooding (ACAP 2009). Habitat Breeding It breeds on cliffs or steep slopes where it can land and take off right next to the nest (Marchant and Higgins 1990). Diet Squid, fish, crustaceans and carrion all feature prominently in the diet, although proportions of each vary between years and locations (ACAP 2009).|
|Major Threat(s):||Both adults and juveniles have been caught as bycatch by Japanese longline vessels fishing inside and beyond the Australian Fishing Zone (Gales et al. 1998) and at least some are killed on tuna longlines off southern Africa (Ryan et al. 2003). However, only one bird (of 1,500 examined) is known to have been killed by vessels with observers in the Prince Edward fishery (P. G. Ryan in litt. 1999). One banded bird has been caught by a Chinese Taipei longline vessel fishing in the Indian Ocean (Delord et al. 2008). The population on Possession Island, Crozet Islands has nevertheless been found to be significantly and negatively affected by fisheries bycatch, particularly adult survival rates (in the absence of fishing effort, predicted adult survival was 0.902 as opposed to 0.884) (Rolland et al. 2010). Adult survival was found to be low and more variable than in similar species, which is very likely the cause of their decline (Rolland et al. 2010). Introduced rats and cats on the Kerguelen Islands are not known to affect the species, but cats and rats on Amsterdam Island are known to impact the species sufficiently to cause population-level changes (ACAP 2009). The harvest of chicks and adults in the Tristan group is banned and illegal poaching is now probably very rare (P. G. Ryan in litt. 1999). The species could be affected by avian cholera and erysipelas bacteria on Amsterdam Island (H. Weimerskirch 2004).|
Conservation Actions Underway
CMS Appendix II and ACAP Annex 1. Population monitoring and foraging studies are being undertaken at Possession, Amsterdam and Marion. The species is protected in Tristan da Cunha (J. Cooper in litt. 1999, P. G. Ryan in litt. 1999). Gough is a World Heritage Site and the Prince Edward Islands are a Special Nature Reserve. Inaccessible and Gough Islands are nature reserves. A population estimate was made at Gough during 2000-2001, and a repeatable monitoring protocol was devised (Cuthbert and Sommer 2004b). Monitoring has been repeated in 2003 and 2006 at Gough. Gough and Tristan birds have also been remotely-tracked to determine at-sea distribution. A project on Tristan da Cunha (2004-2006) is undertaking population counts. In 2007, Crozet, Amsterdam and Kerguelen Islands were declared Nature Reserves. Conservation Actions Proposed
Repeat standardised population surveys at all key sites, most notably Gough and Tristan da Cunha. Determine foraging distribution of the species and its overlap with longline fisheries. Promote adoption of best-practice mitigation measures in all fisheries within the species's range, particularly via intergovernmental mechanisms such as ACAP, CCAMLR, FAO, and Regional Fisheries Management Organisations such as the tuna commissions in the Atlantic and Indian Oceans (ICCAT, IOTC).
|Citation:||BirdLife International 2012. Phoebetria fusca. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 24 May 2013.|
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