Justification of Red List Category
An analysis of recent data suggests that this species' population is not undergoing rapid declines, as once thought, and is either stable or increasing. However, modelling of the likely effects of mortality caused by longline fishing fleets, combined with potential losses to breeding colonies from sea-level rise and storm surges, suggests it is appropriate to precautionarily predict a moderately rapid population decline over the next three generations (66 years), hence it is classified as Near Threatened.
Between 1995 and 2017, the average number of breeding pairs per season was c.69,900, which equates to 139,800 mature individuals (ACAP 2017).
Monitoring data from three colonies in Hawaii, representing over 75% of the world's population, suggest that numbers may have decreased by 9.6% between 1992 and 2001 (Gilman and Freifeld 2003, USFWS data per E. Flint 2003). However, linear regression analysis of log-transformed counts at the same colonies suggests that the species’s population has remained stable since at least 1957 and has increased overall since 1923, and matrix modelling has suggested that the population is currently stable or increasing slightly (Arata et al. 2009). In addition, trends over a three generation period (66 years) commencing in 1956 were estimated at +26% using TRIM (ACAP unpubl. data).
In 2003, estimated rates of incidental mortality in longline fisheries in the North Pacific Ocean (based on a moderate bycatch scenario of 8,000 birds being killed per year) resulted in a projected future decline of more than 60% over the next three generations (66 years), if bycatch mortality was not reduced (Lewison and Crowder 2003). However, the demographic parameters for Lewison and Crowder’s (2003) model, namely survival probability, growth probability and fecundity, were based on data from the 1960s and 1970s, for which it was incorrectly assumed that no bycatch took place (Arata et al. 2009). This implies that the basic parameters for a stable population with no additional mortality were actually estimated from a population already experiencing significant bycatch, and were thus underestimated. This appears to have led to an overestimation of the declines that would result from the annual bycatch scenarios tested by Lewison and Crowder (2003), by counting this source of mortality both within the demographic parameter estimates and within the simulation scenario (Arata et al. 2009). Nevertheless, likely bycatch levels are still predicted to cause a decline in the population, albeit not as rapid as previously projected (Arata et al. 2009). Other studies on this species have confirmed the impact of fisheries bycatch on survival (Verán et al. 2007) and the annual population growth rate (Niel and Lebreton 2005). Annual bycatch was estimated at 5,228 birds in 2005, which, if doubled to account for underestimation, approaches the maximum Potential Biological Removal (PBR) level of 11,980 birds, which is calculated to be the maximum level of off-take possible without causing a decline (Arata et al. 2009). The maximum PBR level for this species has also been estimated at 8,850 birds per year (Niel and Lebreton 2005) and 10,000 birds per year (Cousins and Cooper 2000).
It still remains necessary to robustly model the future impact of bycatch on this species. In the meantime, given the risk of bycatch approaching PBR, and potential risk to nesting habitat from sea-level rise modelled for Midway Atoll, site of the world’s largest colony (Storlazzi et al. 2013, Reynolds et al. 2015), it seems appropriate to precautionarily project future declines approaching 60% over the next 66 years (three generations).
Phoebastria nigripes breeds on the Northwestern Hawaiian Islands (U.S.A.), the U.S. Minor Outlying Islands and four outlying islands off Japan. In the past, individual pairs have also bred in Mexico on Guadalupe and San Benedicto islands; however the species has not bred on either island for at least 20 years (ACAP 2010). Colonies have been lost from other Pacific islands (Whittow 1993, Cousins 1998). In total there are estimated to be 70,069 pairs breeding each year (Flint 2007, Naughton et al. 2007, ACAP 2017) in at least 16 locations. The largest population counts have been 28,610 pairs at Midway Atoll for hatch year 2015 and 24, 565 pairs at Laysan Island for hatch year 2012. Together these two sites represent approximately 72% of the global population as estimated by the highest count for each of 16 sites (12 sites surveyed within the last 10 years) (Flint 2007, Naughton et al. 2007, ACAP 2017). On Torishima, 914 chicks were reared from 1,219 pairs in 1998, compared with just 20 in 1964 (Cousins and Cooper 2000). In 2013, 2,060 pairs nested on Torishima (ACAP 2017). The species disperses widely over the northern Pacific Ocean, particularly to the north-east, towards the coastal waters of North America. There have been occasional records in the southern hemisphere (Carboneras 1992, Fernandez et al. 2001, Hyrenbach and Dotson 2001, BirdLife International 2004, Hyrenbach et al. 2006).
The species breeds on beaches and slopes with little or no vegetation, and on short turf. The species feeds mainly on flying fish eggs, squid, fish and crustaceans (Harrison et al. 1983), but also on fish offal and human refuse (Cousins 1998, Conners 2015). During both the incubation and the chick-rearing periods, birds nesting on Tern Island forage widely throughout the North Pacific, including to the distant, productive California Current waters along the west coast of North America (Fernandez et al. 2001, Kappes et al. 2010). In contrast, during the brooding period, birds from Tern Island forage predominantly within 500 to 800 km of the island (Hyrenbach et al. 2002, Conners et al. 2015, Gutowsky et al. 2015, Kappes et al. 2015).
Incidental capture in commercial fisheries represents a threat to the majority of the population. Between 1978 and 1992, the population experienced elevated mortality from interactions with high seas drift-nets in the North Pacific (Johnson et al. 1993). The estimated bycatch rates of Black-footed Albatrosses has fluctuated over the past 50 years, generally ranging between 6,000 and10,000 birds per annum (Naughton et al. 2007); in 2003, mortality was estimated to be at least 2,000 birds per year in the U.S. pelagic longline fleet based in Hawaii, and a further 6,000 in Japanese and Taiwanese fleets (Lewison and Crowder 2003). Recent observer data from the Hawaii longline fisheries, from 2010 to 2015 indicate that deep-set longlines captured an estimated 66 to 535 individuals each year and shallow-set longlines captured an observed 19-49 individuals per year. It has been recently estimated that on average 227 individuals are taken annually in the Alaskan federal groundfish and Pacific Halibut Hippoglossus stenolepis fisheries (in the Bering Sea and Aleutian Islands, and the Gulf of Alaska Fishery Management Plan areas), which also target Pacific Cod Gadus microcephalus and Sablefish Anoplopoma fimbria. Along the west coast of the U.S.A., Black-footed Albatrosses interacting with fleets harvesting Sablefish and Pacific Hake Merluccius productus are exposed to an elevated mortality risk (Guy et al. 2013). In 2012, it was estimated that between 2006 and 2009, from 25 to 128 albatrosses (assumed to all be Black-footed Albatross) were taken annually in Canada’s Pacific demersal longline groundfish fisheries, with a predicted yearly average mortality of 85 birds (DFO 2012). Bycatch rates in the Japanese and Taiwanese longline fleets are largely unknown. However, studies on this species have confirmed the impact of fisheries bycatch on survival (Verán et al. 2007) and the annual population growth rate (Niel and Lebreton 2005). Tracking studies show that post-breeding birds disperse over large distances to the oceanographic 'transition zone' where they are susceptible to bycatch in the various pelagic longline fleets (Hyrenbach and Dotson 2003, BirdLife International 2004, Hyrenbach et al. 2006, Zydelis et al. 2011, Gutowsky et al. 2014, 2015). Within this area, tracking revealed that fishing effort was heavy in the habitats utilised by the species, and that there may be a male bias in the individuals affected by bycatch.
Around the turn of the 20th century, the species suffered sharp declines due to feather hunting (Spennemann 1998). Protective measures and the cessation of feather hunting allowed the population to recover (ACAP 2010).
Climate change poses an ongoing threat in terms of storms and flooding, and a future threat in terms of habitat alteration. The vast majority of the world population nests on islands below 10 m, above sea-level and it is predicted that with climate change and the resulting rise in sea-level, there will be significant inundation and loss of low-lying atolls/islands that are currently used for nesting (Storlazzi et al. 2013, Reynolds et al. 2015).Other potential threats include volcanic eruptions (Harrison 1990), pollution from agricultural effluents and solid waste including organochlorine (Jones et al. 1996, Auman et al. 1997, Guruge et al. 2001), mercury, PCB and DDE (Ludwig et al. 1998, Guruge et al. 2001, Finkelstein et al. 2006, 2007) and oil spills (Fefer et al. 1984, NOAA 1992).
Conservation Actions Underway
All Hawaiian breeding localities are part of the U.S.A. National Wildlife Refuge, the U.S.A. Marine National Monument system or State of Hawaii Seabird Sanctuaries. In 1991, a 50 Nautical Mile (92.6 km) Protected Species Zone was established around the Northwestern Hawaiian Islands, where longline fishing is prohibited. In 2006, the Papahānaumokuākea Marine National Monument was established. Originally, Papahānaumokuākea protected an area of 362,073 km2; in August 2016, the National Marine Monument was expanded to 1,508,870 km2 and increasing the area in which the birds are protected from exposure to fisheries interactions (http://www.papahanaumokuakea.gov/news/expansion_announcement.html).
Nearly 80% of the breeding population is counted directly or sampled every year. All sites except one have been surveyed since 1991 (Croxall and Gales 1998). Hawaiian longline fishing vessels are required to use a range of measures to reduce seabird bycatch. In 2001 and 2007, respectively, the USA and Canada released National Plans of Action to reduce the bycatch of seabirds in longline fisheries (NMFS 2001, DFO 2007). In 2002, the use of bird-scaring (or Tori) lines became a mandatory condition of licence in commercial halibut, sablefish and rockfish (Sebastes spp.) longline fisheries on Canada’s Pacific waters (DFO 2007). In 2006, the Committee on the Conservation of Endangered Wildlife in Canada (COSEWIC) assessed Phoebastria nigripes as Special Concern (a species at risk of becoming threatened or endangered) in Canada (COSEWIC 2006); and in 2009, the species was added to Schedule 1 of Canada’s Species at Risk Act, also as Special Concern (https://www.registrelep-sararegistry.gc.ca/species/speciesDetails_e.cfm?sid=991).
In 2017, the first cohort of 15 Black-footed Albatross chicks from Midway Atoll National Wildlife Refuge were translocated to James Campbell National Wildlife Refuge on the island of O’ahu in Hawaii as part of a plan to establish safe breeding colonies on high islands less at risk from loss due to inundation caused by climate change factors such as sea level rise and increased storm frequency and intensity.
In 2006, the Western and Central Pacific Fisheries Commission passed a measure to require large tuna and swordfish longline vessels to use at least two seabird bycatch mitigation measures when fishing north of 23o N. The Fishing Vessel Owners' Association, which represents the longlining captains in the halibut and sablefish fisheries along the west coast of the U.S.A., has instructed its members to use streamer lines when fishing in Washington, Oregon and Californian waters.
Conservation Actions Proposed
Continue monitoring of population trends and demographic parameters. Continue tracking studies to assess temporal and spatial overlap with longline fisheries (e.g. Zydelis et al. 2011). Adopt best-practice mitigation measures in longline fisheries within the species' range. Re-evaluate the location of the current boundary (23o N) for required use of seabird mitigation measures in the pelagic longline fisheries in the U.S.A. (Hyrenbach and Dotson 2003).
Identification. 68-74 cm. Small, all dark albatross, uppertail coverts normally white. Dark bill, dark legs. Juvenile, even more uniform brown. Similar species. None within range.
Text account compilers
Butchart, S., Calvert, R., Flint, B., Gales, R., Gilman, E., Harrison, C., Lewison, R., Misiak, W., Mitchell, L., Moreno, R., Morgan, K., Nel, D., Nisbet, I., Phillips, R., Rivera, K., Shaffer, S.A., Small, C., Sullivan, B., Symes, A. & Taylor, J.
BirdLife International (2023) Species factsheet: Phoebastria nigripes. Downloaded from http://www.birdlife.org on 27/01/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 27/01/2023.