Albatross Phoebastria Albatrus Research Articles

Incomplete isolation in the nonbreeding areas of two genetically separated but sympatric short-tailed albatross populations

The short-tailed albatross Phoebastria albatrus, a globally Vulnerable species recovering from near-extinction, breeds mainly on 2 island groups in the north-western Pacific: Torishima and Senkaku Islands. Recently, it became clear that this is a species complex, composed of 2 populations (‘Torishima’ and ‘Senkaku’ types) that are distinct from both genetic and morphological perspectives, and which mate assortatively on Torishima. We tested the hypothesis of premating isolation as a possible mechanism for genetic differentiation and shifted breeding date in short-tailed albatrosses. Using light-based geolocation and molecular analysis, we examined whether adults from the 2 populations breeding on Torishima differed in their at-sea distribution during the nonbreeding period (June-September) and in their return dates. From 22 bird tracks collected from 12 birds over 4 yr, we identified 2 distinct nonbreeding areas: around the Aleutian Islands in the Bering Sea and near the Kuril Islands in the Okhotsk Sea. All 6 tracks of Torishima-type birds migrated directly to the Bering Sea in all years. In contrast, most of the Senkaku-type birds migrated along northeast Japan to the Okhotsk Sea (9 tracks), with the others moving to the Bering Sea (7 tracks). There was no clear difference in the dates of return to Torishima between the 2 bird types. Overall, no absolute pre-mating isolation in space or time was observed in short-tailed albatrosses, but we highlighted notable divergences in the nonbreeding distribution of both types. This result suggests that Torishima- and Senkaku-type populations should be treated as separate management units.

Neotype designation of the Short-tailed Albatross Phoebastria albatrus (Pallas, 1769) (Aves: Procellariiformes: Diomedeidae).

The Short-tailed Albatross Phoebastria albatrus (Pallas, 1769) is a threatened seabird widely distributed in the northern Pacific Ocean with its largest breeding sites on the Senkaku Islands and Torishima Island, Japan, which are separated by over 1700 km. A recent taxonomic revision based on morphological, behavioral, and DNA sequence evidence has revealed that this species consists of two cryptic species: a smaller species which breeds mainly in the Senkaku Islands, and a larger species which breeds mainly on Torishima Island. However, it has remained unclear to which of these species the scientific name Phoebastria albatrus applies, because the type specimens are lost. Here a neotype is designated to resolve this taxonomic issue. From now on, the scientific name Phoebastria albatrus should be applied only to the smaller species breeding on the Senkaku Islands. The name of the larger species is more problematic, as the types of each synonym of P. albatrus must be traced, found, and examined.

Long-term declines in common breeding seabirds in Japan

SummaryGlobal seabird populations are in decline, with nearly half of all seabird species currently in an extinction crisis. Understanding long-term seabird population trends is an essential first step to inform conservation actions. In this study, we assembled historical breeding records of seabirds throughout the Japanese archipelago and quantified the long-term population trends of 10 major breeding seabird species using a hierarchical Bayesian state-space model. The model revealed that six species had increasing or no detectable trends (Short-tailed Albatross Phoebastria albatrus, Leach’s Storm Petrel Oceanodroma leucorhoa, Pelagic Cormorant Phalacrocorax pelagicus, Japanese Cormorant Phalacrocorax capillatus, Spectacled Guillemot Cepphus carbo, and Rhinoceros Auklet Cerorhinca monocerata). However, decreasing trends were found not only in nationally threatened species (Common Murre Uria aalge, and Tufted Puffin Fratercula cirrhata) but also common species that are often described as abundant (Black-tailed Gull Larus crassirostris and Slaty-backed Gull Larus schistisagus). These declining species have declined to 3–35% of baseline levels over the past 30 years. This study provides the first evidence of long-term declines in common and widespread seabirds in Japan.

Maturation of Plumage in the Short-tailed Albatross <i>Phoebastria albatrus</i> Based on Birds of Known Sex and Age on Torishima

To facilitate the accurate description of plumage of the Short-tailed Albatross Phoebastria albatrus, we classified plumage into eight components, based on photos taken at a breeding colony on Torishima, Izu Islands. Plumage components of 20 individuals just before fledging and 729 individuals of known sex and ranging in age from 2 to 26 years were scored. The plumage color became more whitish with age. The underbody plumage became white earlier than the upper body, whereas on the thigh, tibia and a posterior part of undertail coverts, dark brown feathers remained even in older age. The upper body turned white from the uppertail coverts towards the front, whereas dark brown feathers remained on the mantle, scapulars and nape, even in older age. The upperwing and underwing were often the same score. The progress of the score was earlier for males than for females. At every age from 3 to 18 years, the summed score of seven components (the underwing score was excluded) was significantly different between sexes, although older age males and females could be considered to have the same score. Individuals with a dark brown mantle, scapulars, rump and uppertail coverts were of age of 5 or less years and had not yet bred, except for a few females. Many individuals started breeding after they had a white part on the rump and uppertail coverts. Males reached final plumage pattern at the age of 8 to 15 years, while females reached final plumage pattern at the age of 11 to 20 years or older.

Ontogenetic changes in at-sea distributions of immature short-tailed albatrosses Phoebastria albatrus

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 35:23-37 (2018) - DOI: https://doi.org/10.3354/esr00864 Theme Section: Biologging in conservation Ontogenetic changes in at-sea distributions of immature short-tailed albatrosses Phoebastria albatrus Rachael A. Orben1,*, Amelia J. O’Connor2, Robert M. Suryan1,3, Kiyoaki Ozaki4, Fumio Sato4, Tomohiro Deguchi4 1Department of Fisheries and Wildlife, Oregon State University, Hatfield Marine Science Center, 2030 SE Marine Science Drive, Newport, Oregon 97365, USA 2College of Earth, Ocean, and Atmospheric Science, Oregon State University, 104 CEOAS Administration Building, Corvallis, Oregon 97331, USA 3NOAA Fisheries, Alaska Fisheries Science Center, Auke Bay Laboratories, Ted Steven's Marine Research Institute, 17109 Pt. Lena Loop Rd., Juneau, Alaska 99801, USA 4Division of Avian Conservation, Yamashina Institute for Ornithology, 115 Konoyama, Abiko, Chiba 270-11, Japan *Corresponding author: raorben@gmail.com ABSTRACT: The ability of juveniles of wide-ranging species to locate distant foraging regions can rely on innate or learned information. Reliance on innate cues could be problematic when conservation actions facilitate reintroduction. In the North Pacific, the short-tailed albatross Phoebastria albatrus is recovering from extensive harvesting, and has recently benefited from translocation efforts. Yet little is known about how naïve juveniles disperse or about individual distributions of immature short-tailed albatrosses. The primary goals of this study were to quantify the ontogeny of movement patterns and spatial distributions and compare these between naturally reared and translocated short-tailed albatrosses. We tracked 51 albatrosses for up to 5 years post-fledging: naturally reared chicks from their natal colony on Torishima, Japan, and chicks that were translocated 350 km to the southeast to Mukojima, Japan. Initial, more northerly dispersal of translocated fledglings suggests the ability to adjust to a new departure location. Fledglings’ departure paths differed from previously tracked adults departing Torishima, yet like adults, the majority of fledglings (81%) reached the Bering Sea that first summer, further supporting large-scale innate orientation abilities. Juveniles showed strong seasonal changes in distributions, traveling more in winter and occupying regions not typically used by adults (e.g. California Current, Sea of Okhotsk). As they aged, juveniles began to exhibit habitat fidelity to shelf-break regions, as anticipated from prior studies, yet continued to explore new regions with low levels of spatial fidelity. Juvenile short-tailed albatrosses explored almost the entire species range, highlighting the impressive capacity of individuals to transverse the North Pacific. KEY WORDS: Post-fledging migration · Juvenile distribution · Dispersal · Year-round tracking · Seabird · Home range · Albatross · GPS tracking Full text in pdf format Supplementary material PreviousNextCite this article as: Orben RA, O’Connor AJ, Suryan RM, Ozaki K, Sato F, Deguchi T (2018) Ontogenetic changes in at-sea distributions of immature short-tailed albatrosses Phoebastria albatrus. Endang Species Res 35:23-37. https://doi.org/10.3354/esr00864 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 35. Online publication date: January 15, 2018 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2018 Inter-Research.

Assortative mating in two populations of Short‐tailed Albatross Phoebastria albatrus on Torishima

Assortative mating is an important pre‐mating isolation mechanism that has been observed in some wild populations of seabirds. The Short‐tailed Albatross Phoebastria albatrus is a globally Vulnerable seabird that breeds mainly on Torishima and the Senkaku Islands in the north‐western Pacific Ocean. Our previous studies suggested that two genetically distinct populations exist, one on Torishima and the other on the Senkaku Islands. Recently, however, several un‐ringed birds in subadult plumage have been observed breeding on Torishima in the Hatsunezaki colony. As almost all birds hatched on Torishima since 1979 have been ringed, the natal site of the un‐ringed birds was suspected to be the Senkaku Islands. Genetic differences between the two populations would reveal the natal sites of un‐ringed birds. By observing the ring status (ringed or un‐ringed) of mating pairs and analysing the mitochondrial DNA (mtDNA) control region 2 of un‐ringed birds, we assessed whether birds that originated from Torishima and the Senkaku Islands achieved pre‐mating isolation. There was a small number of pairs on Torishima that consisted of one ringed and one un‐ringed bird, but the observed number was significantly lower than that expected if ringed and un‐ringed birds mated randomly. Furthermore, mtDNA analyses of nine un‐ringed birds demonstrated that all belonged to a particular haplotype clade from the Senkaku Islands. These results show that birds from Torishima and the Senkaku Islands mate assortatively but that there is incomplete pre‐mating isolation between birds from the two island groups. The pre‐mating isolation of these two populations of Short‐tailed Albatross could arise from differences in the timing of breeding and incompatibility in mating displays. As the divergence between the two populations is unlikely to be sufficient to achieve complete post‐mating isolation, the two groups are likely to be hybridizing. Further studies using molecular and/or behavioural analyses would be required to reveal the evolutionary significance of hybridization between these two populations.

Translocation and hand-rearing of the short-tailed albatross Phoebastria albatrus: early indicators of success for species conservation and island restoration

AbstractMany endemic species, particularly those on remote islands, have been driven to extinction or near extinction by anthropogenic influences. The short-tailed albatross Phoebastria albatrus once numbered in the millions but was thought to be extinct by the mid 20th century. Albatrosses, of the family Diomedeidae, are among the most threatened birds globally as a result of commercial exploitation, introduced predators, and mortality in commercial fisheries. We applied an experimental approach over 5 years to evaluate the translocation and hand-rearing of albatross chicks by comparing growth, physiological health indices, post-fledging survival, and migration patterns with a control group of naturally reared chicks in the source population. Hand-reared chicks had comparable or superior health and similar rates of immediate post-fledging mortality (15%), with mortality strongly female-biased in both groups. Hand-reared birds had longer post-fledging drift periods before attaining sustained flight (also female-biased) but comparable, albeit somewhat wider ranging, migration patterns to naturally reared chicks during their first 6 months at sea. Recruitment to the translocation site of a breeding pair that included a hand-reared bird occurred within 5 years of the first translocation. Success will ultimately depend on continued recruitment and breeding over the coming decades, given delayed breeding in these long-lived species. The results to date, however, have exceeded initial expectations and can inform potential reintroductions of other long-lived, migratory avian species with strong natal philopatry, and reintroductions of native species to former breeding islands.

Inferring the ancient population structure of the vulnerable albatross Phoebastria albatrus, combining ancient DNA, stable isotope, and morphometric analyses of archaeological samples

The history of population structure is a key to effective wildlife management and conservation. However, inferring the history of population structure using present genetic structures is problematic when the method is applied to species that have experienced severe population bottlenecks. Ancient DNA analysis seemed to be a promising, direct method for inferring ancient population structures. However, the usual methods for inferring modern population structure, i.e. the phylogeographic approach using mitochondrial DNA and the Bayesian approach using microsatellite DNA, are often unsuitable for ancient samples. In this study, we combined ancient DNA obtained from zooarchaeological bones with carbon/nitrogen stable isotope ratios and morphological variations to infer ancient population structure of the short-tailed albatross Phoebastria albatrus. The results showed that the bird existed in two populations, between which the genetic distance was greater than that of distinct sister albatross species, although no subspecies of P. albatrus have been proposed. Our results suggest that the birds at the present two breeding regions (Torishima in the Izu Islands and two islets of the Senkaku Islands) are descended from these two ancient populations, and that reevaluation of the status and conservation strategy for the species is required. Our results also indicate that lineage breeding on the Senkaku Islands has drastically reduced genetic diversity, while that on Torishima has not. The approach proposed in this study would be useful for inferring ancient population structure, using samples of highly mobile animals and/or samples from archaeological sites, and the reconstructed ancient population structure would be useful for conservation and management recommendations.

Unexpectedly high genetic diversity of mtDNA control region through severe bottleneck in vulnerable albatross Phoebastria albatrus

In the late part of the nineteenth century and the early part of the last century, the short-tailed albatross Phoebastria albatrus was in danger of extinction owing to feather hunting. In the middle of the last century, the total number of this species was inferred to be approximately 50-60 with breeding occurring only on Torishima Island of the Izu Islands. Recently, the number of individuals has increased to more than 2,000 and that of their breeding islands to three, namely, Torishima Island, and Minami- and Kita-kojima Islands of the Senkaku Islands. Here, we show that the 44 short-tailed albatrosses we examined represent 29 haplotypes in the control region of mitochondrial DNA, and have a considerably higher genetic diversity than most avian species, but not very high in albatross species; the h and π were 0.96 and 0.013, respectively. However, the parsimony network clearly showed that many intermediate haplotypes were lost. It was concluded that the majority of the haplotypes in the founder population have been maintained. Judging from these findings and the exponential increase in the number of individuals, the present population of the short-tailed albatross seems not to be affected by inbreeding depression through a severe bottleneck. The conservation and expansion of their breeding grounds, and effective protection from bycatch mortality in foraging areas are important for the future survival of this species.

A new species of shearwater of the genus Calonectris (Aves: Procellariidae) from a middle Pleistocene deposit on Bermuda

ABSTRACT Remains of at least 26 individuals of a Calonectris shearwater were recovered from a Pleistocene beach deposit on Bermuda that formed when sea-level was more than 21 m above present level during an interglacial (Marine Isotope Stage 11) 400,000 yr ago. Two prefledging juveniles in the sample indicate breeding on the island. This shearwater was the general size of C. d. diomedea of the Mediterranean but differs in proportions and in qualitative characters and is described as Calonectris wingatei, new species. The species appears to have become extinct shortly after the time of deposition, when rising sea-level is also thought to have caused the extinction of the Short-tailed Albatross Phoebastria albatrus on Bermuda. The Neogene history of the taxa of Calonectris in the Atlantic basin is examined in the context of major geological and oceanographic events.

船舶調査から推定した日本周辺におけるアホウドリの海上生息域

The pelagic distribution of the Short-tailed Albatross Phoebastria albatrus in the western North Pacific o# the Nansei Islands to eastern Japan was examined from data collected by research vessels from 1999 to 2004. Fifteen groups and 325 individuals of Short-tailed Albatrosses were recorded during line-transect sighting surveys, and 25 groups and 45 individuals were recorded in opportunistic observations during cruising, drifting and experimental fishing. Results of the sighting survey revealed that Short-tailed Albatrosses appeared in three areas o# Japan from the fourth quarter to the next second quarter: 1) o# the Pacific coast of eastern Japan, 2) near Torishima of the Izu Islands, and 3) near Minamikojima of the Senkaku Islands. Geographical analysis of the occurrence points showed that large numbers of Short-tailed Albatrosses aggregated in the near-shore waters within 30 km of the breeding islands, and that they also utilized the Kuroshio Oyashio mixture zone above the continental shelf edge and slope 2001400 m in depth and 2070 km o#shore of the Pacific coast of eastern Japan. Results of this study suggest that ar esting area near the breeding islands and a foraging area above the continental slope o# eastern Japan are important marine habitats for the Short-tailed Albatross during the breeding period.

Determining spatial and temporal overlap of an endangered seabird with a large commercial trawl fishery

Spatial and temporal overlap between the short-tailed albatross Phoebastria albatrus, an endangered species, and the Alaskan groundfish trawl fleet is of concern because of the potential for incidental mortality. Due to the small size of this albatross population (ca. 2000 birds) and their wide-ranging foraging behavior, opportunistic sightings contribute the majority of the data on their distribution. In contrast, detailed information exists on fishing effort. In this study, 2 methods were used to predict albatross distributions: (1) bounded interpolation of sightings and (2) distance to the 1000 m isobath. The fishery was grouped into 5 sectors based on fish processing mode and predomi- nant product type. Locations and durations of observed trawls were associated with the predicted albatross densities and overlap was quantified using 2 metrics. Spatial and temporal overlap of alba- trosses and the trawl fleet was influenced by the assumptions used to infer albatross distribution and also differed among trawl sectors depending on the metric used to calculate overlap. The sectors with the highest and lowest overlap changed seasonally. In general, overlap scores were lowest in winter and spring due to both low trawl effort (in winter) and low albatross sightings (winter and spring). Relative effort in trawl sectors, in addition to proximity to high predicted albatross densities, con- tributed to overlap rankings such that some sectors with greater effort in areas with lower predicted albatross density had higher overlap scores than sectors with less effort in areas with high predicted albatross densities.