Journal ArticleDOI
Modelling the impact of fishery by-catches on albatross populations
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This paper developed a deterministic, density-dependent, age-structured model for assessing the effects of longlining on wandering albatross populations and found that the marked decline in both populations, and subsequent recovery of the Crozet Islands population (but not the continued decline of the South Georgia population), can be explained by the tuna longline by-catch.Abstract:
Summary
1 Several albatross species, including the wandering albatross Diomedea exulans, have shown marked declines in abundance throughout their range. These seabirds are frequently taken as by-catch in longline fisheries and this mortality has been implicated in the population declines. 2 We developed a deterministic, density-dependent, age-structured model for assessing the effects of longlining on wandering albatross populations. We used demographic data from field studies at South Georgia and the Crozet Islands, data on albatross abundance from 1960 to 1995, and reported effort data from the tuna longline fisheries south of 30° S, to model estimated by-catch levels and other population parameters in the model.
3 The model used two alternative assumptions about patterns of at-sea distribution of wandering albatross (uniform between 30° S–60° S; proportional to the distribution of longline fishing effort between these latitudes).
4 Our model was able to predict reasonably closely the observed data from the Crozet Islands wandering albatross population, but the fit to the South Georgia population was substantially poorer. This probably reflects: (i) greater overlap in the Indian Ocean than in the Atlantic Ocean between the main areas of tuna longline fishing and the foraging ranges of wandering albatrosses from the Crozet Islands and South Georgia, respectively; and (ii) greater impact of poorly documented longline fisheries, especially the tuna fisheries in the south Atlantic and the Patagonian toothfish Dissostichus eleginoides fishery, within the foraging range of wandering albatrosses from South Georgia.
5 The model results suggest that the marked decline in both populations, and subsequent recovery of the Crozet Islands population (but not the continued decline of the South Georgia population), can be explained by the tuna longline by-catch. They further indicate that populations may be able to sustain some level of incidental take. However, the likely under-reporting of fishing effort (especially in non-tuna longline fisheries) and the delicate balance between a sustainable and unsustainable level of by-catch for these long-lived populations suggest great caution in any application of such findings.read more
Citations
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Quantifying the effects of fisheries on threatened species: the impact of pelagic longlines on loggerhead and leatherback sea turtles
TL;DR: A bycatch assessment for loggerhead and leatherback sea turtles that are incidentally caught by global pelagic longlines is presented and it is suggested that thousands of these turtles die each year from longline gear in the Pacific Ocean alone.
Journal ArticleDOI
Measuring Global Trends in the Status of Biodiversity: Red List Indices for Birds
Stuart H. M. Butchart,Alison J. Stattersfield,Leon Bennun,Sue M Shutes,H. Resit Akçakaya,Jonathan E. M. Baillie,Simon N. Stuart,Craig Hilton-Taylor,Georgina M. Mace +8 more
TL;DR: A method for producing indices based on the IUCN Red List to chart the overall threat status (projected relative extinction risk) of all the world's bird species from 1988 to 2004 is presented.
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Climate change and Southern Ocean ecosystems I: how changes in physical habitats directly affect marine biota
Andrew J. Constable,Andrew J. Constable,Jessica Melbourne-Thomas,Jessica Melbourne-Thomas,Stuart Corney,Kevin R. Arrigo,Christophe Barbraud,David K. A. Barnes,Nathaniel L. Bindoff,Nathaniel L. Bindoff,Nathaniel L. Bindoff,Philip W. Boyd,Philip W. Boyd,Angelika Brandt,Daniel P. Costa,Andrew T. Davidson,Andrew T. Davidson,Hugh W. Ducklow,Louise Emmerson,Mitsuo Fukuchi,Julian Gutt,Mark A. Hindell,Eileen E. Hofmann,Graham Hosie,Graham Hosie,Takahiro Iida,Sarah Jacob,Nadine M. Johnston,So Kawaguchi,So Kawaguchi,Nobuo Kokubun,Philippe Koubbi,Mary-Anne Lea,Azwianewi B. Makhado,Robert A. Massom,Robert A. Massom,Klaus M Meiners,Klaus M Meiners,Michael P. Meredith,Eugene J. Murphy,Stephen Nicol,Stephen Nicol,Keith Reid,Kate Richerson,Martin J. Riddle,Stephen R. Rintoul,Stephen R. Rintoul,Walker O. Smith,Colin Southwell,Colin Southwell,Jonathon S. Stark,Michael D. Sumner,Kerrie M. Swadling,Kunio T. Takahashi,Phil Trathan,Dirk Welsford,Henri Weimerskirch,Karen J. Westwood,Karen J. Westwood,Barbara Wienecke,Dieter Wolf-Gladrow,Simon W. Wright,Simon W. Wright,José C. Xavier,José C. Xavier,Philippe Ziegler +65 more
TL;DR: Current and expected changes in ASO physical habitats in response to climate change are reviewed, including how these changes may impact the autecology of marine biota: microbes, zooplankton, salps, Antarctic krill, fish, cephalopods, marine mammals, seabirds, and benthos.
Journal ArticleDOI
Threats to seabirds: A global assessment
Maria P. Dias,Rob W. Martin,Elizabeth J. Pearmain,Ian J. Burfield,Cleo Small,Richard A. Phillips,Oliver Yates,Ben Lascelles,Pablo García Borboroglu,Pablo García Borboroglu,John P. Croxall +10 more
TL;DR: In this paper, the authors present the first objective quantitative assessment of the threats to all 359 species of seabirds, identify the main challenges facing them, and outline priority actions for their conservation.
References
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Book
Quantitative Fish Dynamics
TL;DR: The results show clear trends in population growth, Mortality, and the Fishing Process, and age Structured Models: Renewal Theory and Assessment Methods show clear patterns in growth, mortality, and migration.
Journal ArticleDOI
Satellite tracking of Wandering albatrosses
TL;DR: The first successful tracking of a bird using satellite telemetry was described in this article, which showed that the birds covered between 3,600 and 15,000 km in a single foraging trip during an incubation shift.
Journal ArticleDOI
Foraging Strategy of Wandering Albatrosses Through The Breeding Season: A Study Using Satellite Telemetry
TL;DR: It is shown that Wandering Albatrosses use two foraging strategies to cope with the constraints imposed by the different stages of the breeding cycle, the availability of prey, and the distribution of the prey.
Journal ArticleDOI
Population dynamics of wandering albatross Diomedea exulans and Amsterdam albatross D. amsterdamensis in the Indian Ocean and their relationships with long-line fisheries: Conservation implications
TL;DR: In this article, a demographic study of the Crozet population indicates that the earlier decline was mainly the result of increased adult mortality and secondarily of low recruitment, and that decreased fishing effort and a concentration outside the central Indian Ocean by the Japanese fishery during recent years has probably resulted in the slow recovery of these albatross populations as a result of improved adult survival and recruitment.
Journal ArticleDOI
Reproductive effort in long-lived birds : age-specific patterns of condition, reproduction and survival in the wandering albatross
TL;DR: It is suggested that in a very long-lived bird like the wandering albatross survival is not influenced by reproduction, particularly in the early ages because the onset of breeding is delayed until the risk of an increased mortality at first breeding has disappeared.
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