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Integrated Statistical Modeling for Hawaiian Albatross Populations
Reports (PDF): FY
2007, FY 2006,
FY 2005, FY
2004, FY 2003
Based on a comparative approach, Niel and Lebreton (2001) showed that suspected levels of bycatch for the black-footed albatross were large enough to possibly affect population growth. Similar concerns exist for the Laysan albatross, P. immutabilis, which, although more numerous than black-footed albatross, tends to exhibit large variation in breeding numbers.
Over the years, Laysan and black-footed albatross populations have been monitored in various ways, on a very incomplete and irregular basis. The types of data include banding of chicks, resightings (and band identification) of breeders, censuses on the breeding colonies, and estimates of bycatch. The various sources of demographic information have not yet been combined and appraised in a systematic statistical way to develop a comprehensive assessment of population status for Laysan or black-footed albatross. Furthermore, there are a number of peculiarities in the the demography of these birds which pose special problems for the parameter estimation and modeling, such as late age of maturity, low reproductive output, high adult survival rate, and long term pair bonding behavior.
The combined effect of these complications argues for the need for an integrated statistical modeling approach, in order to make best use of all the available information, while providing realistic quantification of the true uncertainties in the model conclusions and predictions. Integrated modeling is based on the combination of likelihoods corresponding to probability models for all relevant observables and parameters as they are linked by an underlying dynamical model (e.g., Hampton and Fournier, 2001). The purpose of this project is to develop integrated statistical models for black-footed and Laysan albatross populations, with a view to quantifying the effects of past and present levels of bycatch on these species, and to provide a basis for answering the following questions:
researchers will assemble a consensus version of all the pertinent data,
review the existing estimates of demographic parameters, and undertake
further estimates of particular parameters wherever needed to resolve
questions raised in the review. Access to critical data will be obtained
through ongoing cooperative efforts with the U.S. Geological Survey
(USGS), U.S. Fish and Wildlife, the Western Pacific Regional Fishery
Management Council and the Northern Pacific Albatross Working group.
The review of the existing estimates will be conducted in collaboration
with J.D. Nichols of the USGS Patuxent Environmental Research Center
(Laurel, MD) who has recently done survival analyses based on the banding
data and is currently working on a separate but related project on the
demographics of the North Pacific albatross populations.
The responsibility for the two main main components of the project, demographic parameter analysis, and integrated modeling, will be shared by the two groups participating, with a main role of J.D. Lebreton's group on the demography, and of D. Goodman's on the integrated modeling. Project deliverables will be a documented data base, a manuscript giving the results of the review of the demographic parameters, and a report on specifications for the model.
Year 1 funding for this 3-year project to be awarded January 2003.
This page updated August 7, 2008