[MARMAM] paper on scaling pup counts up to abundance estimates for grey seals
mel at mcs.st-andrews.ac.uk
Tue Jun 28 00:47:39 PDT 2011
An Approximate Bayesian Method Applied to Estimating the Trajectories of
Four British Grey Seal (Halichoerus grypus) Populations from Pup Counts.
by Mike Lonergan, Dave Thompson, Len Thomas and Callan Duck (2011).
Journal of Marine Biology, vol. 2011, Article ID 597424, 7 pages.
For British grey seals, as with many pinniped species, population
monitoring is implemented by aerial surveys of pups at breeding
colonies. Scaling pup counts up to population estimates requires
assumptions about population structure; this is straightforward when
populations are growing exponentially but not when growth slows, since
it is unclear whether density dependence affects pup survival or
fecundity. We present an approximate Bayesian method for fitting pup
trajectories, estimating adult population size and investigating
alternative biological models. The method is equivalent to fitting a
density-dependent Leslie matrix model, within a Bayesian framework, but
with the forms of the density-dependent effects as outputs rather than
assumptions. It requires fewer assumptions than the state space models
currently used and produces similar estimates. We discuss the potential
and limitations of the method and suggest that this approach provides a
useful tool for at least the preliminary analysis of similar datasets.
JMB is open access, so anyone interested should be able to get the paper
Please email me if there are any problems about getting, or with, the paper.
NERC Sea Mammal Research Unit,
Scottish Oceans Institute,
University of St Andrews
"The University of St Andrews is a charity registered in Scotland : No SC013532"
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