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. doi:10.1155/2011/597424 Abstract 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 here: http://www.hindawi.com/journals/jmb/2011/597424/ Please email me if there are any problems about getting, or with, the paper. Cheers, Mike. -- Mike Lonergan 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"