Retrospective population analyses and related future management perspectives for the harbour seal Phoca vitulina in the Wadden Sea
Reijnders, P.J.H. (1992). Retrospective population analyses and related future management perspectives for the harbour seal Phoca vitulina in the Wadden Sea, in: Dankers, N.M.J.A. et al. Present and future conservation of the Wadden Sea: Proceedings of the 7th International Wadden Sea Symposium, Ameland 1990. Publication Series. Netherlands Institute for Sea Research (NIOZ), 20: pp. 193-197
In: Dankers, N.M.J.A.; Smit, C.J.; Scholl, M. (Ed.) (1992). Present and future conservation of the Wadden Sea: Proceedings of the 7th International Wadden Sea Symposium, Ameland 1990. Publication Series. Netherlands Institute for Sea Research (NIOZ), 20. Netherlands Institute for Sea Research (NIOZ): Texel. VIII, 301 pp., meer
In: Publication Series. Netherlands Institute for Sea Research (NIOZ). NIOZ: Den Burg. ISSN 0923-330X, meer
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Documenttype: Congresbijdrage
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| Abstract |
Seals in the Wadden Sea have been subject to hunting pressure for centuries. In most countries, often promoted by bounty systems, some form of hunting statistics is available. Annual mortality, due to hunting, is used to estimate historical population size. Based on ranges for most likely rates of increase corresponding trajects for population trends are calculated. Since about 1960, aerial surveys are carried out in most areas. Those data are compiled and provide data on the changes in population size up to the present. The future developments of the harbour seal population are estimated by using a population simulation model. Next to gradual changes in vital population parameters, trends will be strongly dominated by the fact whether or not recurrent seal plagues will occur. It is elucidated that the outcome of the revised retrospective population analysis will be an important prerequisite to define management objectives for a rebuilding harbour seal population in the Wadden Sea. |
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