Over het archief
Het OWA, het open archief van het Waterbouwkundig Laboratorium heeft tot doel alle vrij toegankelijke onderzoeksresultaten van dit instituut in digitale vorm aan te bieden. Op die manier wil het de zichtbaarheid, verspreiding en gebruik van deze onderzoeksresultaten, alsook de wetenschappelijke communicatie maximaal bevorderen.
Dit archief wordt uitgebouwd en beheerd volgens de principes van de Open Access Movement, en het daaruit ontstane Open Archives Initiative.
Basisinformatie over ‘Open Access to scholarly information'.
Status of marine mammals in the North Sea
Reijnders, P.J.H.; Lankester, K. (1990). Status of marine mammals in the North Sea. Neth. J. Sea Res. 26(2-4): 427-435
In: Netherlands Journal of Sea Research. Netherlands Institute for Sea Research (NIOZ): Groningen; Den Burg. ISSN 0077-7579; e-ISSN 1873-1406, meer
|  |
| Auteurs | | Top |
- Reijnders, P.J.H., meer
- Lankester, K.
|
|
|
| Abstract |
Information on the population status of marine mammals in the North Sea is rather scarce. For Grey Seals and Common Seals, which regularly come ashore, fairly accurate population estimates exist. However for whale species, even the more commonly observed dolphins and Harbour porpoise, no reliable data on stock areas or stock sizes can be provided. Nevertheless, it is assumed that most whale populations have decreased in numbers. And only after cessation of hunting, seal stocks have been increasing in most areas. Major recent and potential threats to marine mammals are interactions with fisheries and pollution. Several aspects of interactions considered are: drowning in nets, damage to nets or catch, 'competition' for fish and marine mammals as hosts for parasites. Most of these issues can only be answered by more intense population studies combined with multispecies fisheries assessments. Observer networks and stranding data can provide useful indices for qualitative occurrence of marine mammals, but are of limited use for proper population analyses. Adequate management of an ecosystem requires understanding of interspecies relationships and the vulnerability of its components to changes in environmental conditions. Data on the status of marine mammals are urgently required to evaluate their role in the marine ecosystem. |
IMIS is ontwikkeld en wordt gehost door het VLIZ.
