J. Mees et Pjh. Reijnders, THE HARBOR SEAL, PHOCA-VITULINA, IN THE OOSTERSCHELDE - DECLINE AND POSSIBILITIES FOR RECOVERY, Hydrobiologia, 283, 1994, pp. 547-555
Within a timespan of a few decades, the harbour seal almost completely
disappeared from the estuaries in the south-west of the Netherlands.
In 1960 a population of around 350 animals still lived in the Oostersc
helde and Westerschelde area. About a quarter of this population lived
in the Oosterschelde. At present less than 17 animals can be regularl
y observed in the whole area. Human influences are responsible for the
rapid decline of the population. Initially a high hunting pressure an
d later environmental pollution are the main causes. Loss of habitat a
nd disturbance at the resting places are additional important factors.
The Oosterschelde still is a suitable habitat for seals. A short term
natural development of a viable population in the area is not to be e
xpected. Only with human help through active management, i.e. reintrod
uction of rehabilitated seals (preferably originating from that area)
and strict conservation of the extant Oosterschelde seal population, a
ccompanied by environmental sanitation of the neighbouring waters, can
the current southern Dutch harbour seal population increase.