On 29th April 1991, a subadult female Bottle-nosed Dolphin Tursiops truncatus was found dead in the Ooslerschelde, Zeeland, the Netherlands. It is likely that this was Zeeland’s resident dolphin which appeared in the coastal waters one year earlier. Several other cases of sociable resident dolphins are listed. Bottlenosed Dolphins are virtually extinct in Dutch coastal waters since the 1960s and sightings in the southern North Sea are rare. An influx observed during aerial surveys in June 1990 (28 Bottle-nosed Dolphins in the Dutch sector, including 9 calves) may have been caused by relatively high water temperatures in the warm summer following a mild winter. Ihere may he a link between the influx and the sudden appearance of a resident dolphin, but it may as well have been sheer coincidence.