Phytoplankton algae in transitional and coastal waters
Assessment made on 01 May 2004
ClassificationWater (Primary theme)
Coasts and seas
- WEU 014
Policy issue: Is the condition regarding eutrophication of Europe's seas improving?
Since the 1970s, the harmful algae phenomenon has increased throughout the world. There is no clear trend in shellfish poisoning events in European waters for diarrheic shellfish poisoning (DSP), and paralytic shellfish poisoning (PSP). Amnesic shellfish poisoning (ASP) occurrences seem to occur more frequently than in the past.
Occurrence of harmful algae, which are widely distributed in marine and coastal waters, does not necessary means poisoning events. Understanding of interactions between physical and biological processes leading to harmful blooms presently is an active field of research. In addition to that, monitoring of poisoning events used to be focussed on shellfish production areas. This is important to keep in mind when assessing the results, and specially through maps as presented below. Levels and trends (figure 1) of shellfish poisoning events are presented in figure 1. The data come from the HAEDAT database, which includes extensive additional information about the poisoning events. The data are updated by the international Working Group on Harmful Algal Bloom Dynamics (WGHABD), under the joint responsibility of the International Council for the Exploration of the Sea (ICES) and the Intergovernmental Oceanographic Commission (IOC) of UNESCO.
Over the 1989 to 1998 period for Europe, ASP events are the less frequent with only five years of occurrence and one peak of more than 5 events (in 1998). Recent indications tend to show that ASP poisoning is increasing. Events have been recorded in France in 2000, which was never the case before. PSP events are regularly observed. Their numbers were particularly high over the 1993-1996 period. DSP is the most common type of poisoning observed with a number of events always over five.
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