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Marnix
Poelman, Nederlands Instituut voor Visserij Onderzoek, Centre for Shellfish
Research P.O.Box 77, 4400 AB Yerseke, The NetherlandsMarnix
Poelman, Nederlands Instituut voor Visserij Onderzoek, Centre for Shellfish
Research P.O.Box 77, 4400 AB Yerseke, The Netherlands
The lack of sufficient amounts of mussels (seed and consumption) necessitates the Dutch mussel industry to “import” mussels from other countries. Translocation of material (water, shellfish, sediment) from one ecosystem to another results in a risk of introduction of exotic organisms. The Dutch authorities have therefore enforced legislation on the “import” of mussels to prevent the introduction of exotic organisms into Dutch waters. The legislation focuses on several aspects such as the geographical situation of the harvesting area (boreal or non-boreal area), the abundance of shellfish disease and the presence of toxic dinoflagellates. The principle of a large part of the legislation lies in the prevention of introductions of toxic dinoflagellates (e.g., Alexandrium tamarense, A. acatanella, A.catanella, A. fundyense). These species are present worldwide and result in extensive harmful algal blooms (HAB), some of which are called red tides. After a bloom these species produce cysts (survival stage), which are deposited on the bottom and remain in the sediment up to 10-15 years. At favourable environmental conditions the cysts may start a new bloom. Next to the undesired ecological effects associated with the introduction of HAB species, there are also potential health effects related to the toxic dinoflagellates. The dinoflagellates may produce Paralytic Shellfish Toxin, which are toxins that can accumulate in shellfish and cause severe health effects when consumed. The legislation on the import of shellfish is a multi-disciplinary tool, which will prevent or minimise the risks of an introduction of toxic dinoflagellates, and thus protect the ecosystem and the shellfish production sites from a reoccurring harmful algal bloom.
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