PROTECTED AREAS IN THE NORTH-SEA - AN ABSOLUTE NEED FOR FUTURE MARINERESEARCH

There are many signals that different human activities affect the mari ne ecosystem on local and sometimes regional scales. There is evidence that in the Dutch sector of the North Sea at least 25 species have de creased tremendously in numbers or have totally disappeared. But what has caused their disappearance: fisheries, pollution, eutrophication, climatic changes, or a combination of causes? On the Dutch Continental Shelf, the fisheries are now so intensive that every square metre is trawled, on an average, once to twice a year. Furthermore, it has been shown that trawling causes direct damage to the marine ecosystem. Thi s indicates that the ''natural'' North Sea ecosystem we are studying i s already a heavily influenced system. And what is the value of data o n the diversity and production of benthic animals, if the research are a has been raked by beamtrawl gear an unknown amount of times before s ampling? To be able to study the natural trends in the marine ecosyste m, or to answer the question which human activity has most influenced the ecosystem, there is an absolute and immediate need for protected a reas to be established. The size of the protected areas must be determ ined by the behaviour of that species characteristic for the area. In such areas, where fisheries and local pollution would be forbidden or very limited, scientific research into the species composition and age distribution of different populations should be carried out and trend s should be established.