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Varkensmarkt 9
4101 CK Culemborg
the Netherlands
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In search of elvers

In 2009, we investigated the presence of elvers and young fish at a number of control stations. The aim of the research was to reveal the extent of barriers to migration and to propose mitigation measures.

In the Netherlands, few elvers were observed. Since 1980, the numbers of elvers has shown a rapid decline and fell to around 1-2% of its former levels (compared to average numbers between 1960-1980). We examined the presence of elvers at a number of locations around Utrecht and North-Holland at which elvers would be expected; such as transitional areas between waterways. As elvers migrate at night, sampling involved late-night visits to permanent fyke nets (also known as funnel nets) and netting with the aid of torchlight. Although more than 3,100 fish of 14 species were caught a mere 25 elvers were observed.

Low numbers of elvers were observed partly because the flow of water in DUtch systems no longer follows a natural course. In the case of the IJsselmeer, the water flows into the River Vecht, rather than vice versa. Other waters in the Netherlands have also lost their natural flow. We have, therefore, advised investigations into the effects of unnatural water flow on the migration of fish. We are hereby involved in research in the presence of fish.

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