Science - November 16, 2017

CBS fine-tunes report on North Sea fauna

Tessa Louwerens

Following criticism from Wageningen Marine Research, the CBS (Statistic Netherlands) has adjusted its report on the fall in numbers of several animal species in the North Sea.

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At the end of October, the CBS (Statistics Netherlands) reported that the number of animals in the North Sea had gone down by 30 percent as a result of bottom trawling. The statements are based on the Living Planet Report published by the CBS together with the Worldwide Fund for Nature WWF, which is partially based on data from Wageningen Marine Research. Wageningen Marine Research reacted with astonishment because the report’s conclusions cannot be drawn from the Wageningen data.

‘We have no doubt that bottom trawling has an impact on seabed life, but the intensity of fishing has actually gone down over this period,’ says Ingrid Tulp, a researcher at Wageningen Marine Research. She also thinks it is odd that a causal relationship is asserted on the basis of data collected for monitoring purposes. These data do not provide a basis for identifying causes, says Tulp. ‘You need much more searching research for that, in which you try to work out the reasons for particular population fluctuations per species or group of species. It seems as though the writers of this report arbitrarily decided on a cause. There have been other changes in the system too, such as sand replenishment and the water temperature.’

The CBS, the WWF and Wageningen Marine Research will confer about the contents and conclusions of the report, says Tammo Bult, director of Wageningen Marine Research. The CBS looks forward to the consultations, says CBS spokesperson Cor Pierik. He wants to wait until after the consultations before making a more detailed statement. The news bulletin on the CBS website has already been adjusted, to the satisfaction of Tulp. ‘We place a high value on careful formulation of conclusions and are open to consultations with the CBS.’

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