Royal Netherlands Institute for Sea Research
Royal Netherlands
Institute for Sea Research

Monitoring the fyke catches

In 1959, the Royal NIOZ took over the Beumkes fishing company. The director of NIOZ at the time, Jan Verweij, was of the opinion that the trap and fyke-net fishery, which for centuries had been highly important for the Netherlands, should be maintained. He also recognised an opportunity to monitor the migration of fish to and from the Wadden Sea. Given their location at 't Horntje, near the entrance to the Wadden Sea, the nets and traps were well-suited for this purpose.

Historical Fisheries, what are they good for?

Ever since I started working as a lab technician at NIOZ in 1972, and later as a research assistant, one of my tasks was to monitor the fyke catches. Up until that point, the fishing company, who had done it for decades, were still operating. The nets were operative from April to November, and the edible fish were sold at the junction on the main road. The fyke was emptied daily by the fishermen and the catch was counted and recorded. Occasionally I went to help, but it took a long time before I was acknowledged as a fully-fledged fisherman.

In the year that I started, director Jenne Zijlstra had the idea of using the fyke data to monitor variations in fish stocks, in order to detect regular patterns, a ‘hot topic’ at the time. Zijlstra hoped to find an explanation for the variations, for example, as a result of regular changes in the warm Gulf Stream. This laid the foundation for a long-term data series, which has now been running for 53 years.

My task is to ensure the quality of the fyke data. This means that the fish have been correctly identified to species level, and that the computer-entry of all data is accurately carried out. To this end, in 1983 I spent a year entering all the old data, and later checking all the entered numbers. Soon I began collecting additional data from the catch. This included length, and every Friday a number of animals were weighed and stripped of some scales and hearing stones for age determination. Nowadays stomach contents and stable isotopes are also recorded to determine the position of the fish in the food chain, thus ensuring that the catches are used as optimally as possible.

Meanwhile, the work I do with the fyke has changed. We now join the fyke fisherman as a group to empty the net. This way, every morning for a month, we can enjoy a bout of fresh air and at the same time identify and measure the catch. In good weather this is a real pleasure, you might even spot a seal or porpoise. Unfortunately, the weather can also be less appealing with rain and/or strong winds, and then it all begins to feel more like real work. Also placing the heavy trap poles in the spring yields many stiff backs. In short: it is fun work, with occasional hard grind. It is about this historical fisheries that I occasionally write a story.  From the experiences and problems with the fyke nets to strange passersby that you occasionally encounter in the nets.

Hans Witte