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Understanding fishers and the choices they make

Wind farms and oil and gas rigs are making the North Sea an increasingly crowded place. There are also a number of very busy shipping routes. This is reducing the space available to fishers. How will they be able to extract enough food from the sea? To answer this question, marine ecologists and social scientists at Wageningen Marine Research are closely studying the conduct of fishers.

The North Sea is a patchwork of navigable waters and conservation areas. Wherever wind turbines are constructed, fishing is off limits, because the nets damage the power cables. “The question therefore is how fishers can extract enough herring, sole or cod from the waters, and how we can ensure that everyone is able to make good use of the North Sea,” says marine ecologist Karen van de Wolfshaar. “Policy makers, businesses and fishers can expect to get a clearer answer to this question thanks to the agent-based models being developed by Wageningen University & Research.”

Family business

The modellers are working on a computer model to better understand the conduct of fishers, particularly in terms of sharing information. Van de Wolfshaar points to family-owned businesses as an example. For generations, fishers have passed down to successors and family members their knowledge of the best fishing grounds and where to go in different seasons. That collective memory grows over time.

Van de Wolfshaar: “We want to simulate that in a model, using what we refer to as agents. Every agent represents a ship and that ship can share information about the catch with other agents. The sharing of information can be advantageous: it means an individual agent can be made aware of the expected catch in multiple locations. But that can also be a disadvantage. If others also know about those locations, they may crowd each other out in the better places. Will the number of people included in the sharing of information affect the catch? So what we’re doing is simulating the interactions of the fishers and the effect of those interactions on the fishing industry.”

What we’re doing is simulating the interactions of the fishers and the effect of those interactions on the fishing industry

Karen van de Wolfshaar

According to Van de Wolfshaar, the first step for the researchers is to take something very complicated and make it as simple as possible. “Then we keep adding an element to the model to see what impact it has on the fishing industry. So we’re decorating the Christmas tree bit by bit. As we do this, we share our knowledge of this type of model with other researchers and include their findings too. Eventually, others will be able to use our framework – a new software tool – to get a better understanding of the conduct of farmers, for example, or of a pack of wolves. Because they too share information about how to improve their yields or catches.”

Do you have a question about the conduct of fishers? Ask our expert: dr.ir. KE (Karen) van de Wolfshaar

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Mechanistic model

Karen van de Wolfshaar’s research is part of the data and modelling work being done by the Next Level Animal Sciences research programme at Wageningen University & Research. “We’re focusing on creating a mechanistic model, just like our colleagues who are modelling the energy systems of marine mammals. A mechanistic model enables us to better understand a complex system by allowing us to research the workings of the individual components and the way in which they fit together.”

Less time to cast the nets

Van de Wolfshaar gives the example of an area of the North Sea where the number of active fishers is growing because they’ve been excluded from other areas. “They need to keep an eye on each other to avoid getting into accidents. That leaves them with less time to cast their nets. Does that have an impact on the catches of individual ‘agents’ and on the fleet as a whole? Another example: we know from fieldwork and experiments that the water temperature is rising. We can identify specific sites that are no longer attractive to fish. This, too, reduces the space available for fishers to fish.”