The preferences of fish and fishers

“Fisheries and offshore wind are no fruitful combination”, says Tobias van Kooten of Wageningen Marine Research. “Of course there are exceptions to the rule: certain forms of fishing could take place in wind farms, for instance with fixed gillnets or fishing lines. But the famous Dutch trawler fisheries, with nets that are dragged across the seafloor, are simply not compatible with wind farms.”

Wind turbines are positioned too close to each other to allow for trawl fisheries in between, and there are too many cables in the ground, explains Van Kooten. The concrete blocks that protect the turbines from currents would damage the nets. Moreover, wind farm owners aim to reduce risks and ensure that maintenance boats can do their work undisturbed. “But what will happen to the fish stocks and to the fishers if such large areas are closed off for fisheries? That’s an important question we are trying to answer.”

Preferences

The difficulty, as the researcher explains, is that the North Sea is not simply a homogeneous body of water. “The fish prefer certain places, depending on things like ocean currents, temperature and sediment conditions”, he says. “They choose specific areas to forage for food, and others to lay their eggs. They have different needs at every stage of their life cycle.”

In addition, different species have different preferences. Flatfish want to burrow, sea bass prefer hard structures to hunt. “All these factors make it difficult to interpret the distribution of fish”, says Van Kooten. “If there is a sudden increase in fish abundance in a certain place, does that mean that the number of fish has increased? Or that they just prefer to be in that location at that moment? This is very difficult to study.”

Scale-up

Another question is how fishers will respond to changes. “Suppose you close off certain areas, while total catch limits remain the same”, says Van Kooten. “Where do fishers go then, and what does that mean for the fish stocks? Perhaps the fishers will move to new areas that were previously little disturbed. Or they will fish larger areas more intensively, possibly with more seabed disturbance and more bycatch. So it remains to be seen what the net effect of a closure will be.”

Elsewhere in the world, such issues have already been studied, for example in protected waters around tropical coral reefs. But those results cannot simply be translated to the Dutch situation, Van Kooten emphasises. After all, there are major differences in factors such as temperature, water depth and seabed composition, but also in fish diversity and abundance and the economic situation. “On the other hand, in the Netherlands we already know quite a lot about the behavior of fish in relation to local conditions, and about fishers’ responses to this”, he says. “But the crucial question is what will happen if you scale up to the entire North Sea. That’s what we’re trying to do now.”

Changing circumstances

To this end, Van Kooten and his colleagues are developing computer models based on ecological knowledge. There is also a socio-economic component to their research. “We ask fishers about the rationale behind their choices”, explains the researcher. “How do they decide where to go and when to change course? In addition, we also receive data from ship transponders, which record the routes, and from the daily catch logs. This allows us to analyse what fishers catch where.”

Based on all these data, the researchers create a model that aims to explain what fishers do under certain circumstances. The model also makes predictions. “However, such a data-driven model only works for the situation for which it was made”, Van Kooten nuances. “If circumstances change, for instance due to changing fuel prices, fish prices or quotas, or due to climate change, the situation can change again.”

Societal question

In other words, the work is never finished, as Van Kooten concludes. “We want to understand, explain and perhaps even predict these changes”, he says. “Suppose a fisher makes choice X under certain circumstances, what will he do if the situation changes? And then there’s always individual variation. It’s very complex, but also very fascinating.”

Van Kooten notes that people tend to easily dismiss the uncertainties and changes that fishers are facing. “The sector is increasingly being restricted. You can’t just say: just take your fisheries somewhere else. This is something that we need to think about, as a society.”

Fact-based decision-making

There is a good chance that research will eventually show that fishing pressure needs to be reduced, predicts Van Kooten. “But that doesn’t mean that we have to give up on that sector altogether”, he emphasises. “Our fishing fleet and the fish on our plate are part of our cultural heritage. We just have to ask ourselves whether we really want such a large proportion of our catches to end up as cheap frozen fish abroad.”

Perhaps we should take a different approach, suggests Van Kooten, whereby fishers can earn a good living with smaller, more sustainable catches. “We need to come up with creative solutions”, he says, “just like we see in today’s agriculture.” It is not up to researchers to direct these developments, he emphasises – nor is it to steer towards more or fewer wind farms. “Our task is to provide the best possible insight into their effects on fish and fisheries, so that both the public debate and decision-making can take place based on the facts.”