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Each fish caught in the ecosystem is a predator or loot to others. If too many tuna are caught, it will affect the food chain Every fish caught in the ecosystem is a predator or a loot to others. If too many tuna are caught, it will affect the food chain.
The report “World Ocean Review” shows the consequences of global fishing: The entire community of the oceans is under pressure. A new model could give a turn to the fishing industry.
Worldwide, a quarter of all fish stocks are overused, another 30 percent are on the threshold of overfishing. The fishery does not only put pressure on the so-called target species: if a species is decimated, it has an impact on the entire marine community.
The state of knowledge on the situation of stocks, the complex relationship between the use of fish resources and marine ecosystems and findings on illegal fishing are summarized in the second World Ocean Review (WOR 2), which was presented in Hamburg. At the same time, the report points the way to sustainable fishing.
“With the report, we not only describe the current problems of the fishery, but also provide solutions,” said Nikolaus Gelpke, managing director of the non-profit maribus GmbH, which issued the 148-page report.
Above all, the scientific content was provided by the Kiel Cluster of Excellence “Ocean of the Future”, an alliance of more than 250 researchers from several institutions working on climate change and ocean change in the Fördestadt.
“We need to understand the oceans to design scenarios for 50 or 100 years,” said Prof. Martin Visbeck from the Geomar Helmholtz Center, spokesman for the association. “The WOR gives us the chance to communicate our results in an understandable way.”
The researchers were able to show how complex the impact of fisheries can be on the marine environment, including cod: predatory fish are high on the marine food chain. If it is harvested by the ton, its prey fish, such as capelin and herring, benefit from it.
Their stocks are sometimes increasing. The species eat zooplankton. But that is also the food basis of Kabeljaularven. Thus, the increased number of prey fish increases the pressure on the cod.
The fishery even influences the evolution of individual species. This was shown by studies by Prof. Christian Möllmann from the Institute of Hydrobiology and Fishery Science at the University of Hamburg.
“By selectively catching large animals, the fish become sexually mature faster, making them even smaller and producing less offspring of lower quality,” said Möllmann. This contributes to the fact that decimated fish stocks usually do not recover so quickly.
Fishing management has only food fish in view
Such “secondary effects” of fishing have so far been disregarded, added Visbeck. “Our fishery management only looks at the food fish, but it has to keep an eye on the overall system.”
The WOR 2 is timely: at the beginning of February, the European Parliament decided on a fisheries reform that was a breakthrough for scientists and environmental organizations on their way to sustainable fishing.
But now the Council of Ministers threatens to dilute the law. For example, parliamentarians want to stop the overfishing of EU waters by 2015, and the Council considers 2020 to be sufficient.
“If we do not manage to make our fisheries more sustainable in this legislative period, then we will not be able to do it anymore, because later the stocks will be gone,” said SPD MEP Ulrike Rodust, who is negotiating with the Council for the Parliament.
“We know that you can do better, and that has to happen now,” said Möllmann. Although, thanks to stricter quotas, individual EU stocks recovered. “But many others have unhealthy age structures, and you have to give them time to increase the proportion of larger fish that multiply more.” If the stock is healthy again, the fishermen could catch more than today without overusing the resource, said the fishery biologist.
Investing in the precious resource
His colleague Martin Visbeck from Kiel goes one step further: “Today a fish only has a value when it is online, and even if the precious resource that floats in the sea gets value, you could invest in it.
Shareholders of fish stocks would have an interest in the protection of the resource, for example, to step up the fight against illegal fishing. The fish in the water has a great value, which is destroyed by an unsustainable fishery. He could pay with ten, even with 100 percent, if the withdrawal amount is right. ”
This economic approach gives the term fish market a whole new twist. For now, however, the fish trade is limited to landed goods, and that comes from all over the world.
About two-thirds of fish consumed in the EU are imported. “Stricter EU quotas can lead to more fish being imported from countries that are not as far along as we are,” said Visbeck.
But that’s even more the case for a consistent EU reform, said Visbeck: “We in Europe need sustainable fishing, only then can we demand from other countries, such as China or Russia, to fish more sustainably.”
By Angelika Hillmer