Overfishing is a fishing practice that does not provide a sustainable state for fish populations and entails depletion of fish resources. Compared to other anthropogenic impacts on marine ecosystems, such as water pollution or climate change , overfishing is today the main reason for the massive decline in populations of many fish species, some of which are already on the verge of extinction .
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Reasons
Economic reasons for overfishing include the growing demand for seafood related to the growth of the global population . Fish is often seen as an alternative to meat food. High prices for certain types of fish often result in fishing vessel holds often reserved for the most valuable fish, while the rest of the catch is thrown into the sea as by- catch . Maintaining a large fishing fleet is often driven by government subsidies.
The technological reasons for overfishing are modern methods and techniques of fishing that have been improved in our time. Increasingly large industrial ships are able to use ever larger networks. Digital maps, satellite navigation and three-dimensional sonars allow accurate fishing even in waters with difficult underwater terrain, which previously had to be bypassed with a significant safety distance. In the open sea, modern tools find large schools of fish and make it possible to catch them completely.
Although quotas for catching certain species in many countries are partly a reasonable measure, they increase the proportion of unwanted by-catch even more, since fishermen primarily try to exhaust their quotas. In Third World countries , the situation is compounded by a lack of control and a large number of poachers who ignore any norms.
Consequences
Nowadays, there has been a significant reduction in the populations of many fish species eaten, including tuna , swordfish and others. In recent years, in the North Atlantic, commercial stocks of cod , hake , sea bass and flounder have declined by 95 percent. [one]
Often there are not enough mature individuals capable of producing a lot of caviar due to their size. Food chains are broken, which leads to a reduction in other species. Uncontrolled quotas and uncontrolled death of young individuals discarded as by-catch incurs long-term economic losses for fisheries, since the same individuals would be of increased value in the future. Huge economic losses mean the potential extinction of a particular type of fish that is being fished.
Countermeasures
There are international agreements under which catch limits are imposed on certain species. Often, these restrictions, however, are not strict enough or simply due to inadequate control. Possible technological measures include selective fishing with the help of specialized nets, which allows catching only individuals of a certain type and significantly reducing by-catch. Aquaculture is another way to protect ocean populations, but problems still exist. These include the need to independently catch numerous feeds in cases of breeding predatory fish. The use of antibiotics is also problematic, as it can have negative consequences for individuals living in the wild.
See also
- Cracking Crisis in Canada
Notes
Literature
- Charles Clover: The End of the Line: How overfishing is changing the world and what we eat. Ebury Press, London 2004, ISBN 0-09-189780-7
- Jeremy BC Jackson et al .: Historical Overfishing and the Recent Collapse of Coastal Ecosystems, Science 27. Juli 2001, Vol. 293. Nr. 5530, S. 629–637 (Review)
- Food and Agriculture Organization of the United Nations (FAO), The state of World Fisheries and Aquaculture 2006, Rome 2007 (PDF, 4 MB)