Lisa Bernegger

Overfishing is when more fish is cached then the population can hold with breeding. This is not an entirely new thing, single species have been endangered in certain areas before. However, since the mid 20th century it has become a global phenomenon and now a third of all global fish stocks have collapsed. If fishing continues with current rates, a total collapse of all fish stocks mid-century is predicted. This has not only a big impact on marine wildlife, but also on the economic food security. Currently millions of people depend on fishing as their main profession and also a third of global population depends on fish as main protein source. Different policies have already been induced in certain areas, such as protecting vulnerable habitats and endangered species.  However illegal fishing is still a problem. Therefore, global action and a good monitoring system is needed.

Causes

Overfishing is when you catch more fish than the breeding capacity of the population can fill. Or simply “overfishing is a non-sustainable use of the ocean”. (Koster, 2007-2012)

Overfishing is not entirely new, in the mid 19th century, whaling increased due to a high demand of blubber and lead to the endangerment of eight whale species. (Vayas, 2020) However to expand the accessibility of protein-rich foods in the mid 20th century, there was an international governmental effort to increase global fishing capacity. This amplified the global fish and seafood consumption to the extent that in comparison to 1950, people today consume four times as much fish. (National Geographic Society, 2010) With decreasing fish-populations the fishing methods are going deeper in the ocean and farther down in the food chain. These methods also lead to the catch of a lot of bycatch. This is called “fishing down” and is leading to a chain reaction that destabilizes the oceans biological balance. (National Geographic Society, 2010) As in the last 55 years fisheries show massive drop in yields, it has become more and more clear that the ocean is not endlessly vat and rich, but rather a vulnerable and sensitive ecosystem. In the last couple years first policies have been induced in some areas, but illegal fishing and unsustainable fishing methods is still a problem in many places. (National Geographic Society, 2010)

Impacts on marine wildlife and ecology

As of 2010 estimations postulate that a third of all global fish stocks have collapsed and that three-quarters of the worlds fisheries are either collapsed, over-exploited, significantly depleted or recovering from being over-exploited. (McDermott, 2010) One  study on large ocean fish stocks in 2003  shows that these fish are declined by about 90% compared to their pre-industrial level. (National Geographic Society, 2010) This decrease of the oceans large predator fish is disrupting the oceanic food chain and with current fishing rates a possible collapse of all fish stocks mid- century is probable. (McDermott, 2010; Vayas, 2020; National Geographic Society, 2010)

A big problem with current fishing methods is the high amount of bycatch. Bottom trailing (Figure 1) is a fishing method where giant nets are run along the sea floor. Hereby the nets pick up or destroy everything in their path. This is damaging especially for fragile coral or sponge habitats. (Greenpeace, 2020)

Figure 1: Bottom or also demersal trawl fishing method. This method is used to catch for example fish near the sea floor or also prawns. From https://www.afma.gov.au/fisheries-management/methods-and-gear/trawling, last access: 20.04.2020

Another very destructive fishing method is longlining. These miles long fishing lines contain thousands of hooks and catch all kinds of creatures. Many of these unwanted bycatch species then get thrown back in the water either dead or on the verge of dying. (Greenpeace, 2020) For some fisheries bycatch can make up to 80% of the total catch. (Koster, 2007-2012) Among those discarded species (bycatch), many are also already endangered species such as turtles, albatross, manta rays or sharks and dolphins. Commercial fishing kills every year 300’000 whales and dolphins, as well as around 100 million sharks. (Greenpeace, 2020) Especially dolphins were often caught as bycatch in nets meant for tuna fishing, but nowadays these nets are produced big enough for dolphins to escape. (Vayas, 2020)

Impacts on food and economic security

Millions of people in developing coastal communities are dependent on the fishing industry for their livelihood. For approximately 15 million people fishing is the main profession and for example in India, it provides around two per cent to the gross domestic product. (The New Indian Express, 2012) To show the economic loss that arises, a study on Kenyan fishermen shows that an average catch on each trip now contains around 3kg of lobsters compared to the 1980 when this number was around 28 kg. Similar outputs can be seen in many regions and the global economic damage of this mismanagement is according to the world bank around 50 billion dollars per year. (The New Indian Express, 2012)

One example for the ecological and economical risks of overfishing can be seen in Newfoundland, Canada. The formerly successful cod fish industry came in 1992 to an abrupt full stop. No cod appeared at the start of the fishing season, after decades of overfishing and fishing mismanagement. Almost 40’000 people lost their livelihood and even fifteen years after the collapse the fisherman are still waiting for the reappearance of the cod. These communities still have not recovered from the elimination of the most important economic driver in their region. (Koster, 2007-2012)

As a third of the world’s population relies on fish as major source of protein this has also a strong impact on the worlds food security, as well as global hunger and malnutrition. (WWF, 2020)

Solutions

To have a long term sustainable and successful fishery, ensuring a healthy fish population not only for today but also for future generations, the following rules are proposed by different environmental organizations.

•  An annual catch limit

A limitation on the total number of fish that can be caught by a fishery per year. This factor should be evaluated by scientific research and should constantly be reassessed. It should be independent of short term economical impacts and politics. (Koster, 2007-2012)

• Marine protection of important habitats

Certain key parts of an ecosystem need complete protection from fisheries. For example spawning and nursing grounds of fish, corals, unique habitats or delicate sea floor should have a complete ban of fishing. (Koster, 2007-2012) This could also be complemented by a ban during specific the breeding times of fish. As an example, traditional Philippian fishing contains catching different kinds of fish during different seasons. They take the different breeding times of the different fish into account, not catching them during these times, and with that the population can remain stable. (WWF, 2020) Further a total ban on endangered species is important to guarantee sustainable fishing. (The New Indian Express, 2012)

• Improvement of the fishing practices

This is important to control the amount of bycatch. The chosen management and fishing techniques should focus on eliminating the unintentional killing and disposal of oceanic life that is not  the target catch.  (Koster, 2007-2012; WWF, 2020)

• Monitoring and Enforcement

To end illegal fishing and to ensure the fisherman do not catch more then allowed or fish in areas/ times not permitted a monitoring system is needed. It should also be uneconomic for them to cheat, for example with a solid monetary enforcement. (Koster, 2007-2012; WWF, 2020)

• Decrease of fish consumption

The decrease of global fish consumption is an option to some extent. This is more suitable for developed countries. As of now in developing countries, a lot of people are still dependent on the consumption of fish for a protein source and as a their livelihood. (WWF, 2020)

Overfishing is one part of many issues (climate change, pollution, habitat destruction and acidification) that critically endanger the ocean system. However  in comparison to these other problems overfishing is easier to handle, it just needs enforced discipline on fishing. With the right policies and actions there is still hope that most fish populations can be restored. (National Geographic Society, 2010; The New Indian Express, 2012)

References

Greenpeace (2020), “Overfishing & Destructive Fishing”, from https://www.greenpeace.org/usa/oceans/issues/overfishing-destructive-fishing/, last access: 20.04.2020

Koster P. (2007-2012), “Overfishing- A global disaster”, from http://overfishing.org, last access: 20.04.2020

McDermott M. (2010), “How Bad Is Overfishing & What Can We Do To Stop It?” treehugger, from https://www.treehugger.com/green-food/how-bad-is-overfishing-what-can-we-do-to-stop-it.html, last access: 20.04.2020

National Geographic Society (2010), “Overfishing”, from https://www.nationalgeographic.com/environment/oceans/critical-issues-overfishing/, last access: 20.04.2020

The New Indian Express (2012), “End overfishing to save country’s marine wealth”, from https://www.newindianexpress.com/opinions/editorials/2012/jun/11/end-overfishing-to-save-countrys-marine-wealth-376000.html, last access: 20.04.2020

Vyas K. (2020), “Overfishing: Can We Ever Reverse the Damage We’ve Done”, Interesting engineering, from https://interestingengineering.com/overfishing-can-we-ever-reverse-the-damage-weve-done, last access: 20.04.2020

World Wildlife Fund (WWF) (2020), “Overfishing”, from https://www.worldwildlife.org/threats/overfishing, last access: 20.04.2020