Why overfishing in the oceans could end in disaster | National Geographic

For many years, scientists have been sounding the alarm about the dire consequences of overfishing, as wild marine species are caught from the ocean in such huge quantities that fish stocks are no longer sustainably replenished. But world leaders have been at a standstill for two decades when it comes to trying to repair the damage done.

Marine biologists know exactly when large-scale overfishing began in the world’s seas. And they have a pretty good idea of ​​where this development will end up if it isn’t stopped in time. Below we summarize what this issue is all about, from the consequences of overfishing on biodiversity to the poor success of harm reduction measures.

What is the cause of overfishing?

The first signs of poaching appeared in the early 19th century, when whalers searching for the lucrative whale blubber – from which lamp oil was extracted – wiped out the entire whale population of Stellwagen Bank off the coast of Cape Cod. Many commercial fish species, including the cod, herring, and sardines caught off the California coast, had disappeared by the mid-1800s due to overfishing. These isolated localized excisions disrupted the entire marine food chain, which had been severely disrupted in the late twentieth century.

In the mid-20th century, countries around the world worked hard to expand their fishing industry to ensure a safe and affordable supply of protein-rich food for their populations. With the help of preferential policies, loans and grants, large industrial fishing fleets sprang up all over the world, and soon they were able to catch far more fish and seafood than the traditional local fishermen.

Using increasingly sophisticated methods and techniques, massive fishing fleets roamed the world’s oceans to locate, catch, and ship commercial fish species. Consumers quickly got used to the availability of a large selection of fish at reasonable prices.

But in 1989, when about 90 million tons of fish were taken from the world’s oceans each year, the industry reached its peak; Since then, catches have declined or stagnated, and fisheries for more sought-after species such as emperor bass and bluefin tuna have collapsed due to a lack of fish. In 2003, a scientific report estimated that the number of large fish species in the ocean had fallen to only 10 percent of pre-industrial levels as a result of overfishing.

Read also: The world’s seas are fishing empty despite international promises

Overfishing and biodiversity

In the face of the collapse of large fish species populations, commercial fishing fleets began to move far into the ocean, targeting smaller and smaller species. This “fishes down the food chain” (“the hunt‘) a chain reaction that seriously disrupts the ancient but fragile equilibrium in the vital systems of the world’s oceans.

For example, coral reefs in particular appear to be very vulnerable to overfishing. The balance in these ecosystems is maintained by herbivorous fish that eat algae, keeping coral reefs clean and healthy and thus promoting their growth. When too many herbivorous fish species are caught in coral reefs, either intentionally or as bycatch, the ecosystem of these reefs is weakened and they become more vulnerable to the spells of extreme weather and the effects of climate change. Also, the fragile corals that form the basis of the reef can be physically destroyed by fishing gear and waste from fishing fleets.

Overfishing also harms marine species other than fish. Trawling, a technique of fishing that involves pulling giant funnel-shaped trawls behind boats, catches not only bluefin tuna and shrimp, but also a myriad of other sea creatures in the fishing vessel’s path. Sea turtles, dolphins, seabirds, sharks, and other animals are all threatened by bycatch from trawling.

Steps against poaching

As fishing fleets have brought in smaller and smaller catches over the years, individual nations are beginning to realize that the world’s seas are not infinitely large and contain infinite amounts of fish, but are actually very fragile. In 2006 a study in the journal Science He grimly predicted that all commercial fish stocks in the world’s seas would have collapsed by 2048 if the rate of overfishing had remained unchanged.

Many scientists believe that ambitious quotas and extensive enforcement of fishing bans could bring back countless numbers of fish. The increase in the number of fish farms can also contribute to this recovery. And in many areas, there is cause for hope.

In its annual report for 2020, the Food and Agriculture Organization of the United Nations (FAO) – which sets international rules for the management of fish stocks – noted that the percentage of fish stocks that produce sustainably large amounts of fish (the ultimate goal of fisheries management), has increased slightly.

However, there are still many obstacles to overcome. About a third of the world’s fish stocks are overfished, and the percentage of the fish population that is sustainably caught continues to decline each year. The FAO report notes that this decline is particularly marked “in places where fisheries management is lacking or where it is inadequate”. Among the marine areas monitored by FAO, the Mediterranean and Black Seas had the highest proportion of fish populations (62.5 percent) unsustainably fished.

Read also: Fisheries threaten forests that keep fish alive.

Can we stop poaching?

A major obstacle to halting this destructive trend is generous government support for the fishing industry. An international survey showed that in 2018, $22 billion was spent worldwide on so-called perverse subsidies, that is, subsidies that encourage overfishing. This represents a six percent increase compared to 2009.

Posted at the time National Geographic Malicious subsidy practices are funded and would not be profitable without that assistance. For example, fuel costs for fishing vessel fleets are heavily subsidized. And in the past decade, China has increased its perverse subsidies by 105%.

Member countries of the World Trade Organization (WTO) have been negotiating since 2001 how to phase out these subsidies, without much success. And despite commitments by UN member states to reach an agreement by 2020, that deadline has passed without a decision being reached.

In 2021, the Director-General of the World Trade Organization, Ngozi Okonjo-Iweala, called on the member states of his organization to reach an agreement. “Failure to do so would be at the expense of the ocean’s biodiversity and the sustainability of the fish stocks on which many depend for their food and livelihoods.”

It is unclear whether countries will actually have the political will to find a solution, but scientists have no doubt that the WTO agreement is one of the measures that will be necessary to save the world’s seas.

Editor’s note: This article originally appeared on April 27, 2010 and has been updated.

This article was originally published in English on nationalgeographic.nl

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