Overfishing

People catch too many fish from the water.

This happens when we take fish faster than they can make babies.

When there are too few fish, it is hard for them to grow. Some fish might even disappear forever.

Fishing can also hurt the homes where fish live. Large nets can scrape the ocean floor.

This can hurt coral and other sea life.

Sometimes, fishers catch animals they did not mean to catch. These animals often die from their injuries.

We can help by making rules for fishing. This helps keep the ocean healthy for everyone.

Overfishing happens when we take fish from the water too fast. We take them faster than they can make new babies. This can make fish populations very small.

There are different ways this happens. Growth overfishing occurs when we catch fish before they grow big. This means we get less food in the end. Recruitment overfishing happens when there are not enough adult fish to make babies. This can cause a species to disappear. Ecosystem overfishing changes the whole balance of the sea.

Fishing can also hurt where fish live. Big nets can scrape the ocean floor. This can damage coral reefs.

Sometimes, fishers catch animals they did not want. This is called bycatch. Many of these animals die from their injuries. In shrimp fishing, the bycatch can be five times larger than the shrimp. In 2017, 34 percent of the world's marine fish stocks were overfished. We can help by making rules for fishing and using aquaculture, which is farming fish in water.

Overfishing happens when people take aquatic animals from the water too quickly. This occurs at a rate faster than the species can naturally replenish its population.

When this happens, fish populations become very small in that area. This can lead to a loss of biodiversity and change how ecosystems work. If fishing continues at an industrial scale, it can lead to critical depensation. This is a point where the population can no longer sustain itself. At this stage, a species might face extirpation or even extinction.

There are three main ways this process works. Growth overfishing happens when fish are caught before they reach an ideal size. This results in a smaller total yield than if they were allowed to grow. Recruitment overfishing occurs when there are not enough mature adults left to reproduce. Without enough adults to make offspring, the population cannot grow back.

Finally, ecosystem overfishing happens when the balance of the entire environment shifts. For example, if large predatory fish are removed, smaller species might take over. This changes the energy flow within the whole system.

History shows that intensive fishing has grown significantly since the 1950s.

In the past, fishing was concentrated in only a few areas. Now, it has spread to cover nearly all fisheries around the world. Overfishing was even seen in pre-industrial times. For instance, the western Atlantic Ocean saw heavy fishing starting during the early days of European colonization. Data from the FAO shows that the percentage of fish stocks at unsustainable levels rose from 10% in 1974 to 33.1% in 2015.

Many specific places and animals show the effects of these changes.

In the 1970s, the Peruvian anchovy fishery crashed after overfishing and an El Niño season. The catch dropped from 10.2 million metric tons in 1971 to only four million tons over the next five years. In the Great Lakes, the blue walleye became extinct in the 1980s.

Deep-sea fish like the orange roughy are also at risk because they grow very slowly. Some of these fish may not reach breeding age for 30 to 40 years. This makes it very hard for them to recover from being caught.

Overfishing also creates a problem called bycatch. This is when fishers catch animals they did not intend to take.

These unintended animals are often returned to the ocean, but they usually die from injuries. In shrimp fishing, the amount of bycatch can be five times larger than the shrimp caught. This can harm habitats like coral reefs when big nets scrape the ocean floor. To help, people use government regulations, aquaculture, or consumer awareness. These steps can help protect the food supply for millions of people.

Overfishing is the removal of aquatic animals from a body of water at a rate faster than the species can naturally replenish itself. This process involves the overexploitation of existing fish stocks. When this happens, the species becomes increasingly underpopulated in that specific area. Overfishing can occur in many environments, including ponds, rivers, lakes, and oceans. It can lead to resource depletion and lower biomass levels. If industrial-scale commercial fishing continues, it can cause critical depensation. This is a state where the population can no longer sustain itself. This often results in extirpation or even extinction.

Scientists recognize three distinct types of biological overfishing. The first is growth overfishing. This occurs when fish are harvested at an average size smaller than the size needed to produce the maximum yield per recruit. A recruit is an individual that reaches maturity or specific fishery limits. The second type is recruitment overfishing. This happens when the spawning biomass, or the mature adult population, is depleted too much. At this level, there are not enough adults to produce enough offspring to replenish the group. The third type is ecosystem overfishing. This occurs when the balance of the entire ecosystem is altered. For example, removing large predatory species can cause an increase in small forage fish.

Overfishing can also trigger a process called fishing down the food web. This occurs when all the larger fish in an area are caught. Fishermen then begin to target smaller individuals to meet demand. This process decreases fish populations and reduces genetic diversity. Lower genetic diversity makes species more susceptible to disease and less able to adapt to environmental stressors. Additionally, catching smaller fish leads to the breeding of smaller offspring. This is problematic because smaller female fish are often less fecund, meaning they produce fewer eggs. This cycle makes it much harder for the population to recover.

History shows that intensive fishing has expanded significantly since the 1950s. Before this time, fishing was mostly concentrated in a few specific areas. Now, intensive fishing has spread to encompass nearly all fisheries globally. However, significant overfishing was even observed in pre-industrial times. The western Atlantic Ocean saw heavy fishing starting during early European colonization. Data from the FAO shows a clear downward trend in sustainable fishing. In 1974, 90% of fish stocks were at biologically sustainable levels. By 2015, that number dropped to only 66.9%.

In contrast, the percentage of fish stocks at unsustainable levels has grown. In 1974, only 10% of stocks were fished at unsustainable levels. By 2015, this figure rose to 33.1%. The largest increases in these unsustainable levels occurred during the late 1970s and 1980s. Certain regions show much higher rates of overfishing than others. In 2015, the Mediterranean and Black Sea had the highest percentage of unsustainable stocks at 62.2%. The Southeast Pacific followed closely at 61.5%. The Eastern Central Pacific and Northwest Pacific had much lower proportions, ranging from 13% to 17%.

Specific examples highlight the severe consequences of these trends. In the 1970s, the Peruvian anchovy fishery crashed due to overfishing and El Niño. The catch fell from 10.2 million metric tons in 1971 to about four million tons over the next five years. This caused a major loss to the economy of Peru. Another example is the Atlantic northwest cod fishery off Newfoundland. This collapse led Canada to impose an indefinite moratorium in 1992. Deep-sea fish like the orange roughy are also at high risk. These fish grow very slowly and may not reach breeding maturity for 30 to 40 years.

Overfishing also causes significant collateral damage through bycatch. Bycatch is the accidental capture of unintended species during fishing. This represents about a quarter of all marine catch. In shrimp fishing, the mass of bycatch can be five times larger than the shrimp caught. Many of these animals die from injuries or exposure after being returned to the water. Furthermore, methods like bottom dragging can scrape the ocean floor. This destroys coral, sponges, and other slow-growing benthic species. These species provide vital habitats for commercial fish.

Addressing these issues requires various mitigation options. Governments can use regulation and the removal of subsidies to control fishing. Minimizing fishing impact and using aquaculture are also important strategies. Consumer awareness can also play a role in protecting global fish stocks. Protecting these systems is vital because overfishing threatens the food supply for millions of people. It also impacts biodiversity and the stability of entire marine ecosystems.