What does overfishing mean?
Fish cannot be counted like elephants in a national park. Fishery
biologists therefore have to calculate the size of a stock based on
specific parameters. The size of the annual catch is important. If
this declines it could be a sign that the stock size is shrinking. The
quantity of sexually mature adult fish, the spawners, is also important because they determine how many offspring are produced.
After all, a stock can only sustain itself if the new offspring can
compensate for the number of fish that are caught or die of
natural causes. Fishery biologists commonly assign stocks to one
of several categories: moderately exploited, fully exploited, overexploited, depleted, or recovering.
The transitions between these status classes, however, are not
sharp, for example, the boundary between a fully exploited and
overexploited stock. One reason for this is that different fish species react very differently to fishing pressure. Species that multiply
in large numbers and reach sexual maturity early can react better
to high catch volumes than species that produce fewer offspring
and require several years before they can spawn.
But basically a stock is considered to be fully exploited when it
is fished to the maximum and an increase in the catch is not possible. If the fishing is intensified at this point, the stock is then
pushed into the overexploited status. This stock then continues to
decline because there are not enough offspring being produced.
The stock is considered to be depleted when the catch is significantly below the historically expected amounts. Many researchers
define this situation as the point when only 10 per cent of the
highest historical catch is achieved. When a stock is depleted the
catch cannot be increased even with intensified fishing, which is
referred to as an increase in fishing effort.
A stock is considered to be recovering when the catch begins
to rise again after depletion. An example of this is the North Atlantic cod, whose stocks collapsed in the 1960s and recovered again
after a fishing ban. The Food and Agriculture Organization of the
United Nations (FAO) presently uses three categories to describe
the status of the stocks: non-fully exploited, fully exploited, and
overexploited.
Fishing is one of the most significant drivers of declines in ocean wildlife populations. Catching fish is not inherently bad for the ocean, except for when vessels catch fish faster than stocks can replenish, something called overfishing.
The number of overfished stocks globally has tripled in half a century and today fully one-third of the world's assessed fisheries are currently pushed beyond their biological limits, according to the Food and Agriculture Organization of the United Nations. Overfishing is closely tied to bycatch—the capture of unwanted sea life while fishing for a different species. This, too, is a serious marine threat that causes the needless loss of billions of fish, along with hundreds of thousands of sea turtles and cetaceans.
The damage done by overfishing goes beyond the marine environment. Billions of people rely on fish for protein, and fishing is the principal livelihood for millions of people around the world.
Many people who make a living catching, selling, and buying fish are working to improve how the world manages and conserves ocean resources. WWF works with a cross-section of stakeholders to reform fisheries management globally, focusing on sustainable practices that not only conserve ecosystems, but also sustain livelihoods and ensure food security.
Fish cannot be counted like elephants in a national park. Fishery
biologists therefore have to calculate the size of a stock based on
specific parameters. The size of the annual catch is important. If
this declines it could be a sign that the stock size is shrinking. The
quantity of sexually mature adult fish, the spawners, is also important because they determine how many offspring are produced.
After all, a stock can only sustain itself if the new offspring can
compensate for the number of fish that are caught or die of
natural causes. Fishery biologists commonly assign stocks to one
of several categories: moderately exploited, fully exploited, overexploited, depleted, or recovering.
The transitions between these status classes, however, are not
sharp, for example, the boundary between a fully exploited and
overexploited stock. One reason for this is that different fish species react very differently to fishing pressure. Species that multiply
in large numbers and reach sexual maturity early can react better
to high catch volumes than species that produce fewer offspring
and require several years before they can spawn.
But basically a stock is considered to be fully exploited when it
is fished to the maximum and an increase in the catch is not possible. If the fishing is intensified at this point, the stock is then
pushed into the overexploited status. This stock then continues to
decline because there are not enough offspring being produced.
The stock is considered to be depleted when the catch is significantly below the historically expected amounts. Many researchers
define this situation as the point when only 10 per cent of the
highest historical catch is achieved. When a stock is depleted the
catch cannot be increased even with intensified fishing, which is
referred to as an increase in fishing effort.
A stock is considered to be recovering when the catch begins
to rise again after depletion. An example of this is the North Atlantic cod, whose stocks collapsed in the 1960s and recovered again
after a fishing ban. The Food and Agriculture Organization of the
United Nations (FAO) presently uses three categories to describe
the status of the stocks: non-fully exploited, fully exploited, and
overexploited.
Fishing is one of the most significant drivers of declines in ocean wildlife populations. Catching fish is not inherently bad for the ocean, except for when vessels catch fish faster than stocks can replenish, something called overfishing.
The number of overfished stocks globally has tripled in half a century and today fully one-third of the world's assessed fisheries are currently pushed beyond their biological limits, according to the Food and Agriculture Organization of the United Nations. Overfishing is closely tied to bycatch—the capture of unwanted sea life while fishing for a different species. This, too, is a serious marine threat that causes the needless loss of billions of fish, along with hundreds of thousands of sea turtles and cetaceans.
The damage done by overfishing goes beyond the marine environment. Billions of people rely on fish for protein, and fishing is the principal livelihood for millions of people around the world.
Many people who make a living catching, selling, and buying fish are working to improve how the world manages and conserves ocean resources. WWF works with a cross-section of stakeholders to reform fisheries management globally, focusing on sustainable practices that not only conserve ecosystems, but also sustain livelihoods and ensure food security.
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