Collapsing fisheries

Posted: 25 March 2008

After decades of growth, the reported global wild fish catch peaked in 2000 at 96 million tons and fell to 93.8 million tons in 2005, the last year for which worldwide data are available. The catch per person dropped from an average of 17 kilogrammes in the late 1980s to 14 kilogrammes in 2003 - the lowest figure since 1965.

Rising populations and increasing affluence in the developing world driving the demand for fish. (Photo by I. de Borhegyi courtesy UN Food and Agriculture Organization)
Rising populations and increasing affluence in the developing world driving the demand for fish. (Photo by I. de Borhegyi courtesy UN Food and Agriculture Organization)
Rising populations and increasing affluence in the developing world driving the demand for fish. (Photo by I. de Borhegyi courtesy UN Food and Agriculture Organization)
These figures may, in fact, be too rosy according to the Earth Policy Institute. Research by Reg Watson and Daniel Pauly at the University of British Columbia reveals that over-reporting by China, the World's largest fisher, and climate-related fluctuations in Peruvian anchoveta populations may have masked the actual decline in the global catch of some 660,000 tons per year since 1988. Fish stocks. In the last 42 years, capture of wild marine fish for human consumption increased from 20 million tonnes to 84.5 million tonnes, with more than 40 per cent entering international trade. About half of the global fish stocks are fully exploited, according to the UN Food and Agriculture Organization’s 2004 State of World Fisheries report. FAO notes that some 15 per cent of stocks are overexploited, while around 10 per cent are significantly depleted. Only about one quarter of fish stocks are considered under-exploited or moderately exploited. The alarming state of capture fisheries prompted FAO to warn: “the maximum wild capture fishery potential from the world’s oceans has probably been reached and reinforces the calls for more cautious and effective fisheries management to rebuild depleted stocks and prevent the decline of those being exploited at or close to their maximum potential.”

Seven of the top 10 marine fishes - which constitues 30 per cent of the world's fish catch - have reached their limits and are classified as fully exploited or overexploited throughout their entire ranges, meaning that we cannot expect to increase their harvests. Included in this group are two types of Peruvian anchoveta, Alaska pollock, Japanese anchovy, blue whiting in the northeast Atlantic, capelin in the North Atlantic, and Atlantic herring. The other three species - chub mackerel, skipjack tuna, and largehead hairtail - are overfished in parts of their ranges.

Regions with fish stocks in greatest need of recovery include the Northeast Atlantic, the Mediterranean Sea and the Black Sea, followed by the Northwest Atlantic, the Southeast Atlantic, the Southeast Pacific and the Southern Ocean.

The tendency to catch larger and older fish first, leaving those small enough to escape from nets to breed, has over time reduced the average size of those caught. The effect on large predators is striking: for example, in the 1950s an average blue shark weighed 52 kilogrammes; in the 1990s, the average was 22 kilogrammes. In addition, fish that breed late in life are sometimes pulled out of the water before they can reproduce. When fish respond to overharvesting by reproducing at earlier ages, recent research shows that their populations are still hit hard because, for some species, the offspring of older fish have a better chance of survival than the offspring of younger fish.

Over the past 50 years, the number of large predatory fish in the oceans has dropped by a startling 90 per cent. Catches of many popular food fish such as cod, tuna, flounder, and hake have been cut in half despite a tripling in fishing effort. According to the UN Food and Agriculture Organization, the 4 million vessels scouring the world’s waters are at or exceeding the sustainable yields of three-quarters of all oceanic fisheries. Interestingly, several of these species became fishing targets only after the stocks of more desirable fish were overharvested.

Herring fishing in the Baltic Sea. © Greenpeace/NoelMatoff
Herring fishing in the Baltic Sea. © Greenpeace/NoelMatoff
Herring fishing in the Baltic Sea.© Greenpeace/NoelMatoff
There has also been a rapid decline in production in the North Atlantic Ocean; catches of many popular species, includiug cod, tuna, haddock, flounder and hake, have dropped by half within 50 years, even though fishing effort has tripled. Cod stocks in the North Sea and to Scotland's west are on the verge of collapse. Astonishingly, at least $2.5 billion of government money goes to subsidise fishing in the North Atlantic each year.

The worldwide value of Illegal, Unreported and Unregulated (IUU) catches is estimated between US$4.9-9.5 billion. Up to 30% of IUU fishing (US$ 1.2 billion) occurs beyond national jurisdiction.

Aquaculture/mariculture. With oceanic ecosystems hitting their limits and demand for fish climbing, the farming of fish, shellfish and other marine and freshwater organisms in pens and ponds supplies a growing share of the world’s food fish. Production of farmed fish and shellfish has increased dramatically over the past 15 years. In 2005, FAO reported that 47.8 million tons of fish, shellfish and seaweeds were farmed (both marine and freshwater), representing more than a doubling of farmed organisms since 1994, when 21 million tons were farmed.

China continues to account for the largest share of farmed marine and freshwater species, with 70 of the total volume and over 50 per cent of the total value. Aquaculture and mariculture are now worth $70.3 billion a year (in 2004). Worldwide, the sector has grown by an average rate of nearly 9 per cent a year since 1970. The top three producers are: China (with 30.6 million tons), India (with 2.4 million tons) and Vietnam (with 1.1 million tons).

The aquaculture industry consumes around 70 per cent of the global production of fish oil and 34 per cent of total fishmeal, much of it as pellets for salmon and trout farming. This, itself, is threatening the wild stocks of small ocean (pelagic) fish.

Nonetheless, aquaculture will alleviate pressure on wild fish only if it is done wisely. The construction of near-shore fish farms frequently requires the razing of sensitive wetlands. These farms also harbor diseases and concentrate fish wastes that can lead to harmful algal blooms and low-oxygen dead zones. Making matters worse, farmed carnivorous fish can eat several times their weight in wild fish, which only adds to pressure on such resources. Though salmon, trout, shrimp, and prawns currently account for just 9 percent of world aquacultural output, production of these carnivorous fish is doubling almost every eight years, rapidly increasing demand on wild stocks.

Better methods of fish farming include onshore mixed-species production of herbivorous fish, like carp. Fish farmers in several countries, particularly in Asia and Africa, have even had success growing fish within rice paddies, where the fish need limited or no added feed and their wastes fertilize the grain crop. Modeling future aquacultural endeavors on such lower-impact systems would be an important step toward a more sustainable fish harvest.

By-catch. Until recently, the global by-catch amounted to 20 million tons a year, approximately 25 per cent of the fish caught, a tremendous waste of potential food. Recently, FAO amended this figure downwards to no more than 8 million tons a year (as of 2004), a fact attributed to the expansion of target species and therefore a significant cut in discards.

Shrimp trawlers, which drag enormous nets over the seafloor and destroy delicate ecosystems, are the most indiscriminate; some 62 per cent of their catch is thrown back in the water. And these tallies underestimate the true losses as they only include reported bycatch and do not consider any of the marine mammals or birds that become entangled in fishing gear.

Of special concern is the impact of prawn trawlers which catch 10-20kg of marine species to obtain just 1 kg of prawns in the tropics. Prawn fishing is responsible for one-third of the world's discarded catch, despite producing less than 2 per cent of global seafood.

Longliners with thousands of hooks on central fishing lines of up to 100 kilometers (60 miles) are estimated to kill some 4.4 million sharks, sea turtles, seabirds, billfish, and marine mammals in the Pacific each year.

It is estimated that 150,000 sea turtles are killed by prawn trawlers every year. They are also thought to be the greatest threat to seahorses.

Subsidies. The irony is that governments subsidize the destruction of oceanic resources to the tune of $15-30 billion each year. In 2001, subsidies paid to the fishing industry in Japan reached $2.5 billion, equal in value to a quarter of the catch. US fishing subsidies totaled $1.2 billion, exceeding the worth of 30 per cent of the US catch. Removing these subsidies could go a long way toward relieving pressure on fish stocks.

These subsidies have helped to build a technologically advanced global fishing fleet of over 23,000 ships weighing more the 100 tons each. Overall the world's fishing fleet has the capacity to catch more than twice the fisheries' sustainable yields. But without subsidies the industry would be bankrupt.

World Trade. Fish are one of the most widely traded commodities. Seventy-five percent of the total marine harvest is sold on international markets each year, accounting for some $58 billion in exports in 2002. Japan, the United States, and the European Union are the top importers, bringing in fish caught in foreign seas or farmed in other regions and also sending industrial fishing fleets to empty the waters near developing countries. Off the west coast of Africa, for instance, large European and Japanese ships have displaced smaller boats, leaving little of the catch to feed local people.

According to the UN Food and Agriculture's 2004 State of World Fisheries, developed countries accounted for about 82 per cent of the total value of fishery product imports. Japan is the largest importer of fishery products, accounting for some 26 percent of the world total.

For many countries, and in particular for developing nations, fish trade represents a significant source of foreign currency earnings, in addition to the sector's important role in income generation, employment and food security. In a few cases, fishery exports are crucial for the economy. For example, in 2002 they represented more than half of the total value of exported commodities in Greenland, Saint Pierre and Miquelon, Maldives, the Faeroe Islands, Iceland and the Federated States of Micronesia.

Net receipts of foreign exchange by developing countries through fish trade reached US$17 billion in 2002 - a figure larger than that earned from their exports of tea, rice, coffee combined.

Human consumption. Overall, 1 billion people around the world rely on fish as their primary source of protein. While annual fish consumption per person in the industrial countries (at 29 kilograms) is more than twice that of developing countries, three quarters of the fish caught in the wild (by weight) come from developing countries, which also supply 9 out of 10 farmed fish.

According to the UN Food and Agriculture's 2004 State of World Fisheries, human consumption of fish increased from 93.6 million tonnes in 1998 to 100.7 million tonnes in 2002, providing 2.6 billion people with at least 20 per cent of their animal protein intake.

The report estimates that total world consumption of fish (food and feed) could increase to 179 million tonnes by 2015, up 47 million tonnes from 2002. Most of that new demand will have to be met by aquaculture, which could account for 39 percent of all fish production in 2015.

Sustainable fisheries. While fish stocks historically have been managed on a species-by-species basis, scientists now recognize the need for management of whole ecosystems. This includes setting aside marine reserves where fishing is prohibited altogether. There is no guarantee that a collapsed fishery can recover, but studies of protected areas around the world have shown that some exploited fish populations rebound faster and that individual fish grow larger in and around marine reserves than in unprotected areas. A global network of marine reserves protecting up to 30 per cent of the world’s oceans would cost around $13 billion—far less than the subsidies that currently promote overfishing. Such a network would also create some 1 million new jobs and bolster the number of fish that can be caught in nearby waters.

Creating sustainable fisheries also depends on strict fishing quotas and better enforcement to quash illegal fishing. Restricting the most damaging and indiscriminate types of fishing gear and adopting new bycatch-reducing technologies can stop the killing of incidental catch. For example, by modifying the shape of their hooks and switching to a different type of bait, fishers in the Western North Atlantic were able to reduce turtle bycatch by 92 per cent and increase the catch of their target species. On the other side of the globe, Australian prawn trawlers have used devices to cut bycatch by more than 60 per cent without adversely affecting their catch.

Such measures that boost the resiliency of aquatic populations and ecosystems should work in tandem with broader policies to protect our waters from looming threats like climate change and pollution. Coral reefs, kelp forests, and estuaries—the nurseries of the sea, where young fish develop and biodiversity thrives—are particularly vulnerable. Water temperatures just 1 degree Celsius above the norm can decimate coral reefs, leading to the loss of fish and other animals that depend on them. Global warming is already altering fish habitats, distribution, and migration patterns.

Informing consumers about the environmental effects of the fish they eat — whether from the sea or a farm — allows them to vote with their wallets for sustainable food choices. The Marine Stewardship Council, an independent global certification agency, has thus far certified 12 fisheries as sustainably managed, and 263 MSC-certified products are now available in 24 countries. In addition, a number of other organizations, including the Monterey Bay Aquarium and the National Audubon Society in the United States, provide information for the public and restaurateurs on the status of a variety of food fish.

Without careful management, the limits of the world’s fish supply — a resource once thought to be boundless — will become all too clear. Sustaining global fisheries and sound aquacultural practices are in the best interest of fishers and consumers today as well as for the generations to come.

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