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Fact Sheet: The Indiscriminate Slaughter at Sea Facts About Bycatch and Discards

January 12th, 1998

The Problem
Overfishing and unsustainable fishing practices have depleted fish populations and destroyed fisheries around the globe.  The UN Food and Agriculture Organisation estimates that at least 60 percent of the world's 200 most valuable marine fish species are either overfished or fished to the limit.  In the United States alone, roughly 80 percent of marine fish populations that have been evaluated are classified as fully fished or overexploited.

Many fishers are catching more fish, unwanted species, juveniles and other marine wildlife than intended.  These non-target species are known as bycatch.  The result is that every year an estimated 20 million tonnes of marine fish and other wildlife -- more than four times the entire catch of US fishers -- are killed and thrown back into the sea.  These discards represent nearly one-quarter of the world catch of about 84 million tons.

Bycatch and the resulting discards are the result of certain nonselective fishing gears and practices.  Many fishing gears and methods do not discriminate between commercially valuable fish and those that are too small to eat or sell, of limited commercial value, or illegal to keep.  Some fisheries, including those for shrimps, prawns, crabs, tunas and swordfish have particularly high rates of bycatch.

Bycatch contributes to overfishing and negatively affects marine wildlife. A particularly damaging component of bycatch is the removal of large numbers of juvenile fish.  Killing large numbers of immature fish -- before they have spawned for the first time -- is likely to reduce the future numbers of mature fish and contribute to overfishing.

Giant ocean fishes such as tunas, sharks, swordfish and marlins are especially hard hit by non-selective gears, such as driftnets and drift longlines.  For example, the population of swordfish in the north Atlantic Ocean has declined approximately 70 percent in the past two decades and continues to decline due to overfishing.  This decline is compounded by the fact that mostly juvenile swordfish are killed on longlines.  In addition, this longline fishery contributes to the demise of other large fish by unintentionally killing thousands of sharks, tunas and marlins each year.

The combined effects of indiscriminate and wasteful fishing practices threaten the long-term sustainability of marine fisheries as well as the structure and balance of marine ecosystems.

Global Consequences

  •    Sharks are killed incidentally in many fisheries.  In fact, bycatch is the number one killer of tens of millions of sharks worldwide each year.

  •    A recent study in the Southern Ocean found that more than 44,000 albatrosses are killed annually by longline vessels fishing for tuna.

  •    In 1994, the fishing fleets of the Gulf of Alaska, Bering Sea and Aleutian Islands discarded approximately 751 million pounds of fish.  The waste included 17 million pounds of halibut, 4 million pounds of herring, about 200,000 salmon, 360,000 king crabs and 15 million tanner crabs. The discarded fish could have provided about 50 million meals.

  •    While a change in fishing practices by purse seine boats targeting yellowfin tuna in the tropical Pacific Ocean has resulted in a significant decline in dolphin mortality in recent years, alternative methods used to catch tuna in the same region kill large numbers of sharks, billfish, sea turtles and juvenile tuna.

Driftnets and Drift Longlines
Large scale oceanic driftnets attracted worldwide attention in the late 1980s and early 1990s when scientists discovered that these *walls of death* entangled and drowned untold thousands of marine mammals and other wildlife each year.  In 1991, a UN resolution established a moratorium on the use of driftnets longer than 2 + km (1.5 miles). However, there have been reports of continued use of large scale driftnets.  Smaller driftnets are still legal and commonly used in fisheries around the world to catch swordfish, tuna and squid.

Longlines consist of a single-stranded fishing line up to 80 miles long and baited with as many as 3,000 hooks.  Drift longlines target large ocean fishes, primarily tunas and swordfish, but catch every creature that bites a hook.  Each year, tens of thousands of billfish, sharks, juvenile swordfish and tunas, sea turtles, seabirds and many other marine animals die on longlines.

Solutions
A portion of the unintentionally caught fish and other wildlife is sometimes useful and kept (roughly five percent worldwide); the rest is usually discarded back into the sea.  In some countries it is actually unlawful to keep non-target species.  While retaining bycatch is desirable in some cases and more complete use reduces waste, it does not lessen the enormous impact on marine life.  The answer is prevention, not retention.

The carnage can be stopped.  WWF and its coalition partners in the Ocean Wildlife Campaign are calling for:

(1)     Changes in the way fish are caught.  Fishing gear and practices should be changed or new gear and practices developed to reduce bycatch of unintentionally caught juvenile fish, sea turtles, seabirds and other marine wildlife.  Driftnets and drift longlines deserve particular attention.  Fishing gear that cannot be modified to substantially reduce bycatch should be eliminated, and more selective gears actively encouraged.

(2)     A substantial reduction in bycatch by the year 2005.  This represents an ambitious but achievable goal that can be accomplished if the individual countries and the international community commit to aggressively reduce bycatch through a combination of measures. These include:

  •    Establishing maximum bycatch standards for all fisheries, including specific bycatch reduction measures, incentives and targets   

  •    Domestic and international management measures designed to reduce encounters with non-target species and increase the survivability of what is unintentionally caught.  For example, regulations that would require fishers to use bycatch reduction devices, release live bycatch unharmed, establish closed areas for juvenile fish and other marine wildlife, and end the wasteful killing of sharks for just their fins.

WWF will be campaigning during the International Year of the Ocean to urge policy makers and responsible fishers to adopt these measures and end the indiscriminate slaughter at sea.

For more information, contact:
WWF's Endangered Seas Campaign
Branksome House
Filmer Grove
Godalming, Surrey GU7 3AB
United Kingdom
+44 1483 419294
+44 1483 427965 Fax
Nadams@wwfnet.org