There are so many issues associated with modern fishing practices that it actually makes it difficult to justify the consumption of fish and seafood at all. Globally, the growing human population and seemingly insatiable desire for seafood coming at a great cost. Studies have shown that two-thirds of the world's fish stocks are being fished unsustainably. Many species are disappearing altogether and once thriving fisheries are collapsing.

People who reduce consumption of red meat often opt for fish and seafood as a 'healthy' alternative. The fact is that there is NO evidence implying that fish or seafood is necessary for optimal health. Omega-3 essential fatty acids can be obtained from other sources, and the believed dietary benefits of fish and seafood are questionable when their fat and cholesterol content, and often high levels of heavy metals and other contaminants, are considered.

On this page we outline the current status of fisheries around the world, cover some of the issues surrounding both commercial and recreational fishing, and discuss fish and human health.

Index to this page:
       Fisheries in crisis
       By-catch - an incredible waste
              Case study: Tuna fishing and dolphins
       The impacts of fishing on other animals
       Commercial fishing
              Purse seine nets
              Drift nets
              Longline fishing
              Bottom trawling
                     Technology opens oceans to trawling
                     Trawling destroys vital habitat
                     Recent improvements in design
              Fish Farming
       Recreational fishing
              VNPA research review
              CSIRO Port Phillip Bay Study 1999
       Fish and pain
       Fish and intelligence
       Fish and human health
              Omega-3 Essential Fatty Acids
              A lot of fat and cholesterol, and no fibre
              Bio-accumulation of toxic chemicals
                     Mercury
                     Recent research on mercury in the USA
                     PCBs (Polychlorinated Biphenyls)
              Food poisoning risk
       Recent fishing issues (news articles)
       Links of Interest
       References

Fisheries in crisis

Around the world, it is now generally acknowledged that our fisheries are in crisis. It is estimated that 90% of the world’s fisheries are overfished; more than 40% of the world's marine fishery populations are heavily to fully exploited; and 25% over-exploited, depleted or recovering.

The fundamental cause of the crisis is that the oceans' resources are considered infinite and inexhaustible. Deep water, rough water and distant water are no longer obstacles to modern fishing fleets, leaving no natural refuges for fish to escape and replenish.

In the distant past, fish, as a resource, were used at a sustainable rate and people caught only as many fish as they needed. Since the 1970s with the improvements in modern fishing technology, an increase in the number of people fishing, and an increase in global population, the impacts of fishing have been escalating.

Modern fishing fleets use a range of technology including aeroplanes, larger nets, radios, sea-floor maps, and video sonar to locate schools of fish. With improved technology and the introduction of purse seine nets, longline fishing, drift nets and factory trawlers, whole schools of fish are able to be caught easily.

As coastal fisheries have been depleted, developed nations, such as Canada, Japan, the USA and European countries, have improved their long-range fishing fleets to allow their ships to move further afield. Even the once less exploited oceans are now under threat of overfishing. New and previously unfamiliar deepwater species are being taken, and we are also fishing further down the food chain, with the development of pilchard, calamari and seajelly fisheries.

Closer to home, in the deep waters of the Southern Ocean, the orange roughy has also become the victim of overfishing. It was always going to be vulnerable, being a fish that grows slowly and does not breed until it reaches the age of 40 years (they live up to 150 years). This low productivity has made it impossible for orange roughy populations to recover after harvesting. In addition, their congregation around seamounts make them easy targets for trawl operations. Although Australia's orange roughy fishery only began in the 1980s, commercial fishing has reduced stocks by 80%.

Australia has also experienced declines in southern bluefin tuna, southern sharks and gemfish. Of the 100 fisheries described in Australian Fisheries Resources, published in 1993 by the Bureau of Resource Sciences and the Fisheries Research and Development Corporation, 9 were considered to be overfished, 23 fully or heavily fished, 9 underfished and 59 of unknown status.

Hi-tech fishing fleets not only catch greater numbers of commercial species of fish, but they also collect millions of tonnes of unwanted marine life each year, as well as destroy coral and other sea-floor resources.

By-catch is defined as any catch of species (fish, sharks, marine mammals, dolphins, seals, turtles, sea birds etc.) during fishery operations other than the target species.

Typical inshore catch including a still living   turtle.	Octopus surrounded by catch of fish,   molluscs and crustaceans on a commercial   prawn trawler.

By-catch has two components, the non-target species catch that is retained and the non-target species catch that is discarded. By definition, by-catch is pre-determined, while the decision to retain or discard may occur during the catching process, at some time later during the vessel trip, or, at times, on return to port. Unwanted or undersized animals culled from a catch are discarded - thrown back into the sea, dead or dying.

In the National Oceanic and Atmospheric Administration State of the Coast report (USA), it is estimated that approximately 27 million metric tons (30 million tons) of by-catch are discarded each year in the world's commercial fisheries, compared to a total of about 77 million metric tons (85 million tons) of landed catch. Much less information is available for recreational fisheries. (1)

A shrimping crew culls the by-catch. Gulf of Mexico Commercial marine fisheries in the US alone toss away up to 20 billion pounds of by-catch each year - twice the commercial and recreational catch combined.

 

Sorting catch and by-catch on a shrimpboat deck. Shrimpers tow nets that collect shrimp, and many other animals in their path. Red snapper, croaker, mackerel, sea trout, spot, drum, and other fishes - up to nine times more than the shrimp catch - are dumped overboard, already dead or dying.

In shrimp trawl fisheries off the southern United States the issue of marine turtle by-catch came to wide public attention relatively recently, largely because of the estimated 48,000 sea turtles caught annually by shrimp fishermen. The US National Marine Fisheries Service estimates that more than 11,000 of these were dying annually. Only after intense pressure from environmental groups was remedial action taken to modify trawl nets in an attempt to exclude turtles from the catch.

Case study: Tuna fishing and dolphins

One of the most notorious and long-standing by-catch issues has been in commercial tuna purse seine fisheries in the Eastern Tropical Pacific (ETP) ocean off Mexico and Central America. For unknown reasons, yellowfin tuna in the ETP commonly swim beneath herds of dolphins and other species such as whales and whale sharks as they migrate through the open oceans. Using floating nets in excess of 2,000 meters long, ETP tuna fishing fleets deliberately encircled dolphins, whales or sharks in order to catch the tuna below them.

Dolphins are unable to    escape from the nets.

Since 1959, when the US tuna fleet introduced the practice, an estimated seven million dolphins in the ETP tuna fishery perished, of which about five million were from one species - the northern offshore spotted dolphin. Because the fishing fleets were not controlled, many dolphin populations had become severely reduced by the 1970s. Today, dolphin deaths in this fishery are declining because of an international agreement to bring the fleets under control, including a regulation that all tuna purse seine boats fishing in the ETP must carry professional observers.

Much less is known about the numbers of dolphins and other animals captured and killed in the other purse seine tuna fisheries in the Pacific, Atlantic and Indian Oceans. This is because it is only in the eastern Pacific where the scientific observers are required on all commercial tuna vessels. Many populations of dolphins, sharks, whales, even endangered sea turtles could be threatened by purse seine fishing operations, but little remedial action can be taken as long as the companies of the global tuna industry are successful in keeping their impact secret.

Purse seine nets

Purse seines are long walls of netting (up to 1 km long and 300 m deep) framed with floatline and leadline. They are used to encircle entire schools of fish at or near the surface. A drawstring cable is threaded through the bottom of the net. When the cable has pulled the netting tight, enclosing the fish in a pouch, the catch is hauled on board.

The main negative impact of purse seines has been the incidental capture of dolphins, although modifications have been developed which allow dolphins to escape alive. When small pelagic (open sea) purse seines are used with attraction lights, there can be incidental by-catch of small fish, juveniles or endangered species. The increasingly used practice of encircling floating objects, including man-made fish aggregating devices (FADs), increases the capture of small sized and immature fish amassed around such devices.

Drift nets

With nearly invisible filament mesh, enormous drift nets (used in the open ocean) catch and hold fish by the gills. When strung together, large-scale drift nets can sweep almost 60 km, catching everything in their path.

During the peak years of driftnetting in the late 1980s, official estimates pointed to annual death tolls of tens of thousands of dolphins, whales and seals. Up to 750,000 seabirds, as well as millions of non-target fish and sharks were also caught and killed. At that time more than 50,000 kilometres of drift nets were being set in the Pacific Ocean each night.

Greenpeace diver freeing a sunfish      caught in Japanese driftnet

The by-catch problem was so dire that in December 1992 the United Nations banned large-scale driftnetting in international waters, prompted by widespread protest from governments and conservation groups around the world. Until then, no regulations existed to control this indiscriminate and destructive fishing technique. Smaller drift nets (<2.5 km in length) have been used since the ban.

The United States still permits drift net fishing within US waters, and at March 2007 there were over 1300 vessels fishing with drift nets in European waters.

Longline fishing

In the 1980s, longlining became an increasingly popular method of fishing, partly in response to the increasing demand for high-quality, high-value fish destined for the clientele of upmarket restaurants.

During line setting, longliners set a   single line up to 150 km long behind   the boat. Attached to it are literally   thousands of baited hooks. An   estimated one billion hooks are set   annually by the world's longline fleets.

Many nations have fishing vessels engaged in longlining, but the fisheries of particular concern are those targeting southern bluefin tuna and patagonian toothfish.

Seabirds, such as albatross, often scavenge for food behind longlining boats and try to eat the bait from the hooks as they are set behind the boat. Some birds swallow the hooks and are dragged underwater and drown. Until recently, more than 300,000 seabirds were killed this way each year. In fact, twenty-six species of seabird, including seventeen species of albatross, became in danger of extinction because of longlining.

Thousands of hooks waiting to be   baited and set astern.

Because of the large number of birds affected, commercial fishing has been identified as the most serious threat to the survival of most albatross species. In Australia, the incidental capture of seabirds on longlines is listed as a Threatening Process under the Commonwealth Endangered Species Act, and many of the seabirds, such as albatross and giant petrels, that fall victim to longlines are listed as endangered or vulnerable.

Many cheap and simple methods for reducing the number of birds caught have been, and are being, developed, and international agreements and regulations have been developed to encourage their use. But many fishing vessels still operate illegally. These Illegal, Unregulated and Unreported (IUU) vessels, are responsible for killing thousands of seabirds each year.

This haul of dead seabirds (mainly white-chinned petrels) is from one fishing trip by a single fishing vessel.

Bottom trawling

Bottom trawling and other mobile fishing gear have effects on the seabed that resemble forest clearcutting, but affect an even larger area. Trawling crushes, buries, and exposes marine animals on the seabed, destroying habitat by plowing about half the world's continental shelf - roughly 150 times the forest area clearcut - each year.
     - Elliott A. Norse, Ph.D., President, Marine Conservation Biology Institute.

Trawling usually involves dragging a large beam or heavy weights across the ocean floor. These hold the mouth of a large net open while "tickler chains" or roller gear in front of the net scour the ocean bottom, flushing out organisms hidden in the sand. The net then scoops up virtually every living thing in its path. Trawling is so efficient and effective that some biologists have compared it to forest clearfelling.

Because trawling takes place at the bottom of the sea, its effects are largely unseen, but studies have shown that it is having a huge impact on our oceans. Pictures of sea floors after trawling reveal what looks like a paved highway where there was once a thriving ecosystem. And although trawling used to be confined to shallow waters, modern gear allows fleets to drag waters up to two kilometres deep.

Australia, North West Shelf, water depth about 70 m; first photo taken in an area where        trawling has not been allowed; second photo taken in an area heavily trawled by pair-trawlers.

Bottom trawling occurs on continental shelves in all the world's oceans. Estimates are that up to 15 million square kilometres of ocean bottoms are now trawled annually. Globally, the total area trawled is 150 times the forest area that is clearfelled each year.

A large portion of the world's trawling fleet drags for shrimp, but it is also a common method to harvest scallops, clams, crabs and bottom-feeding fish.

Perhaps the most disturbing aspect of trawling is the high rate of incidental catch ("by-catch"), including undersize specimens. This method of fishing is very indiscriminate, scooping up both target and non-target species.

Technology opens oceans to trawling

In the past, trawlers fished in areas that were easy to access, avoiding rough bottoms, more remote areas and the deeper waters. With rapid advances in fishing technologies, including global positioning systems, depth sounders and fish-finding equipment, there are very few places left around the world with commercially valuable fishery resources that have not been trawled or dredged. Targeted species plus many other species caught and killed incidentally, are caught in depths and in areas previously avoided.

New, more powerful fishing equipment, such as rockhopper and streetsweeper trawls, now allow fishing even on rough bottoms, such as rocky reefs, that in the past were free of trawling. Large rollers were added along the bottom edge of the net that allowed hauling over rocky or coral-crusted areas of seabed without snagging. Consequently, bottoms with many "hangs," such as coral reefs, are pulverized or overturned during each tow of the trawl. Until recently, rough bottoms, where fish tend to congregate, had served as de facto refuges from this type of fishing. Fishers were reluctant to risk expensive gear damage, limiting the extent of trawl impacts. Now, few limits remain; trawling can occur almost anywhere.

Trawling destroys vital habitat

Trawling destroys fundamental components of habitat necessary for marine fisheries and other wildlife, eliminating the basic structures many species need to survive.

Recovery of this habitat can take decades. In the short term, trawling re-suspends plumes of sediment, clouding the water and potentially affecting critical natural processes such as photosynthesis and feeding.

The structural complexity of rocky reefs, boulders, cobbles and gravels is necessary for the survival of many marine species, including juvenile fish. Studies show that trawling reduces structural complexity and eliminates nursery habitats. A diverse habitat structure is vital to a wide variety of marine life because it provides surfaces for feeding and hiding places from predators. Natural features provide cover for commercially important species such as cod and lobster, but also for their prey which includes crabs, small crustaceans, marine worms, and sea urchins.

"It's not a sustainable practice to turn the coral to rubble, take the fish and leave," Mark Powell, director of fish conservation for the Ocean Conservancy, states.

A survey of fishermen, scientists and other experts published in May 2003 by the Marine Conservation Biology Institute found consistent agreement that bottom trawling was the most harmful commercial fishing method, with damage to the seabed judged worse than the damage to by-catch.

The report, called "Shifting Gears", online at www.mcbi.org, noted that 98 percent of marine species lived in, on or just above the sea floor, and are therefore vulnerable to trawling.

According to Dr Sylvia Earle, renowned marine scientist and explorer, deep-sea bottom trawling should have no place in 21st-century ocean use and management. "Bottom trawling is simply not sustainable," she said "The trawl nets are stripping the seabed of life, trashing ancient corals and destroying entire ecosystems. There is much that we are still to learn about life in the oceans. Sadly, much of it will be gone before we get the chance if we don't act now."

Recent improvements in design

Until recently, every innovation was aimed at catching more fish, with little regard for the ecological consequences. That began to change after biologists started tallying the loss of seabed ecosystems crushed by repeated towing and the vast unintended toll of sea turtles and unwanted fish swept into the gaping bags.

Fishermen, too, began to recognise that in capturing fish of all sizes they were undermining the health of the resource.

Since then, under tightening laws, fleets in North American and European waters have begun to shift to designs and practices that curb the by-catch and ecological effects.

For a number of years now the United States has required that trawled shrimp, whether imported or caught in American waters, must only come from nets equipped with special grates called turtle exclusion devices that let shrimp in but divert sea turtles. American shrimp fleets are also increasingly installing grates and escape holes that cut the unwanted fish harvest in shrimp nets.

But it is clear from history and the continuing spread of technology that trawling will be around as long as humans continue to harvest fish in the wild. Improvements in design may reduce ecological damage but will never prevent it entirely.

For that reason, Dr. Callum Roberts, a fisheries scientist at the University of York in Britain, recently urged in a report to the European Union that the only way to continue to trawl and still have something worthwhile catching was to put substantial parts of the oceans off limits.

"Yes, we should have the underwater equivalent of intensive agriculture - the muddy seabed plowed by trawls," Dr. Roberts wrote. "But give us wilderness, too, the nature reserves and national parks." Without them, he concluded, "the seas will become a sorry shadow of their former abundance and the giants that we once hauled from them creatures of imagination alone."

Fish Farming

Fish farming was developed to help alleviate the depletion of wild marine life from overfishing. While aquaculture may be an option for the rearing of some species of fish, there are inherent problems:

Fish farms pollute

Some fish farms raise fish in floating net-pens -- basically, the marine equivalent of 'factory farms'. The intense accumulation of fish wastes and uneaten feed from these operations can spoil the local marine environment and spread disease to wild fish stocks. The wastes also generate bacteria that consume oxygen vital to shellfish and other bottom-dwelling sea creatures.

In addition to natural wastes, there are also antibiotics (more are given to farmed fish than any other livestock by weight) and other drugs that can harm nearshore ecosystems. Antibiotics have created resistant strains of disease that infect both wild and farmed fish. Pesticides given to the fish (e.g. to control sea lice) and toxic copper sulfate used to keep nets free of algae also build up in sea-floor sediments. Daniel Pauly, Professor of Fisheries at the University of British Columbia in Vancouver says "They're like floating pig farms… They consume a tremendous amount of highly concentrated protein pellets and they make a terrific mess."

Farmed fish are not healthy

As well as harming marine ecosystems, the antibiotics, drugs and other chemicals used in fish farming can compromise human health.

In the wild, salmon get a rich, pink hue by absorbing carotenoid from the pink krill they eat, while farmed fish are given a synthetic pigment called canthaxanthin in their feed. Without it, their flesh would be an unappetising, pale grey.

The pharmaceutical company that distributes its trademarked SalmoFan pigment has swatches similar to paint stores, so fish farmers can choose among various shades. European authorities are suspicious of canthaxanthin, which was linked to retinal damage in people when taken as a sunless tanning pill.

Scientists in the United States are far more concerned about two preliminary studies, one in British Columbia and one in Great Britain, that showed farmed salmon accumulate more cancer-causing PCBs and toxic dioxins than wild salmon. The cause appears to be the salmon feed, which contains higher concentrations of fish oil - extracted from sardines, anchovies and other ground-up fish - than wild salmon normally consume. Environmental pollutants, including PCBs and dioxins, make their way into the ocean and are absorbed by marine life. The pollutants accumulate in fat that is distilled into the concentrated fish oil.

Farmed fish aren't cheap

	The price per kilogram may seem cheaper, but globally speaking, farmed fish is anything but cheap. The fact is farmed fish represent an overall net loss of protein. According to Rosamond Naylor, an agricultural economist at Stanford's Center for Environmental Science and Policy, it takes about 2.4 kilograms of wild fish to produce one kilogram of farmed salmon.
Feeding ocean trout at a farm in Macquarie    Harbour, Tasmania.

"We are not taking strain off wild fisheries. We are adding to it," Naylor says. "This cannot be sustained forever." Factor in the energy expended to catch, process and transport that fishmeal, and "cheap" farmed fish suddenly seem absurdly costly.

Farmed fish can escape

When net pens are damaged (e.g. by storms or seals) there can be large releases of farmed fish. Some species of farmed fish do not naturally occur in the area in which they are farmed, and escapees pose a problem as they may ultimately compete with and displace precarious native stocks. Biologists fear these invaders will out-compete the native stocks, hastening their demise.

Fish farms spread disease

Disease and parasites, which would normally exist in relatively low levels in fish scattered around the oceans, can run rampant in densely packed fish farms. Clouds of sea lice, incubated by captive fish on farms, can swarm wild salmon as they swim past on their migration to the ocean.

Alexandra Morton, an independent biologist and critic of salmon farms, began examining sea lice in 2001 when a fishermen brought her two baby pink salmon covered with them. Collecting more than 700 baby pink salmon around farms she found that 78% were covered with a fatal load of sea lice, which burrow into fish and feed on skin, mucous and blood. Juvenile salmon she netted farther from the farms were largely lice-free.

Canadian commercial fishermen, initially supportive of salmon farms, have grown increasingly hostile. They were stunned last August when their nets came up nearly empty during the first day of the wild pink salmon season in the Broughton Archipelago at the northeast end of Vancouver Island. "There should have been millions of pinks, but there were fewer than anyone can remember," said Calvin Siider, a salmon gill-netter. "We can't prove that sea lice caused it. But common sense tells you something, if they are covered by sea lice as babies, and they don't come back as adults."

Salmon farmers point out that the sea lice exist in the wild. Their captive fish are unlikely hosts, they say, because at the first sign of an outbreak, they add the pesticide emamectin benzoate to the feed.

Another recent problem has been hematopoietic necrosis, an infectious virus that attacks the kidneys and spleen of fish. More than a dozen farms in British Columbia have been stricken. Jeanine Siemens, manager of a stolt farm, says, "It was really hard for me and the crew" to oversee the killing of 900,000 young salmon last August because of a viral outbreak. "We had a boat pumping dead fish every day," she said. "It took a couple of weeks. But it was the best decision. You are at risk of infecting other farms."

Frankenfish

It seems things will get worse before they get better. Recently, the prospect of genetically modified salmon that can grow six times faster than normal fish has heightened anxiety. Aqua Bounty Farms Inc., of Waltham, Massachusetts, is seeking US and Canadian approval to alter genes to produce a growth hormone that could take a year off the usual 2 & 1/2 to 3 years it takes to raise a market-size fish. Commercial fishermen and other critics fear that these "frankenfish" will escape and pose an even greater danger to native species than do the Atlantic salmon. "Nobody can predict just what that means for our wild salmon," Alaska Governor Tony Knowles said. "We do see it as a threat."