Many people who eat fish and seafood believe that doing so is healthy. According to an August 1997 survey of 10,000 households in the US, commissioned by the National Fisheries Institute, more than half the respondents cited health benefits among their top reasons for eating fish and seafood. More than three-quarters believed consuming fish to be healthier than eating beef, pork or poultry. And most believed the quality of the seafood they had eaten was good. But the widely held public perception of seafood as health food is simply one whopper of a fish story!

The facts:

Omega-3 Essential Fatty Acids

There is no question that Omega-3 fatty acids are important in the human diet, and no-one disputes that they are found in fish oils, mainly those from cold water fatty fish. Many people are not aware, however, that flaxseed (linseed) oil contains nearly twice as much Omega-3, contains no cholesterol, is lower in saturated fat, and does not contain the often high levels of toxic chemicals, such as mercury, that can bio-accumulate in fish. A study published in the November 2002 issue of the New England Journal of Medicine showed mercury levels to be directly associated with the risk of myocardial infarction (heart attack) and that high mercury content may diminish the cardioprotective effects of Omega 3 fatty acids found in fish. (9) So in actual fact, flaxseed is a preferable source of Omega 3, particularly for people trying to reduce their cholesterol intake. (For more information refer to our nutritional article on Omega-3 fatty acids.)

A lot of fat and cholesterol, and no fibre

Fish and seafood generally contain excessive amounts of fat and cholesterol, with no fibre. Many people say they eat fish rather than beef in hopes of limiting fat and cholesterol. However, many fish, such as shark, catfish, swordfish, and sea trout, contain almost one-third fat, while salmon and orange roughy contain over 50%. Regarding cholesterol, prawns have double that of beef, and a three ounce serving of salmon, for example, contains 74 milligrams of cholesterol, about the same as in a comparable serving of T-bone steak or chicken.

Fish also contains significant amounts of protein, which may be okay if your diet is low in protein, but the average person on a Western diet already consumes roughly twice as much protein as is recommended. Excess dietary protein is not a risk-free indulgence; it has been linked to obesity, kidney disease and osteoporosis.

Bio-accumulation of toxic chemicals

Think about where fish and shellfish live. Everything from human waste to industrial waste ends up in our rivers, lakes, and oceans. Consequently, fish and shellfish can accumulate extremely high levels of toxins and chemical residues in their flesh due to "bio-accumulation". Big fish eat little fish and the bigger the fish (e.g. tuna and salmon), the longer the food chain, and the greater the bio-accumulation. Concentrations of toxins can be as high as nine million times those found in the waters in which fish and shellfish live. Shellfish also contain high levels of toxins because of their filter-feeding habits.

Fish may be loaded with mercury, lead, and industrial pollutants like PCBs (Poly-Chlorinated Biphenyls), DDT and dioxins. These chemicals have been linked to kidney damage, cancers, nervous disorders, impaired mental development, foetal damage, and many other health problems. And when nursing mothers eat fish, not only do they expose themselves to these contaminants, they also pass half of the toxins that they consume along to their babies.

These days, it is very difficult to find a piece of fish that hasn't been exposed to some contamination.

Mercury

Mercury is a naturally occurring element that makes its way into the environment from power generation and through industrial pollution. Rain washes it into waterways, where it settles and is eaten by microorganisms, which are in turn eaten by fish.

In the US, mercury levels in the environment have been increasing at a rate of 1.5% each year since 1970. And in at least forty states, mercury contamination has reached such high levels that state officials are advising residents to limit their consumption of fish from their entire state, or from one or more bodies of water within their state.

Mercury is very hazardous for humans and eating fish contaminated with mercury can result in serious health problems, including heart disease and damage to the brain and nervous system. This is of particular concern to growing children and pregnant women. Complicating this issue is that scientists are not certain how much mercury-tainted fish is needed to trigger health problems.

A recent report by the Research Institute of Public Health in Finland shows a significant increase of heart disease in men with elevated mercury levels. (9) Since seafood in the diet is the main source of human mercury exposure, men eating swordfish, shark, and tuna high in mercury may unknowingly be increasing their risk of an early death.

Recent research on mercury in the USA

Recent research in the US, presented by Dr Jane Hightower at a symposium of environmental health experts in Vermont, is one of the first studies to document mercury levels in Americans who eat more fish than the Environmental Protection Agency recommends.

Hightower screened 720 people from March 2000 to March 2001, then tested the mercury levels of those who reported eating more than two servings of fish a week. That's the maximum the EPA recommends for pregnant women and small children.

The tests showed that of 116 people who had their blood tested, 89% showed mercury levels greater than the 5 parts per million recognized as safe by the National Academy of Sciences. Of that group, 63 people had blood mercury levels more than twice the recommended level and 19 showed blood mercury levels four times the level considered safe. Four people had mercury levels 10 times as high as the government recommends.

About 78% of those surveyed with high mercury levels reported eating canned tuna more than three times a month; 74% ate salmon more than four times a month; and 72% said they had swordfish more than once a month. Other fish commonly eaten by respondents included halibut, ahi, sea bass and sushi.

PCBs (Polychlorinated Biphenyls)

PCBs (Polychlorinated Biphenyls), once widely used for industrial purposes but outlawed as carcinogenic in 1976, can also be found in fish due to environmental contamination. According to a six-month investigation by the Consumers Union in the US (publishers of Consumer Reports magazine), "By far the biggest source of PCBs in the human diet is fish... As PCBs linger in the environment, their composition changes, and they gradually become more toxic... And these more toxic forms are likely to be found in fish... PCBs accumulate in body tissue. The PCBs that you eat today will be with you decades into the future." (10)

Food poisoning risk

The risk of food poisoning from eating fish and seafood is far greater than that from eating beef, pork or poultry. This is because fish and the bacteria living on them flourish in the kind of temperatures found in refrigerators. Trimethylamine is the chemical that produces the 'fishy' smell we all recognise. What many people don't realise is that this odour is produced when fish begins to spoil. Fish oils decompose quickly and in the process unleash free radicals, which are linked to cell damage. Free radicals are believed to be a first important step in heart disease, cancer and the ageing process. Also, as much as 10% of raw shellfish, while appearing perfectly fresh, are infected with organisms that can cause hepatitis, salmonella poisoning or cholera.

So there is little wonder that the Center for Disease Control in the US reports an average of 325,000 food poisonings annually from contaminated seafood. In fact, this figure may severely undercount the true number of poisonings since many sufferers attribute their flu-like symptoms to something other than contaminated seafood.

With so many Americans sickened by contaminated seafood each year, the Food and Drug Administration has implemented a seafood inspection program to deal with tainted fish. The FDA's new Hazard Analysis and Critical Control Points (HACCP) plan aims to limit bacterial contamination by looking at selected points in fish processing plants, where contamination is most likely to occur. But, neither this plan nor any other will actually test whether the fish anyone buys at a store is loaded with disease-causing bacteria, mercury, or anything else. Government inspectors will not routinely use the sophisticated tests that could reveal the contaminants. One hopes that the regulations may at least prevent some food poisonings caused by the improper handling of fish and shellfish.

 

Live-Fish Market Grows, Stripping Reefs (Environmental News Network, 25 January 2007)
Amid banks of bubbling aquariums, Hong Kong resident Kerry To sat back and admired his plate-size steamed grouper plucked from one of the tanks in this Malaysian restaurant and cooked live. What he and other diners don't realize is that their appetite for live reef fish - a status symbol for many newly rich Chinese - has caused the populations of these predators to plummet around Asia as fishermen increasingly resort to cyanide and dynamite to bring in the valuable catch. Entire reef ecosystems, already endangered by pollution and global warming, are at risk.
There is also a growing live reef fish trade off the coast of California, where everything from rockfish to eels are caught and sold, mostly in Asian restaurants along the coast, according to Scot Lucas of the California Department of Fish and Game. But unlike Asia, the trade is heavily regulated and fishermen are not known to use the same destructive methods. The U.N. and the World Conservation Union released a report last year warning that human exploitation of the high seas was putting many of its resources on the verge of extinction. Reef fish are prized mostly because they are cooked live. Traders are careful to ensure they arrive that way, packaging them in bags of water and placing them in coolers for trips that often stretch for thousands of miles.

Deep-sea trawling moratorium ends up dead in the water (Mail & Guardian, 24 November 2006)
Iceland and a few other fishing nations [including Canada] have successfully undermined a three-year international effort to place a moratorium on destructive deep-sea trawling. Environmentalists say that the agreement reached at a United Nations meeting [November 23] puts the commercial interests of a few hundred trawlers from a handful of nations ahead of the international community and ignores the advice of the scientific community. "Iceland refused to endorse any measures on the unregulated high seas," said Susanna Fuller, a marine biologist with Canada's Ecology Action Centre. Australia and other nations were extremely angry at Iceland's willingness to sacrifice vital fish habitat in the high seas for its short-term fishing interests.
Scientific evidence of the need to halt unregulated deep-sea or bottom trawling is overwhelming. Trawlers literally drag a large net equipped with steel rollers weighing thousands of kilograms along the bottom of the deep sea, scooping up everything in their 100m-wide paths. Everything - including cold-water corals that have taken thousands of years to grow, endangered and unknown deep-water fish and other sea creatures - is hauled to the surface and then thrown over the side as garbage. Conservationists are calling on countries that supported the moratorium to set up a global network of marine parks and reserves. "Something has to happen in the future to protect habitat or we'll simply run out of fish," Fuller said.

Bottom Trawling Hurts Ecological Systems (Associated Press, 15 November 2006)
Fishermen who rake giant nets across the ocean floor to maximize their catch are destroying unique and unexplored ecological systems, according to a U.N. draft environmental report made public Wednesday.
Just over half of the underwater mountain and coral ecosystems in the world are located beyond national boundaries, leaving them unregulated and vulnerable to the damaging practice known as bottom trawling, the report said.
Trawlers' nets shatter coral and churn up clouds of sediment that smother sea life, the report said. The worst damage often occurs to underwater mountains that are home to thousands of species of coral and fish, some still unidentified by scientists, the report said.

World fish stocks near collapse (Ohmy News, 4 November 2006)
Action must be taken now to prevent irreversible global disaster
If you're looking for a good reason to go vegetarian, this may be it. Scientists have warned that the world's edible fish and shellfish stocks could collapse within 40 years. An international team of researchers discovered that 29 percent of fish stocks have sunk to, and even below, 10 percent of their 1950 levels. If fishing practices are not reformed all stocks will decline by 90 percent before 2048.
Report co-author Nicola Beaumont of the Plymouth Marine Laboratory (U.K.) warns: "We must take action now. If we leave this for 10 or 20 years we will reach the point of no recovery for fisheries."

World's Fish Supply Running Out, Researchers Warn (The Washington Post, 3 November 2006)
An international group of ecologists and economists warned yesterday that the world will run out of seafood by 2048 if steep declines in marine species continue at current rates, based on a four-year study of catch data and the effects of fisheries collapses.
The paper, published in the journal Science, concludes that overfishing, pollution and other environmental factors are wiping out important species around the globe, hampering the ocean's ability to produce seafood, filter nutrients and resist the spread of disease.
"We really see the end of the line now," said lead author Boris Worm, a marine biologist at Canada's Dalhousie University. "It's within our lifetime. Our children will see a world without seafood if we don't change things."

'Only 50 years left' for sea fish (BBC News, 2 November 2006)
There will be virtually nothing left to fish from the seas by the middle of the century if current trends continue, according to a major scientific study.
Stocks have collapsed in nearly one-third of sea fisheries, and the rate of decline is accelerating.
Writing in the journal Science, the international team of researchers says fishery decline is closely tied to a broader loss of marine biodiversity.
But a greater use of protected areas could safeguard existing stocks.
"The way we use the oceans is that we hope and assume there will always be another species to exploit after we've completely gone through the last one," said research leader Boris Worm, from Dalhousie University in Canada.
"What we're highlighting is there is a finite number of stocks; we have gone through one-third, and we are going to get through the rest," he told the BBC News website.
Steve Palumbi, from Stanford University in California, one of the other scientists on the project, added: "Unless we fundamentally change the way we manage all the ocean species together, as working ecosystems, then this century is the last century of wild seafood."

Report Warns of 'Global Collapse' of Fishing (New York Times, 2 November 2006)
If fishing around the world continues at its present pace, more and more species will vanish, marine ecosystems will unravel and there will be "global collapse" of all species currently fished, possibly as soon as midcentury, fisheries experts and ecologists are predicting.
The scientists, who are to report their findings on Friday in the journal Science, say it is not too late to turn the situation around. As long as marine ecosystems are still biologically diverse, they can recover quickly once overfishing and other threats are reduced, the researchers say.
But they add that there must be quick, large-scale action to protect remaining diversity, including establishment of marine reserves and "no take" zones, along with restrictions on particularly destructive fishing practices.

Illegal fishing hits tuna stocks (BBC, 5 July 2006)
East Atlantic and the Mediterranean are being stripped bare by illegal fishing, WWF has warned in a report.
Traditional tuna-trap fishermen in the Gibraltar Straits have caught 80% less fish in the last three years compared with the 1990s, the report claims. It also says that demand for tuna in the UK is being driven by "fast sushi" bars and by supermarket sales. Fleets exceed quotas and some are failing to report catches, WWF says.
The fishery is running out of control, fuelled by the unrestricted expansion of tuna farms across the Mediterranean Sea and driven by the high prices paid by traders in Japan and elsewhere. "The European Commission risks bearing witness to the collapse of this centuries-old fishery," said Dr Simon Cripps, director of WWF's global marine programme. WWF called for an immediate closure of the fishery - pending the implementation of a recovery plan and "strong" management measures.

Bottom of the Harbour: The Law of Toxic Fish (Food Legal, 15 February 2006)
On 24 January 2006, a temporary ban was placed by the New South Wales government on commercial fishing in Sydney Harbour after tests revealed high dioxin levels in fish. The ban is to remain in force for 3 months, or until further expert advice allows the ban to be lifted. Dioxins are a group of chlorinated chemicals typically emanating as a byproduct from industrial processes, such as combustion of chlorine. Dioxins can remain in the environment for a long time and will accumulate in the body fat of animals and humans, with potentially serious adverse health consequences. ...in response to the question: "Do dioxins concentrate through the food chain?": dioxins increase in concentration (bioaccumulate) as they migrate up the food chain, and humans are at the top of the food chain.

Tangled turtle dies, aged 150 (The Age newspaper, 16 January 2006)
A 150-year-old turtle that came to shore on Victoria's south coast cut and disabled by discarded fishing tackle has died.
Vets and wildlife officers tried desperately to save the two-metre-long, 350kg leatherback - an endangered species - but it died in transit, suffering cuts to its head, rope burns and necrotic, or gangrenous, muscle.
Healesville Sanctuary vet Kelly O'Sullivan said the rare male turtle came to shore near Venus Bay, south-east of Melbourne, on Saturday afternoon.
"He was entangled in discarded fishing and shark nets and he had buoys wrapped around both pectoral fins," Ms O'Sullivan said.
"He also had a long line (attached to him)."
"The injuries were severe."
She said the extent of the injuries resulted from weeks or months of entanglement.
Ms O'Sullivan said the turtle's death should highlight the dangers of discarding fishing nets, long lines and craypots in the ocean, and she urged people to pick up rubbish that could harm marine wildlife.

Protected marine areas might solve a crisis in deep-sea fisheries (The Economist, 6 January 2006)
This week sees more bad news from the Atlantic's overfished waters. It has been known for some time that deep-sea fish around the world are facing difficulties at least as severe as those experienced by their more abundant shallow-water brethren. But a paper published in this week's Nature shows that some species are in so much trouble that they may be on the brink of extinction.

Deep-sea fish in Atlantic at brink of extinction: study (CBC News, 4 January 2006)
Overfishing has driven several species of deep-water fish in the Atlantic to the brink of extinction in a single generation, Canadian biologists have found.
Populations have plummeted so rapidly that two commercially fished species, the roundnose grenadier and onion-eye grenadier, and three other species, should be classified as critically endangered – a higher rating than for the giant panda and Bengal tiger. 

Farmed salmon more contaminated than wild (NewScientist.com News Service, 8 January 2004)
Farmed salmon have significantly higher levels of toxic contaminants than salmon from the wild, US scientists have found.
Contamination by PCBs, dioxins and pesticides is on average 10 times higher in farmed salmon. The consequent health risks could detract from the known health benefits of eating oily fish, the scientists
warn.
The pollutants, widely used by industry and agriculture in the past, are now ubiquitous in fish. They accumulate in the fat of farmed salmon because the fish are fed a diet of concentrated fish oils and meal. But the salmon farming industry has always argued that the levels are too low to pose any danger.
Now that assurance is facing its first serious challenge as a result of a major investigation by environmental experts at universities in Indiana, Michigan and New York.

Farmed Salmon Loaded with Chemicals, Study Finds (Planet Ark News Story, 1 January 2004)
WASHINGTON - Farmed salmon contains far more toxic chemicals than wild salmon -- high enough to suggest that fish-eaters limit how much they eat, U.S. researchers said on Thursday.
The culprit is "salmon chow" -- the feed given to the captive fish, the researchers report in this week's issue of the journal Science.
"We think it's important for people who eat salmon to know that farmed salmon have higher levels of toxins than wild salmon from the open ocean," environmental affairs professor Ronald Hites of Albany, who led the study, said in a statement.
They looked for 13 different chemicals known to build up in the flesh of fish, including polychlorinated biphenyls or PCBs, dioxins, toxaphene, dieldrin, hexachlorobenzene, lindane, heptachlor epoxide, cis-nonachlor, trans-nonachlor, gamma-chlordane, alpha-chlordane, Mirex, endrin and DDT.
Some are pesticides, others are industrial by-products, and many are known or suspected cancer-causing agents.

Depths of despair. Trawlers accused of endangering coral, which provide habitat for Pacific fish. (San Francisco Chronicle, 11 August 2003)
Vast colonies of living coral are being found in the deep ocean off the West Coast, fragile and slow-growing habitat for sea creatures and an important hunting ground for commercial fishing.
Now, even before scientists have had a chance to survey just what's down there, conservationists say the coral is being wrecked by ocean trawlers dragging heavy equipment along the bottom.
Damaged areas might take centuries to recover.
"These are the old-growth forests of the sea," said Mark Powell, director of fish conservation for the Ocean Conservancy, the nation's largest ocean- environmental group, based in Washington, D.C. "We don't have detailed scientific knowledge of every species yet, but it's clear that a damaged coral might take at least 100 years to regenerate."

Has the Sea Given Up Its Bounty? (The New York Times, 29 July 2003)
Most of the earth's surface is covered by oceans, and their vastness and biological bounty were long thought to be immune to human influence. But no more. Scientists and marine experts say decades of industrial-scale assaults are taking a heavy toll.
More than 70 percent of commercial fish stocks are now considered fully exploited, overfished or collapsed. Sea birds and mammals are endangered. And a growing number of marine species are reaching the precariously low levels where extinction is considered a real possibility.
"It's an incipient disaster," said Richard Ellis, author of "The Empty Ocean."
A rush of recent studies, reports, books and conferences have described the situation as a crisis and urged governments and the industry to enact substantial changes.
Behind the assault, experts say, are steady advances in technology, national subsidies to fishing fleets and booming markets for seafood.
Demand is up partly because fish is considered healthier to eat than chicken and red meat.

Does Mercury Matter? Experts Debate the Big Fish Question (The New York Times, 29 July 2003)
At least all the experts agree that fish is good for you. It's high in protein, low in fat, with those terrific omega-3 fatty acids. But then, there's mercury.
Everywhere on the planet, fish are accumulating mercury in their tissues, often as the result of airborne mercury that finds its way into rivers and seas. And mercury, in all its forms, is highly toxic. In fish, it occurs in the form of methylmercury, which is known to damage neurons, particularly developing neurons. The damage seen in humans and animals at high doses is severe. Many studies - though not all - have concluded that low levels can have subtle negative effects as well if certain fish are a major part of the diet.

Study: 90% decline of big oceangoing fish (USA Today, 14 May 2003)
Commercial fishing has wiped out 90% of the world's large fish populations, according to scientists. Popular species in danger include tuna, cod, swordfish, marlin, halibut, skate, flounder and shark.
And the scientists fear the damage may be beyond repair.
The report, published today in the journal Nature, suggests international efforts to manage coastal and deep-ocean fisheries have not kept up with advances in commercial fishing and oversized fishing fleets. The study analysed 13 fisheries, sea regions that are home to large-scale fishing operations.
Most surprising to the researchers is the finding that industrialized fishing essentially has spread to every coastal and ocean source in the world. Further, industrial fishing appears to deplete fish communities within only 10 to 15 years' time.
"There's no place left in the world for fish to hide," says lead author and fisheries biologist Ransom Myers of Canada's Dalhousie University.

End of the line for fishing? (BBC News, 24 May 2002)
British deep sea fishing is in crisis. It's not a labour or territorial dispute; it's the simple lack of fish.
The EEC's fishing policy was flawed. It portrayed fishing in the same way as making steel or growing potatoes - the higher the production or total catch, the better. There was little or no planning for the future. Fish stocks were treated as limitless. Whilst scientists' warnings of diminishing stocks were largely ignored, their expertise on improving fishing techniques was eagerly grasped. Politicians were lobbied by fishing communities to keep quotas high and everyone seemed blind to the fact of impending doom for the fishing industry.

Europe's fleets 'waste Africa's fish' (BBC News, 1 April 2002)
Campaigners say European Union (EU) boats are wasting West Africa's rich fishing resources by discarding most of their catch.
Foreign boats have been fishing in Senegalese waters for more than 20 years, catching huge quantities of shrimp, tuna and now sardines. EU boats were among the first foreign vessels to obtain licences to fish off Senegal, but the situation soon became an unsustainable free-for-all, with industrial fishing destroying the country's most valuable resource. Foreign fishing methods soon began to destroy West Africa's delicate marine ecology. Brian O'Riordan, who works with a campaign group, the International Collective in Support of Fish Workers, based in Belgium, says "The ecosystem in tropical waters is very fragile, and very vulnerable to the industrial trawling techniques used by the EU. This has been described as being akin to clear-felling in a forest. They're catching everything now, the small fish, the uneconomic fish. So out of the catch they make, possibly they keep anything between 10 and 20%. But anything from 80-90% is chucked back in the water dead."

Deep fish 'trawled to oblivion' (BBC News, 18 February 2002)
Deep-sea trawlers are destroying populations of fish and other creatures in the ocean at an alarming rate, according to research presented at the American Association for the Advancement of Science annual meeting in Boston. Fishermen are now using military sonar to hunt in the deep ocean, but the slow life cycles of the species that live hundreds of metres below the surface mean their populations will collapse if they are exposed to industrial-scale exploitation. "In the deep sea, fishing gear is encountering species and habitats that are much less able to bounce back from the effects of fishing than those that live in the fast lane of the shallow seas," Dr Callum Roberts, from the University of York, UK, told the meeting.
"The pace of life in the deep sea is literally glacial. Species grow extremely slowly and they live to extraordinary ages, so, for example, the orange roughy can reach 150 years old and they don't reproduce until they are in their mid-20s to mid-30s."
Licensing fishing or introducing quota schemes to preserve stocks was unlikely to be effective, said Roberts. Marine reserves, he believes, are the only answer. "There is a worldwide scramble to exploit deep-sea fish. Forty percent of the world's trawling grounds are now waters that are deeper than the edge of the continental shelves... The early rewards from deep-sea fishing can be extremely high. The orange roughy fisheries that took off in the 1980s around seamounts in the waters off New Zealand and Australia were said to be producing catches of 60 tonnes from a 20 minute trawl. But the decline came very swiftly and today there is less than 20% of the roughy there were 10 or 15 years ago," Dr Roberts said. The impact of fishing in the deep sea goes far beyond just removing the fish. Fisheries are concentrated into places that have the greatest biological significance; places like seamounts and canyon walls where materials that are wafted in on currents support rich communities of species - corals, sponges, seafans and hydroids. Deep-sea fishing is said to be inflicting terrible collateral damage on these species as trawl meshes plough through the water.
"Off the East Coast of North America bizarre and beautiful fields of glass sponges have been trawled to oblivion. In the Southern Ocean, 'lush forests' of invertebrates have been literally stripped from the top of seamounts by trawlers targeting orange roughy."