Unsustainable Seafood

by Maria Stevens, February 2010

Over the past half-century, ample attention has been paid to the rejuvination of sustainable food production. Grassroots movements have matured into highly organized organic certification bodies. Environmentalists and scientists have illuminated on the environmental and social externalities of intensive agricultural, meat, egg, and dairy production. What has lacked widespread public comprehension, however, is seafood. The origins of fish and marine-life remain largely esoterique, and the methods employed to capture these foods are generally poorly understood.

The average person can cite a few facts about seafood: the seas are being overfished; some fishing methods produce a lot of bycatch, which is bad; large species of fish have increasing levels of contaminants in them, like mercury; some seafood is not safe to eat more than a couple times a month; fish farming seems like a good idea, but it is sometimes environmentally unfriendly.

The substance of these claims runs far deeper than the average consumer can articulate. This article will explain the picture of the current state of affaris; types of over-fishing; types of fishing vessles; destructive fishing practices; the role of government subsides in the industry; and fish farming and its criticisms. This article will also provide definitions for sustainable seafood production, and finally, a small guide to purchasing and eating seafood which embraces an ethic represntative of compromise between conflicting considerations in the seafood industry.

Snapshop of the state of affairs:

Death of the waters:

In the past decade, a landslide of scientific evidence has come in, supporting claims that the fishing industry is contributing to global environmental collapse. Oceans are increasingly polluted by garbage, chemicals, and industrial waste. In addition to sewage, dynamite fishing, and bottom-trawling, global warming may be a cause for increasing ocean temperatures, which lead to the die-off of diverse coral reefs. The burning of fossil fuels has changed the pH levels of seas, altering carbonate and calcium levels essential to the growth of these coral reefs. Fisherman and scientists are discovering oxygen-free “dead zones” with increasing frequency; these dead zones are caused by an increase in the amount of algae, once consumed by fish populations. When algae sinks to the bottom of the ocean, it decays and releases a compound called hydrogen sulfide, which has a tendency to kill other forms of life.

Over-fishing and habitat destruction:

It is estimated that 90% of the top-level marine predators—examples include tuna, marlin, and swordfish—have alread been caught. The distict lack of these predatory species has led to a boom in lower-level species, thereby causing dramatic chain-reactions in the balance of marine ecosystems. Fishing methods such as bottom trawling (analagous to running a bulldozer accross delicate terrain) have obliterated much of the ocean’s diverse habitats for marine life. Invasive species, both plant and animal, are spreading rapidly into new areas, creating a less-diverse, inevitably weakened, homogeneous state for marine life. These phenomena are fueled by the world’s increasing demand for more marine protein, despite rapidly decreasing supplies.


Finally, pollutants from world industrial practices have been expelled into the world’s water supply in such abundace that marine life has become contaminated by scores of different chemical compounds. By living directly in these compounds, fish collect high concentrations of contaminants in their flesh, which are then easily passed on to humans. There exists a wealth of scientific evidence supporting relationships between such contaminants and adverse health effects in humans. Many larger species of fish, which eat smaller species, are deemed unsafe to eat, due to the average level of contaminants found in them.

Overfishing, vessles, destructive practices, subsidies, fish-farming and its criticisms:

There are three recognized types of overfishing: growth overfishing, recruit overfishing and ecosystem overfishing:

  • Growth overfishing is when fishes are harvested at an average size that is smaller than the size that would produce the maximum yeild per recruit, thus making the total yield less than it would be if the fish were allowed to grow to a reasonable size.
  • Recruit overfishing is when the mature adult population is depleted to a level where it no longer has the reproductive capacity to replenish itself.
  • Ecosystem overfishing is when the balance of the ecosystem is altered due to overfishing.

Fishing vessles:

According to the Food and Agriculture Organization of the United Nations, in 2004 there were four million commerical fishing vessels, with 1.3 million of them being merchendized deck vessels weighing over 1000 tons. The remaining vessels are small, undecked boats generally powered by sails or oars. Vessels are permitted to fish within 200 miles of shore, under regulation.

Commercial fishing vessels can be classified by architecture, the type of fish they catch, the fishing method used, or geographical origin. The following list is classified by type of gear used to fish:

-A trawler is a fishing vessel which uses a net trawl (trawl: a conical fishnet dragged through the water at great depths) in order to catch large volumes of fish.

Seiners are a large group ranging from open boats as small as 10 metres in length, to ocean going vessels, and use various types of sein nets (a seine is a large fishing net that hangs vertically in the water by attaching weights along the bottom).

– A long-liner is a fishing bot that uses miles of fishing lines and hooks to catch fish.

Dredgers use a dredge (any instrument used to gather or take by dragging) for collecting molluscs from the seafloor.

Gillnetters are named by the type of net employed, which catches fish by means of a snare method.

Lift netters are equipped to operate lift nets, which are held from the vessel’s side and raised and lowered by means of outriggers.

Trap setters are used to set pots or traps for catching fish, crabs, lobsters, crayfish and other similar species.

Handliners are normally undecked vessels used for handlining (fishing with a line and hook). Handliners include canoes and other small or medium sized vessels.

Destructive Fishing Practices:

Some fishing methods are more destructive than others and can cause irreversible damage to aquatic habitats and ecosystems. The majority of these practices are illegal. In cases when they are illegal, the law is seldom adequately enforced, or the penalities are so small that is provides fishermen no incentive to obey the law.

  • Explosives – Dynamite or blast fishing is cheap and easy, and uses anything from dynamite to homemade bombs. Fish are killed by the shock from the blast and are easily collected from the surface, or skimmed from the bottom. The explosions kill all forms of life indiscriminately, and also damage the natural habitats of fish, which does not promote a successful next generation.
  • Bottom trawling – Bottom trawling is trawling (towing a trawl, which is a fishing net) along the sea floor. The net kicks up a cloud of dust, through which fish cannot see the approaching net. Once within the net, fish must continue swimming at the pace of the net until they reach exhaustion. The trawl also bulldozes over everything in its path, and is the most widely cited destroyer of marine habitat.
  • Cyanide fishing employs cyanide to capture live fish near coral reefs for the aquarium and seafood market. Many fish die immediately, or in transit, from this method. Other that survive often die from shock or from massive digestive damage. The high concentrations of cyanide on reefs harvested in this fashion damages coral polyps and has also resulted in cases of cyanide poisoning among local fishermen and their families.
  • Muroami is a destructive artisan fishing method employed on coral reefs in Southeast Asia. An encircling net is used with various pounding devices, which are repeatedly lowered into the area encircled by the net. They smash the coral into small fragments in order to scare fish out of their coral refuges.

Fishing subsidies:

A subsidy is a form of financial assistance from the governement, to a business or economic sector. Subsidies are often granted to help flagging industries remain afloat. Subsidies have had a long-standing influence in sectors of the world food production system (the most common examples are amount paid for cash crops like corn).

The seafood industry, rapidly spiraling to an end due to resource exhaustion, is heavily affected by subsidies. Seafood subsidies are unique in that they blatantly contribute to the problems which led to their necessity in the first place. The seafood inustry is affected in such a way because, unlike agriculture and livestock rearing, there is nothing to grow or cultivate; fishing is still hunting, and there are no “farmers” adding inputs for the promotion of the next “crop.”

“Even as fish stocks dwindle, some of the world’s richest nations are paying billions of dollars to keep flagging fishing industries afloat through fishing subsidies. The result: a growing series of economic, social, and environmental crises around the world… Estimated at tens of billions of dollars per year, these subsidies are equivalent to roughly 20% to 25% of the value of the landed fish catch worldwide. This scale of subsidization is a huge incentive to expand fishing fleets and overfish.” -http://www.worldwildlife.org/what/globalmarkets/fishing/subsidies.html

Removal of subsidies:

The fisheries scientist Daniel Pauly and economist Ussif Rashid Sumaliaexamined subsidies paid to a specific fishing sector–bottom trawl fleets–around the world. They found that $152 million US are paid to deep-sea fisheries. Without these subsidies, global deep-sea fisheries would operate at a loss of $50 million a year. Most of the subsidies are for the fuel the fishing vessels burn travelling beyond the 200 mile limit and dragging weighted nets. Worse, fleets fishing in these international waters are not policed, and there is pracically no agreement on acceptable fishing methods; hence, fleets are often free to fish as destructively and heedlessly as they like.

  • “There is surely a better way for governments to spend money than by paying subsidies to a fleet that burns 1.1 billion litres of fuel annually to maintain paltry catches of old growth fish from highly vulnerable stocks, while destroying their habitat in the process.” – Pauly

  • “Eliminating global subsidies would render these fleets economically unviable and would relieve tremendous pressure on over-fishing and vulnerable deep-sea ecosystems.” – Sumaila

Indoor Fish Farming:

An alternative to fishing wild populations is aquaculture, or fish farming. Fish are raised in controlled environments, with numerous inputs, much in the manner that a farmer would cultivate his land.

Cages: Fish cages are placed in lakes, bayous, ponds, rivers or oceans to contain and protect fish until they can be harvested. Fish are stocked in cages, artificially fed, and harvested when they reach market size. Many types of waters can be used (rivers, lakes, filled quarries, etc.), many types of fish can be raised, and fish farming can co-exist with sport fishing and other water uses. On the other hand, there are concerns of disease, poaching, and poor water quality. There are occasional cage-failures, which lead to escapes; escapees have the potential to cause significant ecosystem alteration, depending on how non-native they are to the area. An alternative to cage farming in natural bodies of water is farming in self-contained facilities; the overhead for a system such as this, however, is astronomical, and therefore not a popular option. Because of its high capital and operating costs, this alternative is generally restricted to practices such as broodstock maturation, larval rearing, fingerling production, research animal production, and caviar and ornamental fish production.

Fry Farming: Trout and other sport fish are often raised from eggs to frys and then transported to streams and released. Normally, are raised in long, shallow, concerte tanks and receive commercial fish food in pellets. This method is can be focused on species which cannot be easily or successfully farmed to adulthood.


Despite it being an alternative to a highly self-degrading system, aquaculture is subject to a plethora of criticisms. The many drawbacks that apply to factory farming apply to fish farming.

Top-level carnivorous fish require fish-derived feed; these fish are caught in the wild, which seems counter-intuitive to a system meant to be an alternative to wild-caught seafood. There are some vegetable-derived proteins that can supplement fish diets, but there are no vegetable-derived oils being sucessfully implemented.

Secondly, farmed fish are kept in concentrations never seen in the wild. This can cause several forms of pollution. In such tight areas, fish rub against each other and the sides of their cages, damaging their fins and tails. Disease and infections spread eaily in such conditions. Fish that tend also to be animals that aggregate into large schools at high density are more successful farm breeds. Species of sea lice have become problematic. Because of parasite and infection problems, some aquaculture operators frequently use strong antibiotic drugs to keep the fish alive, as is practiced in factory farming. The residual presence of these drugs in human food products has become controversial.

The very large number of fish kept long-term in a single location contributes to habitat destruction of nearby areas. Fish in such high numbers produce a significant amount of condensed faeces, often contaminated with drugs, which again affect local waterways. Wild fish populations that swim nearby farms frequently pass pathogens, or receive them.

Defining sustainability:

The notion of sustainable development is, for many, impossible due to the view that development inevitably depletes and degrades the environment

Ray Hilborn of the University of Washinton distinguishes three ways of defining a sustainable fishery (http://en.wikipedia.org/wiki/Fishing_capacity#cite_note-Hilborn2005-0):

  • Long term constant yield is the idea that, when undisturbed, nature establishes a steady state that changes little over time. If fishing is done properly, at about the level of maximum sustainable yield, then nature will also adjust and settle down to a new steady state, with the harvest occurring sustainably in a stable and predictable way. However, this is a naive view. Such constancy is not an attribute of marine ecosystems, and this approach fails. It is entirely natural for stock abundance to fluctuate, and the potential yield of fish stocks changes with naturally occurring short and long term variations.
  • Preserving intergenerational equity acknowledges that natural fluctuations occur, and regards as unsustainable practices which would result in a deterioration of the genetic structure, or habitat loss, or depletion of stock levels to the point where it requires several generations for rebuilding. Providing the stock can be rebuild within one generation, overfishing may be economically foolish, but it is not unsustainable. This is currently a widely accepted definition.
  • Maintaining a biological, social and economic system is a perspective which considers the health of the human ecosystem as well as the marine ecosystem. A mixed-species fishery which rotates its fishing effort can deplete individual stocks and still be sustainable so long as the ecosystem retains its intrinsic integrity. Such a definition might consider as sustainable fishing practices that lead to the reduction and possible extinction of some members of the ecosystem.”

Social sustainability:

The fisheries and aquaculture sectors are, directly or indirectly, a source of livelihood for hundreds of millions of people, the majority of which live in developing countries. While it is important to protect biodiversity, people also need seafood to ensure food and economic security; these considerations complicate the problems of the seafood industry.

Environmental sustainabily (that is, protecting the environments current homeostatic condition) may not be an option. Still, the concept of social sustainability can come into play. A fishery is socially sustainable if the fishery ecosystem maintains the ability to deliver products the social system can use. In other words, even if there is a major species shift (example, an exploding jelly fish population due to a lack of predatory fish), from the social point of view, it is acceptable as long as the new species can be properly utilised (jellyfish are edible, with a protein similar to the protein found in egg whites; they are merely not popular). Humans are highly adaptable creatures, and have adjusted their ways of life according to shifts in the environment. Humans are not infallible; there are also many examples of severe environmental and species degredation that have wiped out entire civilizations in a short span of time.

How to proceed:

Stop the subsidies, or only allow subsidies that support small local fisheries.

Small-scale fisheries should not be favoured over large-scale operations ebcause of romantic notions of rugged small operators battling both the elements and anonymous corporations. [They ought to be supported] because of the scientific evidence available to confirm the common-sense inference that local fishers, if given privileged access, will tend to avoid trashing their local stocks, while foreign fishers do not have such motivation.” – Daniel Pauly

Small fisheries are input-efficient, adaptable, use less fuel, employ more people, are socially sustainable, and are less destructive to the environment.

There are, of course, numerous other measured that must be taken: governments should not set fishing quotas; rather, quotes should be set by purely independent organizations. Stricter policing and regulations must be set. Waters should be protected against exploitation by having seasons of being open and closed, similar to areas of land portioned off for hunting. There needs to be a more concerted international effort to set standards. More sustainable fishing certification bodies must be developed, in order to set a new industry standard. Eco-labels are great tools, but they are merely a beginning. There needs to be more transparency across the entire industry. Labelling standards should be high enough that every consumer can have the knowledge of where, when, and how his seafood was fished.

How to eat?

Avoid large predatory fish like tuna, shark, cod, grouper, and swordfish. All of their numbers are dwindling, and the levels of PCBs, heavy metals, and other contaminates are potentially harmful—seriously harmfull—to human health.

Avoid most farmed seafood, particularly shrimp, eel, catfish, and salmon. The conditions under which these species are raised are putrid. The amounts of ecosystem devastation, disease, and parasites are high.

Avoid any fish that was fished by destructive methods, particularly bottom trawling, which is completely harmful to natural habitats, and hence does not allow for regeneration.

Although it may seem that every popular fish has been listed as “avoid,” remember that there is tremendous variety in seafood, more than in any other protein group. It is a very good idea to eat lower on the foodchain: sardines, clams, crabs, mussels, even jellyfish. Any species higher on the food chain should have been caught sustainably, by a smaller-scale fishery.

Consult any of the following websites for more information, especially for lists of ethical “good choices” fish:







Over the past half-century, ample attention has been paid to the rejuvination of sustainable food production. Grassroots movements have matured into highly organized organic certification bodies. Environmentalists and scientists have illuminated on the environmental and social externalities of intensive agricultural, meat, egg, and dairy production. What has lacked widespread public comprehension, however, is seafood. The origins of fish and marine-life remain largely esoterique, and the methods employed to capture these foods are generally poorly understood.


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One Response to “Unsustainable Seafood”

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