If you are among the millions of people who enjoy consuming fish and shellfish, yet you are concerned about the declining state of the world’s fish populations, you might be thinking about giving up your seafood habit for good, or cutting back drastically. The good news is that you don’t have to do this; there are many excellent seafood choices available that don’t make a negative impact on wild fish populations or on the environment. On the other hand, simply because that package in the supermarket says the fish it contains grew up on a fish farm, doesn’t mean you should take it right home. Let’s take a closer look at deciphering which farmed fish and shellfish are great choices and which are not.
Fish Farming: The Basics
Over a billion people worldwide rely on fish as their major source of protein, yet there are only so many fish in the sea. Fish farming, sometimes referred to as aquaculture or mariculture, is a way to raise fish in captivity until they reach market size. In theory, this method of “fishing” should be a better alternative than pressuring wild fish populations; in truth, some methods of fish farming are detrimental to the health of the fish, and to your health as well. There are several different methods of fish and shellfish farming in which over 100 different species are raised specifically for consumption:
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Composite Fish Culture – Developed by the Indian Council of Agricultural Research during the 1970’s, this system is one in which several species are placed in a containment system to live with one another where they interact as they would in a natural environment. Each fish plays a role in the artificial ecosystem, with some cleaning up after others. This is an efficient system that allows farmers to produce thousands of pounds of fish per hectare each year.
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Open Net Cages and Pens – These enclosures are used to contain fish like salmon in freshwater lakes and offshore coastal areas. Because water from the outside area circulates freely through the pens, and because fish waste passes into the environment unchecked, nearby wild habitat is affected. In addition, some of the fish kept in these pens are non-natives; if they escape, they can compromise local wild populations by competing for resources or interbreeding. As fish are often kept in close quarters inside these cages, they are susceptible to sea lice and other parasites, and they are susceptible to disease. Both disease and parasites can be passed on to wild fish that come near the pens.
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Ponds – Ponds vary in construction and in the amount of pollution they release to nearby environments. They are designed to enclose fish and shellfish, such as tilapia, catfish, and shrimp; and while some responsible pond owners contain and treat waste water, others simply discharge it, allowing it to pollute nearby waterways, groundwater, and the rest of the surrounding environment. The construction of shrimp ponds in mangrove forests, in places like Vietnam and Thailand, has destroyed millions of acres of coastal habitat, affecting birds, fish, and human populations alike. Today, in Thailand and in some other places, mangrove rehabilitation projects are underway, and pond farming is becoming a better practice than it once was.
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Raceways – Long channels designed to contain fish like trout and salmon, these concrete streams usually utilize water that is diverted from a natural source or obtained from a well. Water from raceways is normally treated prior to being diverted back to the source or released. This method tends to be extremely viable, since the governmental agencies in countries where it is most popular tend to require strict regulation and monitoring of both nearby water quality and onsite water quality. In the United States, where this method is used extensively for raising trout both for consumption and for release into the wild, water quality is of utmost importance.
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Recirculating Systems – Almost any finfish can be raised in recirculating systems; these tanks utilize water that is treated and completely recycled, over and over. Striped bass, sturgeon, salmon, trout, and others are often raised inside these systems, which do not place an undue impact on the environment. They do use electric power sources and are costly to operate, so fish from these systems can be pricier; but issues like escaping fish, disease, and water waste are circumvented.
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Shellfish Culture – In shellfish culture, farmers raise clams, mussels, and oysters in mesh bags, plastic trays, or on ropes, where the filter feeders simply grow and thrive, so long as water is clean. Most of the time, this works very well, as the shellfish help to keep excess nutrients at bay, but in areas where little tidal flow or current exists, pollution can occur.
Problems With Farmed Fish
Just as mammals and poultry living on farms topside are kept in conditions that vary from excellent to abysmal, so are farmed fish kept under a variety of conditions. In developing nations, particularly, problems are prevalent. For instance, some fish are raised in areas where each fish has less space than the size of an average bathtub to itself. Living in overcrowded conditions like this increases disease and causes physical injury to the fish; often, they suffer from broken fins and severe stress. In nations where these methods are used, fish are often fed high amounts of antibiotics like their counterparts on land are; and, they are sometimes given medications that have been banned in the US, Canada, and Europe. These medications end up in fish flesh, and on the dinner table. In addition, they add to pollution and can harm wild marine life.
Some farmed fish are fed with fish meal obtained through processing wild feeder fish caught with invasive fishing methods like bottom trawling and gillnetting. Not only does this put pressure on wild fish populations, it can cause damage to ocean environments. Other farmed fish are being fed with processed foods they were never meant to eat; for instance, genetically modified corn is finding its way into fish food and leaving toxic residues behind in the fish’s bodies.
Some fish are being genetically engineered, themselves. Designed to grow two to four times as fast as wild salmon, these fish could damage native species if they escape, eventually causing extinction. While these transgenic “frankenfish” are not yet being raised in great numbers, organizations like Greenpeace, the National Academy of Sciences, and others are raising an outcry. The FDA is considering allowing the fish to be placed on the market; grocers and restaurateurs are pledging not to carry the new fish.
How to Choose the Best Fish
Most farmed fish from the United States, Canada, and the EU are good choices since regulations are well enforced, fish health is monitored, and environmental impact is kept at a minimum. In some Asian nations, fish are farmed along with plants, and their waste is used as a natural form of fertilizer; this method is catching on in places like China and Thailand.
Still, simply reading a label and seeing where a fish is sourced is no guarantee that you’re actually making the best choice. In order to make the selection process easier, organizations like the Marine Stewardship Council, NOAA’s FishWatch, Monterey Bay Aquarium’s Seafood Watch Program, and Canada’s Sea Choice offer easy to access online information about which fish, from which areas, are sustainable seafood choices. In addition, you can look for the Marine Stewardship Council’s Certified Sustainable Seafood label, which features a white fish on a blue background, whether you’re choosing wild caught fish or farmed fish.
Over seventy percent of the world’s wild fish populations have been completely depleted or are still being exploited to the point where numbers are rapidly declining and low rates of reproduction are causing further decline. It is estimated that around fifty percent of the world’s fish come from farms. Selecting the right ones allows you to make a statement with your food dollars, plus it is better for the environment and for your health.