Where Does Your Fish Come From: A HealthCentral Explainer
The meat and poultry industry receives its fair share of media exposure through documentaries, published studies and reports on the workings of industrial meatpacking plants. No big surprise there since the meat industry is the largest segment of U.S. agriculture and has undergone a radical transformation as mass production lots have replaced small cattle farms.
Less understood, however, is the fishing industry. The two main types of fish—farm-raised and wild-caught—present different pros and cons. Here are some frequently-asked questions and what you need to know when it comes to buying and eating fish.
What fishing methods are used?
The world’s supply of seafood either comes from aquaculture (also known as aquafarming)—the farming of aquatic organisms, including fish, crustaceans, mollusks and aquatic plants—or from fisheries, defined as a group of species that share the same habitat or the activities involved in catching a species of fish.
Aquafarming has become the fastest growing form of food productionin the world, as aquaculture production has increased to meet rising seafood demands. About half of the world’s seafood supply comes from aquaculture, and this percentage is expected to increase in coming years. Currently, Asia accounts for about 89 percent of global aquaculture production. Countries that produce the most aquaculture are as follows, from most to least: China, India, Vietnam, Indonesia, Thailand, Bangladesh, Norway, Chile, the Philippines, Japan, Egypt, Myanmar, United States.
The other half of the world’s seafood supply comes from fisheries. However, part of the reason why aquaculture production is expected to increase in coming years is because the world’s fisheries are declining, mainly due to limited or no oversight for many of them.
How are fish farmed?
When you buy fish labeled as farm-raised, the fish was farmed using one of the methods below:
- Bag/rack: Bags are set up on racks above seabeds, in which fish from hatcheries are cultivated.
- Hatchery: Hatchery fish are bred in nurseries and are either used in aquaculture or are released and caught in wild-capture fisheries.
- Open net pens or cages: Open net pens or cages are placed in offshore coastal areas or in freshwater lakes. Open pens and cages present multiple risks, including waste from the fish polluting wild habitat and diseases and parasites spreading to nearby wildlife.
- Ponds: Ponds can be either fresh or salt water and are either costal or inland.
- Raceways: Farmers use raceways to divert water from a waterway, like a stream or well. In the U.S., raceways are typically used to raise rainbow trout.
- Recirculating Systems: These systems raise fish in tanks through which water is treated and recycled. Recirculating systems can raise almost any finfish species, such as striped bass, salmon and sturgeon.
- Shellfish culture: Farmers sometimes suspend shellfish such as oysters, mussels and clams in water by ropes, plastic trays or mesh bags.
- Submersible net pens: Pens or cages are submersed in water can be used for a variety of fish species.
- Suspended culture: Shellfish, such as oysters, mussels and clams can be grown on ropes, nets, trays or mesh bags that are suspended in water.
- Tuna ranching: Ranching is typically used for carnivorous top predators, such as bluefin tuna, and entails capturing a species then growing them to harvest size on farms.
How are fish caught?
Types of fisheries include commercial fisheries, subsistence fisheries and recreational fisheries, among others. Below are the more common fishing methods and what they entail:
- Bottom trawl: This type of net is pulled along the seafloor to catch shrimp and bottom-dwelling fish like halibut and sole.
- Dredge: Dredges are large, metal-framed baskets that are pulled across the seafloor to collect shellfish such as oysters, clams and scallops. When the metal teeth dig into the floor, however, it can negatively affect seafloor habitat and bottom-dwelling species.
- Gillnetting: Curtains of netting are suspended by floats and weights. Gillnets are often used to catch sardines, salmon and cod, but because the nets are invisible to fish, they can accidentally entangle other animals.
- Harpooning: Fishermen sometimes use an aluminum or wooden harpoon to catch large fish such as bluefin tuna and swordfish.
- Jig: A jig is a type of hook that is attached to a line, which fishermen use to hand-catch fish.
- Longlining: Long lines—anywhere from one to 50 miles long—are strung with smaller lines of baited hooks. Depending on where the lines are set up, longlining can be used to catch a wide range of fish.
- Midwater trawl: Trawlers are ships or vessels that pull large nets through the ocean. They are used to catch entire schools of fish at one time.
- Pole/troll: Fishermen sometimes use the more traditional method of using a pole and line to catch open-ocean fish and bottom-dwellers. The downside of this method is that only one fish can be caught at a time.
- Purse seining: This method entails encircling schools of fish with a large net, which fishermen pull closed to herd the fish into the center.
- Seine net: Seines are small-meshed nets that fishermen suspend in the water and drag to catch and herd fish.
- Traps and pots: Wire or wood cages are submerged into the water—usually on the ocean bottom—to catch lobsters, crabs, shrimp, sablefish and Pacific cod.
- Trolling: Trolling entails towing lines with hooks behind or alongside a boat and is typically used to catch salmon, mahi mahi and albacore tuna.
Where do fish come from?
About 90 percent of the fish consumed in the U.S. comes from other countries. Below are the countries from which certain types of seafood are imported:
- Shrimp: Asian countries and Ecuador
- Atlantic salmon: Canada, Norway, Chile
- Tilapia: China, Indonesia, Ecuador, Honduras
- Scallops: China, Canada, Mexico, Japan, Argentina, Philippines
- Mussels: Canada, New Zealand, Chile
- Clams: Asian countries, Canada
- Oysters: China, South Korea, Canada
How are fish regulated?
In the U.S., various state and federal agencies, including the U.S. Food and Drug Administration (FDA) and the Department of Commerce, work together to ensure that seafood grown in the U.S. or imported is safe for consumers. The FDA runs a fish inspection program for both domestic and international seafood processors and retailers to ensure that no hazards, such as toxins, chemicals and environmental contaminants, are present. The National Oceanic and Atmospheric Administration (NOAA), which is a part of the Department of Commerce, also provides inspection services. International countries, however, have different levels of regulation. Because the vast majority of fish consumed in the U.S. come from other countries, each type of imported fish may have different implications for the consumer’s health and for the environment. Below are some common areas of concern:
- Environmental impact and sustainability: Both wild-caught and farm-raised fish have the potential to harm the environment. Some of the methods used for catching fish harm both the ecosystem and other fish. With aquaculture, various practices can pollute the water and threaten local flora and fauna. Whether fishing practices harm the environment depends largely on who is doing the fishing and/or farming. For example, in the U.S., fish farming regulations are relatively strict—any water that is discharged into the environment, for example, must be as clean or cleaner than it was when it came in.
- Hormones and antibiotics: Consumers who are concerned about the use of hormones or antibiotics are better off consuming fish that was produced in the U.S., as U.S. regulations prohibit the use of hormones and antibiotics to promote growth in farmed fish. Regulations overseas, however, do not always prohibit using hormones or antibiotics. Also, there are currently no genetically modified fish for sale in grocery stores in the U.S.
- Contaminants: Two contaminants that consumers should be weary of are PCBs and mercury. PCBs (polychlorinated biphenyls) are man-made, potentially carcinogenic chemicals found in both farmed and wild-caught fish. The majority of evidence has not proven whether farmed or wild fish contain more PCBs. PCBs are mainly stored in the fat, so consumers can reduce their exposure by avoiding fatty parts of fish and by following safe fish handling and cleaning procedures. Consumers may also be concerned about mercury levels in fish. Levels have been found to be relatively low in commonly farm-raised fish, such as salmon, tilapia and catfish. Wild-caught fish, such as swordfish, king mackerel, tilefish, shark and tuna typically have higher levels of mercury.
Given the numerous fishing methods both in the U.S. and elsewhere and different countries’ regulations, it is nearly impossible to know how the seafood you’re buying at the store or eating at a restaurant was produced. However, there are numerous resources available which consumers can use to learn about current issues and stay educated about the constantly-evolving industry practices.
One good resource is the Seafood Watch program at the Monterey Bay Aquarium, which provides recommendations for consumers and businesses on which seafood items are “best choices,” “good alternatives” and which ones people should “avoid.” Seafood Watch also provides pocket guides and apps to help raise consumer awareness. Here are additional seafood resources organized by continent.