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What Is Farm-Raised Fish?
Farmed fish are commercially raised fish that live either in enclosures within oceans, lakes, and rivers, or in tanks. About half of fish worldwide (including what we eat in the United States) comes from farms. Some fish to try farmed include American Atlantic salmon (not commercially available wild), arctic char, rainbow trout, oysters, and tilapia (always farmed).
The Pros and Cons of Farm-Raised Fish
- Cost. Farm-raised fish are more readily available and less expensive than wild-caught fish, and they face some of the same problems as large-scale farms on land.
- Diet. Their feed can be made from lower-cost products or undesirable ingredients including antibiotics.
- Environmental impact. Pollution of natural habitats is also a concern with fish grown in open-net cages. A unique problem with farmed fish is that those raised in nets can introduce diseases and pests to wild populations: A few years ago in Norway, farmed salmon infected the country’s wild salmon with sea lice, significantly decreasing the population of wild salmon. Farmed salmon will also sometimes escape their enclosures, mating with and overtaking wild salmon species.
- Nutrition. Farm-raised fish tend to have higher fat content, since wild fish get more exercise, and because farmed fish are typically given feed high in fat from sources such as fish oil. That includes healthy fats such as omega-3 fatty acids, as well as saturated fat. Wild-caught fish may contain more trace minerals, while farmed fish may contain more sodium. Nutritional differences between farmed and wild-caught shellfish, however, are minimal.
What Is Wild-Caught Fish?
Wild fish are fish caught in their natural environments. Their diets may be higher-quality and more diverse than those of farmed fish; they are not fed antibiotics. Wild seafood tends to be more expensive than farmed, and has its own environmental issues, such as overfishing and bycatch.
When purchasing wild fish, pay attention to how it was caught: Long-line fishing can lead to bycatch, so look for “pole-caught,” “troll-caught,” and/or “FAD-free” if that’s a concern. The blue-and-white Marine Stewardship Council (MSC) logo means that fish is certified sustainable. Larger fish are more vulnerable to overfishing, so diversify your diet with a smaller fish, too. Some wild fish to try are wild Alaskan salmon, Atlantic mackerel, and sardines, and sockeye salmon (always wild).
What to Know Before Buying Fish
There are advantages and disadvantages to both wild-caught and farm-raised fish. When sourced responsibly, wild-caught fish is the paradigm, and they are usually harvested in less polluted waters. Unfortunately, the demand for wild-caught fish has caused over-harvesting and sometimes unsustainable practices. Farm-raised fish can yield excellent quality when farmed correctly and responsibly, resulting in product consistency, size, and flavor. Additionally, farm-raised fish can help in sustainability. Some of the potential disadvantages of farm-raised fish include overcrowding, polluted waters, and lower-quality feed given to the fish.
In addition to nutrition, flavor, and environmental impact, contaminants, including mercury and PCBs, may play a role in which fish you choose. Mercury levels are a concern for all ocean-raised fish, whether they grew up in an enclosure in the ocean or were caught wild. Smaller fish such as anchovies, herring, sardines, and shellfish tend to have lower mercury levels than larger fish such as swordfish. When buying tuna, choose “light” tuna (skipjack) for the least mercury.
Both farmed and wild fish can contain PCBs (polychlorinated biphenyls), toxic compounds that were banned in the U.S. in the late ’70s but still exist in sediment at the bottom of bodies of water and build up in animal fat. PCB levels depend both on species and where fish was caught. Bottom-feeding fish (such as American eel, sea trout, and striped bass) and predator fish (bass, lake trout) from contaminated areas will have more PCBs, and farmed salmon whose feed includes ground-up fish have more PCBs than wild salmon.
With so many variables to consider, don’t be afraid to ask your fishmonger lots of questions. Our oceans may seem infinite, but their resources are not. Educate yourself on issues surrounding sustainability and seafood. Before buying fish or shellfish, find out where and how it’s caught. If it’s farm-raised, learn about the farm’s management practices.
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