Most people know that they should look at the nutrition label of the foods they’re buying (even if they’re not necessarily doing it). When we look at the label, most of us are looking at fat and sugar contents to determine how healthy a given food might be for us. Some even go a little further and dissect the ingredients.

But are you looking at where your food comes from? Everyone knows fish is supposed to be good for you (which it generally is), but the source of the fish eaten can have a large impact on not only the composition of the fish itself, but also the health benefits that come with it. Most large grocery stores have a section for fresh seafood where you can pick up non-frozen goodies like shrimp, lobster, cod, tilapia, salmon, etc. These fish are often wrapped right in front of you and might come with a label with some ingredients. But it’s just fish in there right? How can that be bad?

If the fish you selected came from a farm, rather than being wild-caught, there may be some things you want to know about it. A report from the Environmental Working Group in 2003 found that farmed salmon has the highest levels of toxic man-made contaminants than any other fish, with other types of farm-raised fish following closely behind and many wild-caught fish lower down on the list. Also, according to the United States Department of Agriculture, a small fillet of wild salmon has over 100 fewer calories than the same weight of farm-raised salmon, partially due to about a 20 percent increase in saturated fat content.

If you want to know more about possible contamination issues, try finding out where your fish is coming from and research any hazards that may seep into fish farms.

However, subsequent studies have shown that these raised levels of contaminants are still not high enough to be of any serious health concern; the health benefits of fish still significantly outweigh the negatives. Fish, especially salmon, are a great source of protein and healthy, essential omega-3 fatty acids.

So on an individual level, eating farmed fish may not necessarily be worse than wild fish. But fish farms do have environmental or population-wide concerns. Farming fish has become institutionalized, and like any institution, it has its procedures and routines for raising the fish. This means the fish are often fed the same feed for each meal. In the wild, fish are able to eat a variety of foods that contribute to the diversity of nutrients they consume; farmed fish generally do not have the same nutritional content due to the monotony of their diet. Farmed fish are also treated with antibiotics that can be dangerous when distributed to large amounts of the human population. These widespread antibiotics contribute to the growing populations of antibiotic-resistance bacteria that can then become harmful to both you and me.

Environmentally, farming fish is generally not sustainable. Contrary to what many people may think, farming fish actually contributes to overfishing. Many of the popularly farmed fish are carnivores, such as salmon, tilapia and carp. Their feeds consist of other smaller fish that must be fished in large quantities, upsetting the aquatic ecosystem for wild fish who rely on those smaller fish in their diets. For example, about three to four pounds of small fish (sardines, anchovies, mackerel) are required to grow one pound of salmon fillet.

Fish farms also consist of heavily concentrated areas of fish, leading to large amounts of concentrated fish waste accumulating near the farms. This waste allows for the breeding of large amounts of bacteria that threaten wild aquatic life.

An advantage of farmed fish is the lower levels of mercury and related toxic metals that are found in wild-caught fish like salmon and tuna. Both farmed fish and wild-caught fish have advantages and disadvantages, and as the consumer, you are free to choose which positives and negatives weigh more heavily to you according to your personal values. Health-wise, farmed fish and wild fish seem to be roughly equivalent, with each having a different set of benefits and risks. Environmentally, choosing wild fish is probably the better option.

But the best option might be to try and switch over to eating the smaller fish (anchovies, sardines, mackerel): a more sustainable and healthier option. These smaller fish have shorter lives and do not eat other fish, meaning they cannot accumulate nearly as many toxins per gram as predator fish.

Unfortunately, there is no clear right or wrong option. Next time you’re at the supermarket, think about looking up where your fish is coming from. The choice is up to you!

Nicholas Remillard can be reached at [email protected].