The Differences Between Wild-Caught and Farm-Raised Fish Explained
Fish has a reputation for being a high protein, low calorie “brainfood” thanks to its essential Omega-3 fatty acids. Just two servings a week can reduce your risk of heart disease and improve skin and hair. But did you know that not all fish are created equal?
The fish you buy in the supermarket can either be wild-caught or farm-raised. Farm raising fish has become a popular enterprise due to overfishing and the dwindling numbers of certain fish species in the wild.
While one method certainly sounds more natural than the other, is this really the case? Do farm raised fish offer the same health benefits as wild fish?
Defining “Wild-caught” and “Farm-raised” Fish
The practices of farm-raised and wild-caught fish are pretty self-explanatory. Farmed fish are bred and raised in tanks, ponds, lakes or other enclosures of water operated by agricultural workers. Whereas wild-caught fish are taken by fishermen in their natural environments, like the ocean.
There are also some fish that are technically both farm-raised and wild-caught. For example, young fish can be caught in the wild and taken to pens until they’re full-grown and ready to be sold to market. This can also work the other way round where fish are bred in hatcheries before being released into the wild.
Wild or Farm-raised fish, which one is more nutritious?
Farm-raised fish and wild-caught fish only have minor differences in their nutritional value. For example, farm-raised salmon has been found to have higher Omega-3 fatty acids than their wild counterparts because they are fed more often. In addition, the types of feed used in farms affects the fish’s diets, providing slight differences in their final nutritional value. Despite this, fatty fish such as salmon have higher levels of Omega-3 fatty acids than other sources of protein whether they’re farmed or caught in the wild.
Does one type of fish have higher levels of contaminants?
The toxin mercury typically occurs at higher levels in species of fish that are long-lived and higher in the food chain, regardless of how they were raised. This is because heavy metals such as mercury slowly accumulate in wildlife through a process known as bioaccumulation. As a result, species such as tuna, tilefish, shark, swordfish, marlin, and king mackerel typically have higher levels of mercury. On the other hand, more common fish species such as salmon, tilapia, trout, sardines and cod have low levels of mercury and therefore are safe to consume on a more regular basis.
When it comes to antibiotics, the debate around its use focuses on the possibility that these drugs promote drug-resistant bacteria or may still be in the meat that goes on market shelves. The environmental effect of antibiotics can also be very impactful. Cramped conditions within fish farms embedded in lakes, rivers, and oceans raise the probability of disease, and flushing antibiotics into the water can result in antibiotic resistant bacteria escaping into native populations.
Fortunately, the U.S. has strict agricultural regulations that prohibit the use of antibiotics and other drugs in farmed fish for anything except disease control. Furthermore, only 3 antibiotics are approved for use in farmed fish, which means that there are virtually no antibiotics that may carry through to human consumption. However it’s important to note that other countries may not have the same policies.
The push towards farm-raising fish comes after decades of overfishing in the wild. The numbers of certain fish species has dwindled to the point where more than 50% of seafood produced for human consumption is farm-raised. As one example, the number of cod in the northeast severely dropped in the 1990s, resulting in the closure of fisheries to allow repopulation. Unfortunately, the species has struggled to grow and its currently sustainability is questionable.
On the other hand, there are concerns that farms may leak contaminants or fish may escape into the wild. Although it is possible for organic waste and unused fish feed from farms to affect the habitat around the pens, the effects have been found to be temporary. In addition, the study of the escape of farmed fish into unnatural habitats has shown that domesticated fish usually do not have the instincts to survive in the wild very long and have not reproduced to the point of competing with native fish species.
So what do I buy?
The farm-raised vs. wild-caught debate is complex. A lot of fish contains higher levels of Omega-3 fatty acids than other sources of protein, regardless of whether or not they were caught in the wild. As a result, many sources encourage buying a mix of both types of fish simply to ensure that you are getting full nutritional value.
An even better solution is to expand the variety of fish you eat rather than just increase the quantity. This includes the consumption of invasive species such as Lionfish and Asian Carp, easing the pressure on declining wildlife populations who are threatened by these species such as Tuna and Cod. In addition, eating smaller fish such as sardines or anchovies is more economical and reduces your risk of exposure to mercury. With all of these considerations in mind, it is possible to continue enjoying seafood while staying healthy and helping the environment.