Understanding the Issue
When choosing what fish to buy and eat, different concerns come into effect. The healthiest fish might not be the one with the least environmental impact. In addition, the debate about whether wild or farmed fish is better remains controversial. Farmed fish already account for half of the world’s fish consumption and that percentage grows every day, but there are many concerns associated with fish farms. However, wild fish stores are significantly depleted due to human consumption and depending on the ocean to provide more fish could place those ecosystems in more danger.
Unlike the meat industry, awareness about the sustainability, health, and animal welfare concerns in the aquaculture industry is not widespread. This page attempts to describe some of the current conflicts in the fish industry.
Farmed Fish Concerns
The term ‘Aquaculture’ refers to any aquatic organism, but fish farming is by far the most popular form of aquaculture. Although about half of all fish sold is farmed, the industry is still new and did not become well known until the 1970s. Due to the rise in fish farming, production of seafood worldwide has increased dramatically. The most popular species in fish farming are carp, salmon, tilapia and catfish. Read more about fish farming techniques here!
Farmed fish are also very tightly concentrated- much more so than in the wild. Their limited space also forces them to rub against each other and the sides of their cages which damages tails and fins. Similar to compacting cows and chickens, farmed fish often become diseased and are given antibiotics. By eating the fish, humans consume part of the antibiotic which can make bacteria more resistant to antibiotics in the future.
Despite fish farming being a breakthrough in feeding the world, there are issues concerning the welfare of the fish and the environment they live in. Some farmed fish, such as tilapia and carp, do not need animal protein in their diets. These fish are fed food derived from vegetables, which is more environmentally sustainable because they do not depend on the ocean’s depleted stores for sustenance. However, carnivorous fish, such as salmon, need to eat other fish. Although the salmon are farmed, the fish they eat are caught from the wild. Several pounds of other fish are required to produce one pound of salmon, clearly an unsustainable method. Catching fish to feed to farmed carnivorous fish reduces the already substantially decreased wild fish population.
Escaped Farmed Fish
Because most farmed fish are kept in open nets, they can escape into the wild. When wild and farmed fish come into contact, it can endanger the wild fish by outcompeting them. Wild fish species are already at risk due to overfishing so this endangers them even more.
Effects of Fish Farms on the Environment
The large quantity of fish kept in one location often leads to habitat destruction. The waste that the fish produce is often contaminated from drugs and flows unrestricted into the ocean. Bacteria from the fish can consume all of the oxygen in the water, making that area uninhabitable for any species.
However, if farmed fish are grown in an area with a strong current, their waste is swept away more quickly. Strong currents also help fish growth.
Read more about the environmental impacts of salmon farming in specific here.
Some scientists at the University of Maryland have a different idea of how to farm fish that is more sustainable, read about it here.
What is the best kind of fish to eat?
Fish that is lower on the food chain has less of a negative environmental impact. Eating fish that were fed vegetables instead of other fish takes pressure of the ocean ecosystems to provide enormous amounts of seafood for humans. Some examples of farmed fish that are generally fed vegetarian diets are tilapia and rainbow trout. This is particularly important because humans have considerably depleted the ocean’s resources. However, fish with vegetarian diets often do not have comparable health benefits to carnivorous fish like salmon. Tilapia, for example, has one tenth the amount of Omega-3 fatty acids compared to salmon. The soy based diet that farmed tilapia eats also makes the fatty acids it has less healthy. Read more about tilapia farming here.
Salmon is a carnivorous fish, so it has a highly negative environmental impact, even when farmed. However, salmon has the highest amount of Omega-3 fatty acids of any fish. When comparing wild and farmed salmon, wild salmon has fewer calories, sodium, fat, and more calcium, which make it healthier overall. Click here for more information on comparative nutritional values of wild and farmed salmon.
Other fish with high contents of Omega-3 fatty acids are Arctic char, Atlantic mackerel, sardines, trout, and black sea bass. For more information, check out this healthy fish guide.
Whole Foods advertises that it has high standards for farmed fish that it sells. Their website details what they require for each type of farmed fish.