Aquaculture, also called aquafarming, is the process of commercially farming fish or other marine life such as mollusks, crustaceans, or marine plants for consumer purposes
As the demand for seafood rises, aquafarming shows promise as a solution that will help meet it. However, not all aquafarming techniques and processes are created equal. While the act of aquaculturing marine life for food has been happening for thousands of years and definitely has benefits, some modern practices have gained controversy. Discover the pros and cons of aquaculture and what you can do to ensure your seafood comes from a sustainable source.
Aquaculture is a source of global food security
With 7.6 billion people on earth, providing enough food for our growing population is becoming more difficult. Wild fish stocks are rapidly declining due to the sustained pressure of overfishing as well as the many side effects of climate change and plastic pollution. Our once-invincible Big Blue is now a finite resource. Aquaculture could be the solution to providing a sustainable source of seafood and relieving pressure on certain wild stocks as well.
In the United States, for example, aquaculture production represents 21% of total seafood production and fisheries products by value. But despite the average American consuming over 15 pounds of seafood a year, over half of our seafood is imported from Asia. The United States is currently 16th in global aquaculture production and growing by about 1% every year. As better technologies advance, aquaculture could become the new norm of seafood production to feed a growing world.
Aquaculture creates local jobs and increases city revenue
Although starting an aquaculture farm is financially and structurally challenging, the profits and benefits to local communities can be enormous. For example, the shellfish aquaculture industry in Massachusetts was valued at approximately $25.4 million in 2013. This generated about $45.5 million in revenue for the local economy and produced jobs for nearly 1,000 citizens. In Maine, the aquaculture sector had a direct economic impact of $73.4 million in output in 2016.
Aquaculture can assist in removing pollution from local waters
Bivalves are filter feeders and their presence often removes pollutants and excess nutrients in the water, such as phosphates and nitrates from agricultural fertilizers. A two-inch oyster can filter up to 50 gallons of water per day! At a commercialized scale, this means one oyster farm could filter between 15 and 40 million gallons of water daily. Not only do many aquaculture farms produce food, jobs, and revenue for local economies, but they can also benefit the surrounding marine ecosystem when they’re set up and managed properly.
Some aquaculture farms, particularly fish farms, can induce excess fishing pressure on feed stocks that are used for food pellets
Many farmed fish species are carnivorous, and therefore require a diet that consists of smaller fish. A recent study has shown that up to 90% of the global fish catch is food-grade, meaning it’s used as a source of protein in animal feed—including larger fish! Tuna and salmon, two popular farmed species, need to eat up to five pounds of smaller fish like anchovies and herring per pound of body weight. This creates some debate around the usefulness of aquafarming, with some questioning whether fish farms actually produce more fish or if they simply convert small, lower-value fish into bigger, high-value fish.
Fish farm stocks are usually high-density, with a higher potential for disease transmission
Over half a million salmon have died from a sea lice outbreak in New Brunswick’s Passamaquoddy Bay in 2016. Salmon farms, like many others, are often maintained in sea pens that extend along the coastline and have high potential of interaction with wild populations. With many fish farm stocks being high-density (meaning, numerous fish are packed into a relatively small area) with a generally low genetic diversity, sea lice and other parasites and diseases are better equipped to spread quicker amongst farm stocks and even mix between wild populations. These outbreaks are not only catastrophic for local businesses, but the environmental impacts are costly as well.
With so many fish in one area, waste and toxins are produced that pollute local waterways
Fish farms often use chemicals in the form of antibiotics and pesticides to reduce disease and parasites amongst farmed stocks. Since the only barrier between fish stocks and the surrounding environment is usually a high-grade net, these chemicals often leach into nearby waterways and impact local species. Additionally, fish waste and uneaten food accumulates on the seafloor underneath fish farm pens, smothering benthic marine plants and animals with excess nutrients.
Coastal habitats are often destroyed to make room for aquaculture
Mangrove forests and estuaries are crucial nursery habitats for young fish that eventually make their way to the open ocean. Many tropical countries utilize this rich area to rear aquaculture species such as shrimp and fish, but the intensive farming practices produce lots of waste. After a certain amount of time, aquaculture farmers may need to relocate to a new area, where more pollution and destruction may also occur. Destroying pieces of local habitat not only aesthetically ruin marine ecosystems, but ecologically damage them. Clearing away certain marine habitat for aquaculture practices may also reduce the amount of local fish residing in that area, further hurting local fishermen that make their living via wild stocks.
While aquaculture does present many benefits, especially for bivalve species, its current drawbacks leave something to be desired. With the global population presenting no evidence of slowing any time soon, it’s clear that new solutions need to be created and adopted on a much larger scale to ensure seafood demands can be met sustainably.
To make an impact at an individual level, you can support local fisheries that practice sustainable farming methods. The Aquaculture Stewardship Council (ACS) works to certify environmentally and socially responsible seafood. Look for their aqua-green label, which can be found on many seafood products around the world!
Additionally, the Monterey Bay Aquarium has a Seafood Watch program that contains updated information about which seafoods are best to eat and avoid based on how they're caught and/or raised. It allows consumers to stay knowledgeable about what they’re eating.
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4Ocean is partnering with SeaLegacy throughout the month of August to advocate for marine protected areas and support sustainable fisheries around the world.