The Future of Sustainable Fish Farming

In a world of rapidly evolving technological advancements, there’s one industry that deserves its fair share of attention: sustainable aquaculture. As human populations continue to rise, the need for increased food productions stands a foremost concern for sustaining our future’s growing appetite. Like our ancestors before us, people are turning to the sea for the solution.

It’s a relationship that goes back for centuries, mankind and the sea. For years, humans have harvested food from the ocean, providing us with the rich and essential nutrients we need. Yet in recent decades, humankind has witnessed the decline of numerous ocean species, animals we once believed to be so abundant we couldn’t possibly alter their populations, let alone drive them to extinction. But that’s exactly what we’re doing – or more precisely, that’s the direction we’re headed. Experts say that over half the world’s wild caught fisheries are fully exploited, meaning that fish are being caught at the maximum rate to simply keep the population stable. Even more, over thirty percent of fisheries are overexploited, meaning that fish are being caught at a faster rate than they can reproduce, leading to the demise of the population and potentially the demise of the species itself.

So it seems the solution to the looming food crisis lies not, then, in the ocean itself, but in reaping the oceans benefits through something humans have been doing for quite some time, farming.

Aquaculture, otherwise known as “fish farming,” has been on the rise over the past few decades to meet the soaring demand for seafood. Farmed marine species currently constitute over half the seafood consumed worldwide, a number likely to increase as human populations continue to boom at a rate of over 100 million people per year. While farming fish and other marine species offers an alternative to overfishing wild populations, it’s not a perfect system and many aspects of aquaculture need increased scientific knowledge and technological advancement to become a viable source of food production in the coming years.

Current aquaculture methods are rife with environmental risks. The most common type of aquaculture is mariculture, the cultivation of marine organisms in the ocean or within an enclosed section of the ocean. This includes open-net pens and cages that place farmed fish in direct contact with natural coastal environments. As with many types of farmed animals, aquaculture faces challenges such as disease outbreak, feed production, and waste removal. However, by farming in an open system, the challenges go beyond the farmed animals themselves and often pose enormous risks to the surrounding environment. Infectious diseases among farmed fish can spread not only among cultured animals, but can also spread to native populations, introducing non-native diseases into the environment or facilitating disease through unsanitary conditions in densely packed farmed fish. Furthermore, non-native or genetically modified fishes can escape pens and potentially outcompete native species, threatening local fish populations in that area.

Another major issue in farming fish sustainability involves the use of their feed. The most common fishes people eat also happen to be the oceans top predatory fishes – tuna and salmon. These fish are not only large, but they are also carnivorous and require a diet high in fats. In order to feed and sustain these kinds of farmed fish, other fish species must be harvested from the ocean and therefore face pressures from overfishing. Current methods utilize “fish meal,” which combines fish oil, wheat products, and chemicals into pellets that are then fed to cultivated fish. This also poses a problem, as many carnivorous fish are not designed to metabolize large amounts of carbohydrates. The use of fish feed will continue to be an issue in the struggle for sustainable aquaculture until we find a way to provide sustainable food to farmed fisheries.

In an attempt to alleviate the environmental impact of fish farming, some forward thinking aquaculturists have turned to closed-contained systems, either solid-wall systems that float on the water or tank systems that operate entirely on land and perfecting their methods by successfully growing fish that are herbivores. By separating farmed species from native populations, both systems protect the environment from accidental fish escapes, limit the spread and transfer of disease and parasites between local and farmed fish, and decrease the amount of fish feed and waste excreted into the local ecosystem.

While solid wall closed-containment systems provide a better alternative to current aquaculture methods, there are still concerns in regards to sustainability and overall environmental impact. One of which includes the disposal of discharged water from the systems and their potential for contaminants into the external environment. Another barrier to sustaining these systems is energy, the high cost of pumping water through the system and maintaining the necessary electricity to meet the demands on a commercial scale.

However, innovative scientists from the University of Maryland’s Department of Marine Biotechnology have developed what they call a new generation of aquaculture technology, a closed-contained system that operates entirely on land and expels zero waste into the environment. Dr. Yonathan Zohar, one of the leading pioneers in the development of this technology, is a scientist and professor at the university’s Institute of Marine and Environmental Technology (IMET) spearheading the project. Committed to creating a sustainable, low-impact aquaculture system from the start, Zohar developed a system that recycles 99 percent of its water, with losses coming from evaporation. It brings in common household tap water, adds the necessary salt components, controls temperature and pH, and does it all for each specific species of fish. It also filters waste products from the fish through different microbial communities in order to detoxify the water and creates methane as a supplemental biofuel.

This land-based alternative aquaculture system provides fish a continuous supply of clean water, reducing the spread of pathogens, disease, contaminants, and toxins. It also allows for fish to grow more efficiently, as they don’t need to expend energy fighting currents like fish farmed in open-net pens would likely experience and can instead convert more energy into biomass. Zohar and his team also addressed one of the biggest obstacles in aquaculture, getting fish to reproduce at predictable cycles. By simulating environmental cues such as altering water temperature, lighting, and salinity levels, and then providing fish a pellet they created that mimics the hormone to induce natural reproduction, they were able to get predictable reproductive events.

The fish are clean, they grow faster, and they taste the same as fish you would eat from the ocean. A nearly self-sustaining system, its a combination of the latest in scientific knowledge and technology. Zohar’s system eliminates many of the detrimental environmental impacts from open-net pens and cages in coastal aquaculture production. Ultimately the goal would be to have such systems close to large urban areas where the demand for fresh fish is very popular. The environmental footprint of transportation would be drastically reduced thus reducing the emission of CO2. But like all growing industries, sustainable aquaculture still has many challenges to face.

It will take the continued efforts of scientists, government and policy-makers, and aquaculture industries to come together to solve these remaining hurdles to a sustainable commercial fish farming. We need to be conscious and aware of the efforts being put forth by scientists such as Zohar to invest in the advancements in aquaculture that address these major challenges in current fish farming practices. Our oceans can no longer provide us with enough fish to feed our rising population. As my father said in 1973, “With earth's burgeoning human populations to feed we must turn to the sea with new understanding and new technology. We must farm it as we farm the land.” The future of sustainable fish farming brings the sea to the land and gives us the opportunity to domesticate and harvest the species we need without directly burdening the ocean we rely upon.

In an effort to move towards a sustainable future, it will take not only innovative thinking but also global knowledge to make effective decisions. Aquaculture is a growing, and highly demanded industry. As the demand continues to grow, sustainability must remain a top priority and important aspect of future production. While improved technology is a big step in the right direction, it also requires the demand of the consumer. We are a part of the solution, and we can demand for a sustainable future.

Warm regards,