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.
New Technology
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
Closed-contained fish farm systems are the future in this business
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.
Continued Effort
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, it’s 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 high. 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.
The OFS expedition team dived a BC salmon farm, some of which are extremely detrimental to the marine ecosystem of the Pacific Northwest
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 in-demand, 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 a sustainable future.
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