Aquaculture has been praised as the savior industry that will simultaneously feed billions of people and relieve pressure on wild populations of finfish and shellfish. However, as much we want aquaculture to be the perfect model for the future, like any large-scale industry it has its share of problems. Arguably one of the most desired fish on the market is salmon – rich with nutrition, low in mercury, and fantastically succulent in countless recipes, salmon seems to be a near-perfect fish. With some wild populations declining, the consumer eye is turning towards aquaculture to supply the demand for quality salmon.
Salmon farming – to the dismay of many seafood lovers – has been plagued with problems. They have yet to produce a product with the same quality as the wild version. Salmon are anadromous, a complicated life cycle wherein the fish spends time in freshwater, brackish water, and saltwater. This is highly difficult to replicate in a fish farm setting. Another, perhaps more pressing issue has been rising to the attention of salmon farmers – this robust fish happens to be predatory. That means in order to grow to a healthy state, they need LOTS of protein and nutrition to meet their metabolic needs.
Salmon and other predatory fish that are farmed have traditionally been fed fishmeal and fish oil. These products are made from catching and concentrating wild populations of forage fish like herring, sardines, and anchovies. With the multitudes of salmon farms popping up all around the world, there has been a tremendous increase in fishing pressure on forage fish. These forage fish are an essential component of the ocean food web, serving as the base food for larger fish, invertebrates, marine mammals, and sea birds. Lower populations of forage fish means fewer larger species and a decrease in overall diversity and numbers of other commercial species. Forage fish are also one of the most nutritious fish for human consumption – so it’s in our best interest to keep them around!
Because of this increasing pressure on forage fish populations (and due to the skyrocketing cost of fishmeal) alternatives for feed have been intensively researched. Many salmon farms have turned to plant-based feeds (terrestrial plants that is) because they are cheaper. Unfortunately, these plant feeds do not have the nutrients required for salmon metabolism to thrive. Their digestive systems are not able to break down starch based feeds, and as a result the fish don’t receive nearly the amount of nutrients that they need. They contain much less omega-3s than wild salmon, and their immune systems are compromised. Overall the end product is a fish devoid of nutrition and taste, two of the main reasons consumers eat salmon. What is the point of buying a tasteless fish that offers few health benefits?
Fortunately, one company is coming to the rescue of salmon aquaculture. Ocean Harvest Technology in Ireland has developed a salmon feed based on seaweed. Fish can’t synthesize their own omega-3s, much like us. Much of the naturally occurring omega-3 fatty acids in our seafood comes from steady diets of seaweed and algae in the ocean. Zooplankton eat algae, little fish eat the zooplankton, big fish eat the smaller fish, and omega-3s accumulate up the food chain. Salmon did not evolve to consume food based on terrestrial plants – that is why they suffer so much on cheap plant oils. Seaweed contains a different kind of nutrition, the kind that salmon bodies are used to receiving and thriving on in the wild.
The salmon that were fed this new seaweed-based feed benefited tremendously from the added nutrition of a natural food item, containing 62% more omega-3 content than salmon that were not fed the seaweed diet. The feed also boosted their immune systems, making them better able to fight off parasites, infections, and diseases. The salmon of course cannot survive on seaweed alone, but as a supplement it has excellent implications.
A huge advantage to creating a feed based on algae or seaweed is that it would likely be very cost-effective. Some seaweeds are known to grow two feet every day. Microscopic algae, given the right amount of nutrients and sunlight, can bloom to massive numbers in a short amount of time. By harvesting the right kinds of seaweeds and algae, we could harness a fantastic amount of nutritious product for fish farms, while keeping a low cost for the feed that the farms could afford.
If seaweed-based feed were to become widely distributed for all salmon farms, we could cure a long-lasting ailment of salmon aquaculture. A purer, healthier farmed product would enter our markets, taking the pressure off of wild populations and expanding the sustainable choices for seafood consumers. The farms themselves would make a greater profit, expanding the aquaculture industry and providing more jobs with a greater income.
There is so much potential for growth in the quality and production of aquaculture. It is vitally important that we take the time and energy to research opportunities like using seaweed-based feed for farmed fish. We hope you will join us in celebrating all the successes of this industry to provide consumers with healthy, delicious and sustainable seafood products. Help support these efforts by purchasing your seafood products from distributors that carry a sustainability label from the Marine Stewardship Council, such as Pucci Foods.