August 8, 2016|By Steve Summerfelt| Food

For nearly 30 years, the Freshwater Institute has worked to find solutions to some of the most pressing issues at the intersection of food, water and the environment. We have made great strides in finding better ways to use, reuse and conserve our water resources, from helping farms and communities address water quality constraints to finding ways to meet the ever-increasing demand for seafood in an eco-friendly way.

When we talk about healthy food systems, seafood is an important part of the conversation. However, you might assume that unless you live near an ocean, seafood is not going to be part of the local food system (more than 90 percent of the seafood we currently eat is imported). That is one of the things we at the Freshwater Institute—landlocked in Shepherdstown, West Virginia—are trying to change. As our oceans have fallen victim to overfishing, it is becoming increasingly important to find a way to meet rising seafood demands without damaging our oceans. That is why we have researched and developed recirculating aquaculture systems (RAS) technology that makes it possible to farm fish on land in a system that reuses water, repurposes waste, and allows fish to be produced close to the local market.

Freshwater Institute Tank Scott TsukudaThe RAS tanks at The Conservation Fund's Freshwater Institute in Shepherdstown, West Virginia make it possible to reuse 99 percent of water, filter out solid waste and promote healthy, active fish. Photo by Scott Tsukuda.

We are constantly trying to improve our methods, to find ways to be even more sustainable. Every cohort of salmon we raise is a trial testing some aspect of salmon growth or production technology, such as the impact of feed formulation, fish density, or strain of salmon. Most recently—with support from the Atlantic Salmon Federation, the Gordon and Betty Moore Foundation, and SalmoBreed AS of Norway—we have focused on evaluating the effects of a fishmeal-free diet for Atlantic salmon raised in our RAS facility, including the health of the salmon and the quality of its filet as it grows to market size.

As we seek more sustainable ways to supply the world seafood through aquaculture, we also have to find better ways to feed the fish that we are raising. A primary sustainability goal has been to minimize and, if possible, eliminate the use of wild harvested fish when producing farmed fish. To this end, we tested a fishmeal-free sustainable Atlantic salmon diet formulated by Dr. Rick Barrows of the USDA Agricultural Research Service—which has provided funding for Freshwater Institute research for more than two decades—and Jason Mann of EWOS Canada to meet sustainability requirements set by the Freshwater Institute. The diet contained only byproduct fish oils—sourced from a white fish processing plant in Oregon—that provide high levels of heart- and brain-healthy Omega-3 fatty acids. Because no additional wild fish were caught or farmed to produce these oils, the end-product maintains a zero fish in:fish out ratio as defined by the Monterey Bay Aquarium’s Seafood Watch program. It was also produced using entirely North American sources for the major ingredients. The diet contained no genetically modified ingredients, and used natural pigments and only by-products from human food sectors. EWOS Canada/Cargill, which produced the feed, hopes to market this diet to commercial salmon farmers, which would not only be arguably the most sustainable fish feed to hit the market, but is also cost-competitive with conventional fish feed.  

We began feeding this diet to Atlantic salmon post-smolt—a stage when the fish is mature enough to move from freshwater into seawater and a time when the fish begins to grow rapidly—beginning the first week of May, 2015. The salmon performed well in our freshwater system, growing nearly a pound every month and with a 97 percent survival rate. Feed conversion was outstanding, as every ton of fish feed added produced nearly a ton of harvested salmon. Overall, fish welfare was excellent with no vaccination, disease outbreaks, sea lice, or toxic algae, all factors that can impact salmon farmed in ocean pens. Because of their excellent health, we used no pesticides or antibiotics. Salmon were continuously exercised at their optimum swimming speed (i.e., at or just below one body length per second), and water quality, particularly dissolved oxygen, was maintained at most advantageous levels throughout the production cycle.

The salmon produced were marketed at a mean size of 10-11 lbs. through seafood wholesaler JJ McDonnell, with many of the fish ending up at 14 Wegmans grocery stores in Maryland and Virginia for a limited time.  These salmon also met the Best Choice’ standards by Monterey Bay’s Seafood Watch program. A 6 oz fillet of these salmon contained approximately 220 mg of EPA and DHA (two types of Omega 3 fatty acids), as well as approximately 280 mg of total Omega 3 fatty acids, which is comparable or even greater than in wild salmon. Thus, just one 6 oz filet of this salmon comes close to meeting the suggested 250 mg guidelines for daily consumption of Omega-3 fatty acids.

Freshwater Institute salmon on ice Kata SharrerFreshwater Institute salmon harvested and ready for sale. Photo by Kata Sharrer.

By creating a sustainable non-fish meal feed, we are showing that it's possible to be both cost-competitive and good for the environment. The novel feed developed and information obtained through this practical and scientific study will assist with future decision-making by the entire North American salmon farming industry, government regulators, funders, and conservation advocates, resulting in better-informed decisions for future salmon feed and farming in Canada and the United States.

Fish-meal free feed is only one of the many novel ideas that will be discussed at the upcoming Aquaculture Innovation Workshop being held August 19-21, 2016 in Roanoke, Virginia. Aquaculture Innovation Workshop 2016 will attract a strong international audience and consist of invited presentations discussing the innovations and challenges surrounding food-fish production—particularly salmon and trout—in RAS. This conference provides an opportunity for aquaculture producers, scientists, engineers, aquaculture industry suppliers, regulators and investors to communicate progress on the technical, biological and economic feasibility of culturing fish to market size in land-based closed-containment systems using RAS technology.