By Brittany Peachey
Imagine you’ve been tasked with developing a fish farm on a distant planet. The conditions outside your biosphere are harsh, unforgiving, and ever-changing. You’ve got access to water, but not much, and the quality of it is suspect due to unknown organisms lurking within. What inputs and outputs would you need to consider and plan for? How would you ensure the water was used wisely and your animals were healthy and productive?
How do we produce high-quality, safe, and healthy fish without harming our environment in a world with finite resources and fluctuating conditions? While our situation isn’t quite as dramatic as a space agricultural mission to a hostile planet, it’s fun to think of our recirculating aquaculture system (RAS) farm in these terms. RAS fish farms are a relatively new development in the aquaculture industry that are just beginning to expand in the US and across the globe.
RAS farms have several advantages over more conventional methods of fish farming and wild capture fisheries. Referring back to the space illustration, keeping unwanted organisms out of your biosphere will protect against disease coming into your environment. Regardless of the water source, RAS farms can disinfect the water before it is used in fish production. Bacteria, viruses, and parasites that may be present in the water from wild fish cannot enter the farm. Our farm uses groundwater and is also contained within a building, which prevents disease transfer from wild vectors, such as fish, birds, insects, etc., and stops predation from without, meaning lethal force on predators is unnecessary. Biosecurity extends beyond the water to other inputs in the farm, including fish, equipment, personnel, and feed. Our strict biosecurity protocols in these areas and our isolation from the environment mean that we do not need to use antibiotics to treat our fish, nor do we use hormones in an attempt to achieve faster growth. The benefit of isolation goes both ways and protects wild fish populations by isolating them from our fish. Unlike open water farms, the risk of fish escaping from our farm to a natural water body is essentially zero. Concerns about disease and genetic material transfer between wild trout and our farmed trout are answered.
Another benefit of RAS farms is the control of the production environment. Due to our system control (water quality, O2 levels, temperature), we produce steelhead trout year-round without seasonal fluctuations in the outside environment. We don’t need to worry about environmental threats such as algae blooms, sea lice, and jellyfish attacks, as has been recently seen in the Norwegian salmon industry. System parameters are fine-tuned to provide for the best possible fish health and growth environment. Each RAS at Hudson Valley Fisheries has its own set of filters, involving mechanical filtration for solids, biofiltration for nitrogenous wastes, and aeration filtration for respiratory waste. Using these filters, we can reuse our precious water inputs many times before discharge.
Considering farm inputs, a question we often get is, “What is the fish feed made of?” With limited resources available to the biosphere and maintenance of water quality being necessary, we must weigh our options carefully. In the past, aquaculture relied heavily on lower-value wild capture fisheries to make fish meals and fish oil for higher-value species, such as salmon. While these ingredients are still used, their proportion in the feed is greatly reduced from the historic highs seen in the 1980s. Our fish feed includes some marine ingredients, but most are plant-based and non-GMO. We constantly look for alternative sustainable feed ingredients, such as microalgae-based products, to improve our sustainability practices. According to some current trials, algae products appear to be a nutritious and sustainable replacement for some marine ingredients. Other new ingredients, such as insect-based products, also show promise; once they prove efficacious, we’ll give them a go.
The overarching goal is to reduce marine-based ingredients in fish feed to alleviate pressure on wild capture fisheries of species such as herring, anchovies, and menhaden. The fisheries that are harvested for use in our fish feed are subject to third-party verification for sustainable practices through the Best Aquaculture Practices Certification (more on that later). So, why feed wild fish to farmed fish at all? The answer is fish health and welfare. We’re growing a carnivorous species, trout. While there has been a lot of good research on growing trout with a fully plant-based diet, in my opinion, the feed nutritional technology is not quite there yet. Fully plant-based diets can cause gastrointestinal upset and poor digestion in trout, compromising their welfare and health as well as affecting water quality.
Let’s talk about fish poop. Due to our recirculating systems, healthy and efficient digestion of the feed is absolutely necessary to maintain water quality and filter productivity. Fish feed needs to be digested fully in the gut to remove all needed nutrients for the fish and so that those nutrients are not dissolved in the water. Furthermore, the feces generated need to be compact and not diffuse so that mechanical filtration can remove them promptly. Gastrointestinal distress (aka diarrhea) in fish must be avoided for both fish and system health.
Unlike most open-water aquaculture, capturing our waste outputs is an important part of our process; we consider these a valuable resource. We have a wastewater treatment plant that captures and separates solids (feces, uneaten feed), diverting them to dewatering and, eventually, a composting facility. The small amount of outgoing water is treated to high standards set by NY DEC and Best Aquaculture Practices (BAP) before discharge, with a side stream being used for plant production.
Speaking of high standards, Hudson Valley Fisheries is the only RAS farm in the world to have achieved 4-star BAP Certification. BAP Certification addresses environmental stewardship, social accountability, fish health and welfare, and food safety and traceability. These standards are applied across four sectors of the production cycle: feed mill, hatchery, farm, and processing plant. As mentioned, our feed suppliers submit to this third-party verification to ensure that our feed is produced and handled responsibly. Hudson Valley Fisheries has a distinct advantage over the other sectors because we hatch, raise, harvest, and process our fish on-site here in Hudson, NY. Our on-site harvesting and processing mean that we can trace the history and track the destination of each fish we sell. Why is this important? The seafood supply chain is convoluted at best; approximately 90% of seafood consumed in the US is imported. With the many hands that touch imported seafood, it’s easy for fish fraud to occur. There have been, in the past, and there will be, in the future, bad actors who attempt to bamboozle customers by calling catfish fillets grouper, for example. Our customers can enjoy their meals knowing where their fish are from, how they were raised, and that best practices were used throughout the entire process.
This highlights another benefit that Hudson Valley Fisheries has – our location. We’re within a two-hour drive of NYC and close to many major markets in the Northeast. Compare the emissions of trucking our fish to local markets to the air freight emissions cost of flying salmon or trout from Norway, Scotland, or Chile. Add to this consideration freshness. It’s possible to get a fish from our farm to a local customer within hours of harvest, compared to days or weeks for fresh and frozen fish shipped from overseas.
Our trout comes from certified specific disease-free stocks in the United States. Their genetic lines have been domesticated and refined over the last 79 years. We continue to work with our egg suppliers to improve the genetics of their stocks and suit them to our distinct environment, maximizing healthy growth. The fish we grow in our systems are our most important input.
We receive our fish as eyed eggs, meaning that they are fertilized and their eyes have developed but still have some to grow more before hatching. When they arrive at the farm, we disinfect them. During incubation, which also acts as quarantine, the fish hatch into alevins and finally develop into fry. Once they’re eating our high-quality feeds, their growth really takes off. Through every stage of growth and transfer from system to system, excellent fish health and welfare is the goal. Even as we harvest the fish, we do it in a way that reduces stress on the animal. Our electrostunning system ensures that the fish are insensitive to stimuli before they are dispatched. This is the gold standard of fish harvest and indeed, provides a better product to the consumer as well.
Providing fresh, safe, healthy, and nutritious fish to the local community is an essential motivator for me. Good food is a form of love: love for your body, your family, and your friends. It brings me joy to know that many people enjoy the fruits of our labors here at Hudson Valley Fisheries, for they are truly labors of love.
Brittany Peachey is Aquaculture Operations Manager at Hudson Valley Fish Farm, a land-based recirculating aquaculture system in Hudson, New York, and a 2020 recipient of Hatchery International's Top 10 Under 40.
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