Why Farm Fish?

To understand why we should farm fish we must first consider the significance of agriculture in the modern world. The development of agriculture occurred around 13,000 years ago, initially farming grains, fruits, and mammals [1]. Farming led to a profound change in mankind’s pace of technological development and quality of life. Suddenly humans no longer had to live life as wanderers; foraging for food, living in mobile villages, and suffering when Mother Nature did not provide adequate food. As we settled into an agrarian lifestyle we improved our techniques for growing food. By domesticating plant and animal species we increased yields and enjoyed a higher quality of life. Yet since the invention of farming nearly 13,000 years ago man has continued to forage on one final frontier, the ocean.

Although aquaculture, the farming of fish, shellfish and algae, was first practiced 2,500 years ago in China, it has never been the method of choice to obtain fish [2]. Instead we fished, and for many years the ocean was able to provide us with ample food while tempering our growing hunting ambitions with its size and depth. However, as time went by, we developed new technologies for fishing, such as diesel ships, dredge nets, and refrigeration. Suddenly the ocean was no longer such a big place and we reached a point like we did on land thousands of years ago where wild stocks could no longer meet our demand. Ninety percent of wild fish stocks are now fully exploited or overexploited and our fishing has had a strong effect on the ocean ecosystem [3]. Just as we decimated many large mammal populations thousands of years ago, we are now on the path to sending sharks, tunas, and many other fish species into extinction. Farming is an important conservation tool for our oceans and it has the added benefit of being able to raise the standard of living for millions of people who rely on fish as the main form of protein in their diets. As the world population grows we need to find more ways to utilize our oceans and inland bodies of water for food production while limiting our reliance on wild fish.

Fish account for 17% of worldwide animal protein consumption and per capita consumption has nearly doubled over the past fifty years to 19.7 kg/person in 2013 [4]. Seafood is an important part of international trade, and an important source of income for many developing countries such as Vietnam, Indonesia, and India. Many countries also have considerable seafood trade deficits; for instance in the United States 90% of seafood is imported, around $14 billion worth of seafood, half of which is from aquaculture [5]. In 2014, 44% of worldwide seafood products came from aquaculture and 56% came from wild fisheries, a total of 160 million tons of fish [6]. In the past 50 years the aquaculture industry has grown at an average rate of 8% a year. In recent years aquaculture’s share of fish production has grown dramatically, rising in value from $40 billion in 1995 to $160 billion in 2014 [7]. Fortunately, these trends indicate we are in a good position today to continue the transition to farming seafood instead of foraging. Humankind’s future challenge is to figure out how we can continue to sustainably increase our seafood production to meet a growing global population that is increasingly choosing fish protein over other foods.

Production of aquaculture and capture fisheries over the past 64 years (Source: FAO 2016).

Aquaculture is a catchall term describing the practice of growing and harvesting a diverse assortment of aquatic animal and plant species. In total, approximately 560 species of aquatic plants and animals are farmed worldwide, with 10% of those species accounting for the vast majority of production [8]. Commonly cultured organisms include Atlantic salmon, trout, tilapia, catfish, carp, oysters, clams, mussels, and shrimp. Common freshwater aquaculture methods include ponds, raceways, and net pens, located in both rivers and lakes. Freshwater aquaculture production is dominated by carp ponds, most of which is produced and sold in China. Seawater methods include net pens, shellfish beds, shellfish rafts, and seaweed line culture. Land-based tanks and recirculating aquaculture systems are recently becoming economically viable and can be operated with either freshwater or saltwater. In the future, all of these aquaculture practices will be need to be modernized and expanded to increase fish production.

All food production has an impact on the environment, this includes both wild-caught and farmed fish, vegetables and fruit. The conscientious consumer already knows the environmental costs of beef production; the water, fuel, and feed to produce a pound of beef are all high relative to other forms of food production. However, it is also important to realize that when you drink a glass of cold orange juice, not only was there carbon dioxide produced during the harvest and shipping of the product, but the field where those oranges were grown in Florida were once a subtropical forest full of birds, reptiles, and insects. Similarly, the wheat in your morning toast was grown on what was previously prairie land, full of natural grasses. And finally the raspberry jam that you are putting on your toast may have come from a field in the Northwest United States that once supported old growth forests. These land-based ecosystems were once impacted by the introduction of farming, yet we seem to give these forms of agriculture a free pass while holding aquaculture to a higher standard. The only difference is 100 years ago we did not have environmental scientists arguing the merits of keeping wild ecosystems intact, we were instead focused on feeding millions of people. It is impossible to farm something without impacting the environment, the question is instead what are the benefits and drawbacks, and what as a society are we willing to accept, based on our needs. Turning tidelands into oyster beds does affect the crabs, fish, seals and other creatures that call that area home, but is it worth it to produce a healthy food? Many articles have been published online and in print posing the question “Is aquaculture bad for the environment?” And it is a good question, but it is only fair to ask this same question about all of our farmed food, because under strict environmental standards the answer will always be yes.

Advantages

First lets discuss the advantages of aquaculture as compared to traditional land-based agriculture, particularly meat production. Compared to beef, pork, or chicken fish contains high levels of DHA and EPA fatty acids, two of the three omega fatty acids chains that along with ALA t are vital to human physiological well being [9]. These fatty acids are initially synthesized by phytoplankton, the base of nearly all aquatic food webs, and these nutrients move up the food web until they are eventually consumed by fish. In addition to omega-3’s fish also contain other important dietary fats and proteins. As a result fish and shellfish are generally considered an important piece of a healthy diet. The nutritional benefits of consuming fish have led to increased demand in both developed and developing countries.

There are a couple of other unique advantages to aquaculture as compared to traditional agriculture; first is the ability to farm in a three dimensional environment. In other words, you can farm vertically allowing for a greater production in a smaller footprint. A good example of this is how mussels can be farmed on 60 foot long ropes that extend downwards from a raft on the surface. Aquaculture species are cold blooded which means they do not expend energy to keep their bodies warm. They also live in a “zero-gravity” environment, where they do not expend energy to stay upright or fight gravity. These energy savings allow fish to grow very efficiently; a greater share of the total ingested energy is spent on directly on growth as compared to land animals.

Farmed abalone, the shell color bands reflect the seaweed varieties eaten during various life stages.

Aquaculture offers many advantages over all traditional fisheries the foremost being the ability to provide fresh, consistent supply of fish year-round. Traditional fisheries rely on the seasonality of fish movements, breeding cycles, and weather conditions to determine when fish are caught. Consumers, through grocery stores and restaurants, have a year round demand for seafood. This is best met by a source that can supply fish year-round. The Alaskan salmon industry is a great example of a seasonal fishery that cannot supply fresh fish at all times of the year. To meet demand, fillets are initially frozen and later thawed and sold, or salmon is sent directly to a cannery and sold as a less desirable/valuable product. Year-to-year changes in harvests pose a similar challenge for many fisheries. Weather conditions, predator-prey relationships, and past fishing pressure all determine whether a particular fishing season will be a good one or bad one. As a result, the supply differs year to year and thus the price of fish varies based on whims of Mother Nature. Price inconsistencies discourage consumers from choosing fish over other sources of protein since its availability and price is ever-changing. In addition, fishing fleets often sit idle for a good part of the year, waiting for the fishing season to open, and when it does, there is no guarantee that there will be enough fish that year to sustain their business and pay their employee’s wages. In bad years the government sometimes has to step in with subsidies to prop up the industry for another season. Aquaculture is not beholden to many of these pitfalls since a well-managed farm can ensure a steady supply of market ready fish.

Overfishing is also a growing concern in nearly all the world’s fisheries. As demand continues to outstrip supply, prices increase and the pressure on an already dangerously low fish population is heightened. Government employed fishery managers are responsible for walking a tight rope between allowing fisherman to harvest enough fish to keep the industry alive, while leaving enough fish behind to allow for a sustainable harvest in the years to come. In order to accomplish this, fishery managers rely on complicated sets of rules and regulations to create artificial barriers to easily catching fish. Rules range from time limits, gear restrictions, to harvest quotas. All of these rules require enforcement and they change from species to species, country to country and year to year. These rules only apply where countries have jurisdiction, typically in their economic exclusive zones (EEZ), which reach 200 miles offshore. Beyond those limits, in the high seas, fishermen face fewer rules and less scrutiny. International treaties and agreements attempt to manage the fisheries beyond individual government jurisdictions, but enforcement is difficult and overfishing can still occur. The collapsing Pacific and Atlantic Bluefin tuna fisheries are good examples of the difficulty of managing the stock of a species that roams between dozens of countries.

A final issue with traditional fisheries is their distance from potential markets. Many fish are caught in remote areas off the coasts of countries that can be thousands of miles away from the final consumer. Aquaculture products can be grown inside cities or at the very least within a reasonable distance to a daily delivery route. The advantages of aquaculture make it an attractive business opportunity, and by consuming aquaculture fish protein we can decrease our environmental footprint while improving our health.

Drawbacks

Although the purpose of this essay is to serve as a booster for fish farming it be would disingenuous to not address the disadvantages of aquaculture. It is possible for technological advancements to solve many of these problems, along with government and consumer oversight to limit destructive practices. First let’s address fish poop; the flushing and removal of fecal matter from the same water that a fish also uses to breathe is a major challenge for all forms of aquaculture. In the ocean this fecal matter can naturally build up on the ocean floor. Similarly, in pond or raceway systems fecal matter is flushed into natural bodies of water. Often times this pollution is not treated in anyway but is instead diluted into a large body of water where its concentration eventually becomes negligible. This is not a sustainable solution and the good news is we can limit fecal pollution with settling ponds, screens, or by regularly moving the farm sites. When captured the feces can serve as a great fertilizer for crops. And in the ocean, benthic habitat can recover in 12 months, a lot faster than a forest or grassland would if disturbed.

Another concern is the possibility of farmed fish escaping from farms and entering the oceans. This is a big problem if farmers are careless and it can lead to the proliferation of invasive species or new diseases. The only way to limit these problems is through regulation and the personal accountability of farmers. One solution is the use of closed-containment land-based systems; which will be discussed further in this essay, these systems make escape or disease movement nearly impossible.

Another major concern is the use of antibiotics to improve fish health. Antibiotic use is now strictly controlled now in most of the developed world, and a good farmer does not need to use antibiotics to control diseases. The developing world still needs to address how they can curtail antibiotic use.

One of the major drawbacks of feeding fish in farms is that wild fish is an important component in nearly all aquaculture feeds, it is most similar to what a fish would eat in the wild and it provides crucial fatty acids and amino acids. The fish that is often used for this is anchovies or other non-food fish and/or fish trimmings. New fish feed formulations limit the amount of wild fish, since it is expensive and its inclusion is not sustainable as the industry grows. Most farms now produce 1 lb. of fish for every 1 lb. of feed, this is known as the feed conversion ration (FCR). One advantage of this practice is that non-palatable wild fish is converted into marketable farmed fish products.

Finally, farming fish leads to the erosion of the traditional fishing industry. Fisherman have to compete with fish farmers for market share, and in many places the costs of catching fish is no longer justified by the price for which it can be sold. This loss of income can be devastating to some coastal communities, but it is unfortunately the cost of technological development and a changing world. Government programs are now available in some Canadian and Northeastern US towns that retrain fisherman to become shellfish farmers. This is a step in the right direction. Together all of the drawbacks can make aquaculture seem like a bad deal, but the advantages to the environment and to consumers outweigh these costs.

Challenges

Despite the advantages of aquaculture, there are a few of challenges that first need to be addressed before we can ramp up production and end our dependence on wild fish. In developed countries, government regulations create an extremely high barrier to entry. This is particularly true in the United States, where lawmakers have not taken the initiative to streamline the cumbersome environmental review processes. In order to build a farm off the coast of many areas of the United States, a farm must first receive approval from nearly 40 organizations and agencies, any one of whom could derail the project indefinitely. There are multiple agencies at each level of government, local, state, and federal, creating a bureaucratic challenge for new farming entrepreneurs. Navigating this process can take millions of dollars and multiple years. As a result, only a couple of businesses are currently trying to launch offshore aquaculture projects in the United States. Permitting on-land farms can be comparably difficult. Obtaining the proper waste discharge and fish-handling permits takes time and money. Certainly, all new operations should perform their environmental due diligence and the government needs to provide proper oversight, enforcing laws and regulations. However, a faster decision making process, and the inclusion of knowledgeable individuals to guide farmers through the process would go along way towards getting more farms off the ground. Currently the lack of knowledge around aquaculture among regulators seems to slow new projects to a stop, no one person is willing to take the responsibility for green lighting a prospective project and therefore nothing moves forward. In some cases it seems regulators have tried to delay the approval process for so long that the applicant simply gives up in despair, preventing the government from having to shoulder any responsibility in making a definitive decision to permit a new farm. Individuals inside and outside of the government need to take responsibility; there needs to be a call to action to make the permitting process much easier, this challenge is technically very easy to overcome with political willpower.

Large sturgeon grown for caviar production in tank-based systems.

The next most pressing challenge for aquaculture today is a lack of positive public perception. Aquaculture has been incorrectly branded as bad for the environment and bad for human health. It has been juxtaposed against wild fisheries, which are framed as the better option for consumers. Nonetheless, the current public opinion seems to hold products perceived as natural in higher regard, and artificial in lower regard, no matter the context or evidence to the contrary. Aquaculture also suffers from over-generalizations by the public, therefore bad practices and actors are shown to be representative of the industry as a whole. We know there are environmentally responsible ways to do aquaculture. In the past ten years aquaculture has seen progress in its public perception, but there is still room to grow. And it is unfair to hold up wild fisheries as the good choice when often times they are equally or more damaging to the environment. The Monterrey Bay aquarium Seafood Watch program has undoubtedly had the most impact in shaping public perception around the sustainability of wild and farmed fish. The aquarium publishes a small guide for consumers to consult during restaurant visits or grocery trips, fish are divided into three categories “best choice”, “good alternatives” and “avoid”. They have wild and farmed fish in both their “best choice” and “avoid” categories, demonstrating that no clear lines can be drawn. The perception that some farmed fish are poor for your health is more difficult to battle since there is no evidence to support either side. The fact is that all fish are healthier for both you and the environment compared to other animal based proteins. In addition, if the price, variety, and availability of fish are all improved, then public health will improve as well.

Another challenge facing the aquaculture industry is the large number of species that are consumed, thus fracturing the market. Different countries and even different US states prefer different fish species. This preference makes seafood unlike any other major animal proteins. Beef, pork, chicken, duck, turkey, goat, and mutton, are almost all universally consumed across a variety of markets. Seafood preference is very regional, where each culture enjoys traditional dishes made with specific fish species that they are accustomed to consuming. These preferences were originally based on which fish were available nearby. A modern advantage of farmed fish is that the same species can now be grown in many locations and distributed worldwide. The wide array of species preferences and hyper-regionality is an obstacle that will likely dissolve with time. Salmon, trout, shrimp and tilapia are becoming frequently cultured and sold in markets all over the world. In time, it is likely that a few species will rise to dominate the industry and be available all over the world. This will allow businesses to take advantage of scales of efficiencies in producing fish, similar to what chicken or beef farmers have been able to do over previous decades.

Opportunities

The aquaculture industry has multiple opportunities to capitalize on the growing worldwide demand of the next decade. This growing demand is being driven by increased consumer acceptance, lower prices, health benefits, and population growth. In addition to a budding market there are promising upcoming developments in aquaculture technology that will increase profitability. One of the benefits of aquaculture being a late bloomer in the agriculture world is the ability to learn from existing industries and to look towards conventional agriculture practices to avoid past pitfalls. Aquaculture sectors that are currently being developed and improved include feed formulation, genetic optimization, production science, and disease management.

Feed formulation advances are moving us towards a fishmeal-free future. Fish feeds are composed primarily of fats and proteins derived from various sources. Developing a feed with the correct protein and fat profile is most easily accomplished by using fishmeal and fish oil, essentially the same ingredients that a fish would feed on in their natural environment. Using other sources of protein such as soybean isolate, and fats such as canola oil requires the addition of vitamins and nutrients. As we learn more about the dietary needs of fish, these alternative feeds are becoming more realistic. Algae may be the protein and fat source for farmed fish going forward, as commercial algae growers ramp up production and algae products fall in price. Algae is the base ingredient of nearly all aquatic food webs and it works well in fish feeds. Similarly, insects, specifically mealworms and solider fly larvae, have the potential to be the fish food of the future. These grubs feed on food waste and they grow quickly and essentially turn the food waste into good quality proteins and fats. New fish feeds will be tailored to specific species and life stages, perhaps eventually even allowing for the tuning of the fish’s exact fat content and potentially the meats flavor profile. Large multinational agriculture feed companies such as Cargill and Nutreco have taken an interest in fish feed and are investing in research to further develop these technologies. Feed advances will lower the cost of raising fish while making it more environmentally sustainable and scalable.

Given the relative adolescence of the aquaculture industry, the potential for genetic manipulation of commonly cultured species has not been fully realized. Generations of chickens, pigs, and cattle were bred for decades to create the genetic lines that are used across the world today. Domestication, or the act of breeding a species to increase productivity, has led to huge leaps of efficiency in the poultry industry [10]. Chickens now grow three times larger in half the time as they did only 30 years ago. Similar advances need to occur in the aquaculture industry to increases its profitability and production. Large multinational companies like Hendrix Genetics are now beginning to breed oysters, trout, salmon, tilapia, barramundi, sea bream, catfish, and other species to create distinct genetic lines that can be marketed and sold to farmers. Continued breeding will lead to strains that are more disease resistant, faster growing, and even more aesthetically pleasing to the benefit of the consumer. However, it may take a decade before their efforts begin to pay off. It is possible that a few of species of fish and shellfish will become the most popular and evolve into worldwide commodities much like pork and beef are today. Atlantic salmon is the closest to reaching this status and it is likely other species will follow its model. Fish breeding is not as straightforward as mammal breeding, but similar results can be easily accomplished with modern day genetic analysis. Advanced genetic techniques combined with new investment will lead to the rapid development of new and improved fish strains.

Recirculating aquaculture system (RAS) water treatment flow chart.

Currently, new aquaculture production methods are being researched and commercialized which ultimately will reduce the environmental impact while improving farming efficiency. One example is land-based recirculating aquaculture systems (RAS), which use significantly less water than traditional aquaculture systems and discharge minimal waste. RAS are typically housed inside of buildings where the environment can be carefully controlled to suit the fish. Similarly, the farm can be situated near large urban areas where the fish is consumed, reducing transportation costs and increasing freshness. The tank-based systems have the potential to produce high protein products in places where these nutrients are needed. By functioning as a closed-loop system the natural environment is not harmed in any way and waste can be repurposed or recycled. Systems like these have the opportunity to make farming cheaper and more sustainable. All of these technical developments will take time and will involve cooperation between government researchers and private industry.

Conclusion

The development of agriculture is one of mankind’s crowning achievements and the methods we use to produce food are still improving. Aquaculture is the next step in a long and rich history of finding ways to produce food with less effort and expense. Aquaculture has the opportunity to not only feed more people but to also stop further environmental destruction and the depletion of wild fish stocks. The aquaculture industry will not change overnight, but slow steady progress will allow humankind to reduce its reliance on wild-caught fish. The world’s ocean and land provide ample space to perform environmentally sustainable aquaculture that produces high-quality, healthy food for generations. All agriculture has a strong economic multiplier, whereby one dollar generated by the industry leads to at least one more dollar being generated in the community. The environmental and business advantages of aquaculture are too great to ignore, increased investment in the industry is already occurring and growth has been taking place for the past 40 years. Further development will only move faster as more business leaders and consumers embrace aquaculture. The future of fish depends on the future of aquaculture; lets make sure we don’t all miss the boat. Let’s farm fish!