Is Aquaculture Sustainable? Mythbusting Feed, Food, and the Future

hello my name is Jessie darshan ski and I'm an associate professor with the Center for fisheries aquaculture and aquatic Sciences at Southern Illinois University Carbondale in this presentation I'm going to address the question is aquaculture sustainable my primary interest is in aquaculture feeds and fish nutrition but the issues of sustainability in aquaculture go well beyond feed much of what I hope to do is to correct misconceptions about aquaculture u.s. aquaculture in particular hence my subtitle myth-busting feed food and the future there is a lot of myths and disinformation in the media about aquaculture but my myth-busting efforts today will focus on four major themes we will begin by reminding ourselves of the challenge of seafood security and the mandate for aquaculture is one of the most important sources of protein now and in the future next we will begin to explore feeds and feeding practices addressing what actually goes into an aquaculture feed and the issues of feeding fish to fish finally we will discuss a number of topics related to health risks and benefits of eating farmed fish over the next 20 minutes or so I'm hoping you're going to be going over this calculation in your head trying to figure out whether it all adds up to aquaculture being a sustainable industry once we busted the myths and seen the facts I have no doubt that is how you will see things first let us recall the mandate for aquaculture the world is hungry and increasingly hungry for protein there are just over 7 billion of us on the planet at this time and over the next four decades or so it's estimated that our ranks will swell to more than 9.5 billion by the next century the human population will be nearly 11 billion strong based on population growth we will need to be producing 60% more food by 2050 not only will we need more food in general we will also need a lot more animal protein in particular increasing urbanization lower production costs greater buying power and the like have led to increases in total per capita consumption of animal protein whereas we need 60 percent more food by 2050 we need 60 percent more animal protein much sooner by 2030 seafood is an essential source of dietary protein and up until relatively recently almost all of it came from capture fisheries however since 1990s capture fishery landings have been relatively static 80 percent of fish stocks throughout the world are either fully exploited in other words they can't be fished any harder without negative consequences or they are in decline now the more optimistic of you might say well that means there's still another 20 percent that could be developed and that's true there's a reason these fisheries haven't been fully developed yet a good example would be the Antarctic krill fishery this fishery is under exploited because the fishing grounds are remote its logistical challenging fishing and the product which is not generally used for human consumption doesn't hold up well during the long trip back to port bottom line we are unlikely to get any more food from capture fisheries if anything in the future we may get less nonetheless seafood demand has continued to climb and aquaculture has grown dramatically over the past few decades to close this gap currently about half of the world's seafood does come from farms you may be saying yes well that's all very good an aquaculture is certainly important in the context of seafood supply but is it really important in the context of global protein supply well I doubt that any of you would consider cattle to be a minor contributor to global meat production so consider this farms now raise more seafood than beef not only does the aquaculture industry produce more meat than the cattle industry we do so more efficiently which brings us to our first element of sustainability feed conversion ratios feed conversion ratio is a measure of how efficiently an animal grows and is a simple ratio of the amount of feed offered to the amount of weight gained for swine the feed conversion ratio or FCR is usually about 3 3 pounds of feed for every 1 pound of gain for cattle it's about 8 to 1 and bear in mind this is for cattle on a feedlot yak the value is actually much higher for grass-fed beef poultry are substantially more efficient packing on a pound for every 2 pounds of feed they eat but fish because they do not expend energy to maintain their body temperatures are the most efficient capable of achieving one-to-one conversions not only do fish beat terrestrial livestock in terms of F CRS they also beat them in terms of dress out as much as 60% of a salmon carcass is edible whereas only about 40% of a steer is so our aquatic livestock gained weight more efficiently and more of what they gain can be directly translated to our dinner table in terms of doing more with less which is a key element of sustainability aquaculture is the most efficient means of transforming feed grade protein into food grade protein the efficiency of fish does come at a certain price however and this brings us to the challenges of feeding fish the aquaculture industry is staggeringly more diverse than any other form of livestock production poultry is probably the second most diverse and what do they raise chickens turkeys ducks geese beyond those first four it becomes a bit more difficult to think of what comes next in aquaculture more than 500 species are produced throughout the world including more than 300 fin fish running the gamut from omnivores like tilapia to mid-range carnivores like trout to apex predators like tuna not only does the species diversity make it challenging to identify demands and tolerances for all these different fish as we move along this spectrum the nutritional demands of fish increase making it more challenging to meet their demands in an economically and environmentally sustainable manner however it's important to recognize that even the species that we would consider to be easy keepers like tilapia are considerably more costly to feed than terrestrial livestock because they demand more protein and fat in their diet whereas protein makes up about a third or more of a tilapia diet it's only about 15 to 20 percent of poultry and swine diets so again the efficiency of fish is striking but fueling that efficient growth is not without its challenges with those challenges in mind what do we actually feed fish to provide them with the balance of protein lipid carbohydrate and micronutrients they need to grow and thrive well of course it depends on the species but we can generally categorize their feeds as being high energy for high-level carnivores medium energy for medium level carnivores or low energy for omnivores and herbivores although different fish have different demands their diets often contain the same ingredients albeit in different proportions because fish have such high protein demands their diets have to contain relatively protein bins ingredients usually if an ingredient has less than 20 to 30 percent protein it's not going to have much value in a typical aquaculture feed this is why aquaculture diets contain ingredients like fish meal soy products plant glutens and rendered animal products we also include various fats and oils to provide essential nutrients and energy proteins and lipids they are necessary to meet the demands of aquatic livestock but they also drive up the price of aquaculture feeds one of the major drivers of increasing feed cost is fish meal fish meal is a protein source that is derived from the so called reduction fisheries these are small marine pelagics such as anchovies and menhaden that are harvested and rendered into feed grade proteins and oils which have a variety of industrial and agricultural uses up until fairly recently fish meal is a very cost effective source of high quality protein it remains a highly nutritious ingredient but like other marine fisheries reduction fishery landings are largely static and as demand has increased the price has gone up I think it's important to note that while price is a problem it's not the only issue although we are increasingly using fish meal more judiciously aquaculture currently consumes about two-thirds of global fish meal production we need to produce more fish which means we are going to need more feed but we can't do that sustainably by commanding more and more of the fish meal market for all end-users of fish meal the problem in the future won't necessarily be its price but that there isn't enough to go around at any price the same is true of fish oil which also comes from the same reduction fisheries at this point the aquaculture industry uses about three-quarters of the available fish oil and so here again our industry faces a significant bottleneck now you may be thinking well this doesn't paint a particularly rosy picture of the aquaculture industry and to some extent that's true fish meal and fish oil are finite resources which our industry increasingly monopolizes when we talk about sustainability it's important to be earnest and to address these constraints directly this is a constraint but as we'll discuss in a few minutes it's one that's being addressed critics of aquaculture often latch on to the practice of feeding fish to fish and use cherry pick data sets to support their claim that the practice is unsustainable and that more fish go in than come out well this is a pretty easy myth to bust even if we were to assume that all the fish meal and fish oil in the world went into aqua feeds the aquaculture industry could hardly be considered a net consumer of fish globally reduction fishery landings total about 20 to 30 million metric tons per year whereas the aquaculture industry produces 60-some million metric tons per year you don't have to be a math whiz to sort out that this claim is just patently false it is however a persistent falsehood and is perpetuated by the misuse of so-called fish in fish out ratios as the name implies FIFO ratios describe the units of wild fish that are used in the form of fish meal and fish oil to produce one unit of farmed fish let's begin with one of the popular examples Atlantic salmon if you render a metric ton of sardines or anchovies you get about two hundred and twenty five kilos of fish meal and fifty kilos of fish oil if you use it to prepare a typical salmon diet containing 20% fish oil and 30% fish meal you can expect to raise about two hundred kilos of salmon 100 kilos in two hundred kilos out implies a FIFO ratio of five but this figure is misleading because what you actually get is 200 kilos of salmon plus 150 kilos of leftover fish meal the limiting resource in the case of salmon feed is the fish oil now let's look at a different example Pacific white leg shrimp if you used your fish meal and fish oil to make shrimp feed instead of salmon feed you can expect to raise about six hundred and sixty two kilos of shrimp now a FIFO ratio of 1.5 appears to be much better but this figure it also misleads what you really get is 662 kilos of shrimp plus 28 kilos of leftover fish oil you can probably guess where I'm going with this example what if we were to feed the Salmons leftover fish meal to the shrimp feed the shrimps leftover oil to the salmon and feed whatever tidbits are left to another species say a carp you end up getting a lot more fish out than the simplistic single species FIFO suggested and when you take global fish meal and fish oil usage and aquaculture production statistics into consideration the overall FIFO ratio is about 0.3 which means that for every pound of fish in you get 3 pounds of farmed fish out the aquaculture is contrary to what some might like you to believe a net producer of fish and might I add a producer of high-value seafood while we're on the topic of fish meal and fish oil usage I think it's important to recognize how much progress has been made regarding judicious use of marine resources these diagrams show the amount of fish in in red the amount of fish out and yellow and the FIFO ratio in the middle the more saturated colors are based on actual data whereas the lighter figures were predicted values two decades ago we were using a lot more fish meal and fish oil to produce aquaculture feeds but it was predicted that the industry's utilization of these resources would become more efficient take a look at the picture for 2015 we are already there as we have increased our understanding of fish's nutritional bow ponds what they need and what they tolerate we've improved feed formulations and have reached a FIFO of 0.3 ahead of schedule we can do more and we can improve our figures even further but is important to note that fish meal and fish oil will always be used in aquaculture and that's okay if the aquaculture industry didn't use fish meal and fish oil other industries would as we've seen they would not be able to use these ingredients to produce food as efficiently as the aquaculture industry does the key to sustainability is for our industry to use marine resources as judiciously as possible let's switch gears now and talk a bit about the sustainable production of healthy seafood another pervasive myth is that wild fish is better for you than farmed fish and provides more heart-healthy omega-3 fatty acids again in most cases this is simply not true wild salmon typically contains a higher percentage of long-chain omega-3s say 44 percent of the total in wild salmon compared to 30% in farmed salmon but wild salmon don't contain as much fat overall meaning that the total amount of long-chain omega-3s provided by a wild salmon in this example is only about a quarter of that provided by farm salmon remember people don't eat percentages they eat fillets and in terms of providing the most important farmed fish usually come out on top another pervasive myth is that while aquaculture may be efficient farm fish isn't safe unfortunately much of our environment has been contaminated as a result of human activity and both farmed and wild fish can contain heavy metals or persistent organic pollutants like PCBs however the benefits of consuming seafood greatly outweigh the risks that's not me saying that it's the National Academies Institute of Medicine the Food and Agriculture Organization and the World Health Organization there is no such thing as zero risk and it's true that if 100,000 people ate farmed salmon twice a week for 70 years 24 of them might die from PCB exposure related cancer but at least 7,000 more people would live because they made seafood and omega-3 fatty acids a part of their regular diet and avoided heart disease remember heart disease kills more Americans than cancer actually more than any other disease looking at these statistics the best risk management approach is obvious I'll also point out that most of the PCBs and dioxins we ingest in fact 90% of them don't come from seafood at all very very little of our per capita PCB intake is associated with farm fish most of it comes from beef and dairy neither of which provide long-chain omega-3s and there are no nutritional benefits this isn't to say that we shouldn't be concerned about contaminants in our food supply but I do believe we should examine this issue with the proper perspective the final myth I'd like to bust is that the aquaculture industry is reliant on antibiotics and foreign fish are riddled with antibiotic residues in the US all animal drugs including aquaculture drugs are regulated by the Food and Drug Administration or FDA before any animal drug is approved it must be proven effective and consistently manufactured and safe to the intended animal the environment and humans who might eat the animal it is perhaps the most rigorous drug approval process in the world and it is substantially more challenging to get a drug approved for fish than it is for other animals I would argue the drug approval process for aquaculture is in some ways more rigorous than the human drug approval process there are only eight drugs approved for use in u.s. aquaculture only the first three listed are actually antibiotics hydrogen peroxide formalin and chloramine tea are used essentially as sanitizing agents try cane methane sulfonate is a sedative used primarily by researchers and biologists for handling live fish and chorionic gonadotropin is used to help synchronize ovulation and broodstock not the fish that you eat as far as the antibiotics are concerned more floor fan Tikal is used in the beef industry than in fish and more oxytetracycline is used to prevent blemishes and Tomatoes than to treat diseases and fish sulfadimethoxine or meta prim is approved for use in fish but up until recently the manufacturer wasn't even making it available there simply wasn't enough demand from US aquaculture when any of these drugs are used it is only used to treat a disease unlike other livestock industries the u.s. aquaculture industry does not use antibiotics for growth promotion in other words antibiotic usage in u.s. aquaculture is very minor and the drugs used in u.s. aquaculture have been subjected to tremendous scrutiny to ensure that they have no negative effect on the farm fish their environment or the people who eat them to conclude I would argue that the aquaculture industry is sustainable it faces considerable myths and disinformation that would suggest otherwise but consider what we've discussed today aquaculture is the most efficient means of transforming feed grade protein into food grade protein and is a net producer of fish water usage is also efficient in aquaculture it actually takes more water to raise a pound of beef than to raise a pound of catfish u.s. aquaculture products are wholesome and nutritious they are not deficient in omega 3s or riddled with contaminants and antibiotic residues finally remember that the aquaculture industry is absolutely essential to global food security and feeding the billions of us that are here today and the billions more that will be here in the years to come with that thank you for your time and if you have questions please feel free to contact me via email or on my aquaculture theme blog factual fish squeezer


  1. Jackisath

    There's no science that says we need animal protein not funded by the industries themselves. Why would you think that we need animal protein?

  2. jenniffer hurtado

    the greatest results that ive had was by using the Keiths Ponics Site (just google it) without a doubt the best info that I have ever tried.

  3. silverleapers

    What biased, garbage stats, propaganda. Sausage like fake fish, toxins and pollution, and disease are the results among other nightmares. Get real.

  4. Ally Harris

    It sounds good that the US prohibits use of antibiotics as growth promoters, but don't we also import most of the farmed fish we eat?

  5. Kamal Hossain

    thanks a lot for your great & true scientific research and informations. I want to start my own Aquaculture project, If you help me I will be great full to you. .1. Which fish is best for aquaculture system?
    2. The ratio of fishes?
    3. Water level & percentage of O2?
    4 . For air circulation system which system is best?
    5. The average temperature of water?
    6.The amount of protein in fish meal?
    7. Which elements is best for fish meal? (rice, wheat, popcorn, soyabin. ..etc )
    8.Is it necessary to cover the fish pond?
    9.Is it possible to produce 1 kg fish by using 1 kg fish meal?
    10 . Which pond size is best for aquaculture (wide & length ) .
    Please help me to achieve my ambition & fulfill my hobby.


    hi everyone ,if anyone else wants to uncover aquaponic gardening system try Panlarko Expert Aquaponics Planner (just google it ) ? Ive heard some interesting things about it and my colleague got amazing success with it.

  7. I hate this Google+ Shit

    Great video. I am considering using it for a class presentation.
    I have a question. You talk about sustainability and food conversion ratios. It is my understanding that the fish grow efficiently because their environment is set to optimal growing conditions. So, what is the energy cost of aquaculture (i.e providing the right environmental conditions) compared to other protein sources?

  8. Darth Belal

    I'd love to see even more innovation in aquaculture and more growth.  The way I see it, IF the fish are grown in controlled, clean conditions and are available locally, one would get a fresher and more consistent product without damaging wild fish stocks.

    It would be nice if one could go to an aquaculture market the way we go to farmer's market to get the freshest fish, shrimp, prawns and crabs.  THAT would be wonderful.


Leave a Comment

Your email address will not be published. Required fields are marked *