 Hi, I'm Marin and I'm a contributor here at Food Unfolded. I'm also a microbiologist, and I have a question for you. Did you know that aquaculture, or the farmed raising of aquatic animals for food, is the fastest growing food sector worldwide? It now surpasses wild caught fish as the main source of the world's seafood. The growth of this industry presents many environmental and ethical questions, but one of them is the use of antibiotics. What effect does the use of these drugs in aquaculture have on human health and the health of our oceans? Antibiotics are widely used in all kinds of agriculture, mostly in the farming of animals for meat production. And when I say antibiotics, what I mean is compounds that kill bacteria. Many of these are similar or even identical to what a doctor might prescribe you if you have a bacterial infection, and that's where the problems start. See, when fish live packed together in pens like this, all of their nutrients and waste are dispersed among all the animals, so it's really difficult to control an infection once it starts. In response, most aquaculture operations administer big doses of an antibiotic to the whole group of fish, not necessarily to treat the ones that are sick, but to protect those healthy fish until the sick ones die off. And because there's no way to make sure that every fish receives the same amount of antibiotics, some animals will receive large doses while some others will receive small doses. And in any situation where antibiotics are being used, but especially where they're being used irregularly within a population, we risk creating something called antibiotic resistance. Picture it like this. There are bacteria in the stomach of all of the fish in a pen, and some of these bacteria will have naturally developed genes that make them harder to kill with a certain kind of antibiotic. These are called antibiotic resistance genes. In a fish that consumed a small antibiotic dose, that dose may be enough to kill some of the bacteria living inside the fish, but not the ones that have evolved those resistance genes. So now all that's left in that fish are the resistant bacteria, and that antibiotic doesn't work in that fish anymore. And just to be clear, this happens not only in fish, but in other agriculture animals too, like shrimp. Now this obviously poses a problem for trying to keep fish healthy, but there's something really unique about bacteria that actually makes this everyone's problem. Because bacteria can trade genes back and forth, even across bacterial species. So say we treat a population of farmed fish with an antibiotic called ampicillin. Those fish bacteria may become resistant to ampicillin, but maybe they're not a kind of bacteria that can make humans sick. But if those fish bacteria come into contact with bacteria that do make humans sick, the fish bacteria could transfer their ampicillin resistance genes to those human bacteria. And ampicillin is a really important antibiotic that we use to treat serious human infections. So that's a problem. So how might that happen? Well, picture it like this. There's a whole big pen of fish with feed being tossed in by a farmer or a feed machine, and in that feed is antibiotic. Water from those pens will flow out into the surrounding environment, meaning that so does the antibiotic. Either in uneaten feed or in the animal's waste, antibiotic compounds do escape into the surrounding aquatic environment. And that's in addition to those antibiotic resistant bacteria themselves, which may have developed and replicated in the fish and found their way out into the environment too. And antibiotic resistant bacteria in the fish themselves may also come into contact with human pathogens during the harvesting, processing, packing, or shipping of that fish. And you as the direct consumer are actually at risk too in some cases. In foods that are eaten raw, like oysters, the bacteria that sometimes live in those oysters can make humans really sick. And if those bacteria have evolved antibiotic resistance, then you're in pretty big trouble because that's dangerous food poisoning that we can't treat. Antibiotic use in aquaculture doesn't just affect human health. It also has an effect on the environment itself, because the spread of antibiotics from the pens into the surrounding water can affect the diversity of microscopic organisms like phytoplankton and zooplankton, which are the key base of many wild aquatic food chains, meaning the effects of those antibiotics can radiate up into every level of the ecosystem. And they can also affect the health of other wild aquatic animals directly, maybe altering healthy gut microbiota, impairing their growth or suppressing their immune systems. So it's a big problem and one that affects all of us because our oceans are shared. So the solutions require global cooperation too. First of all, we need better data, and we need it from everyone currently practicing aquaculture. What kinds of antibiotics are being used? What kinds of antibiotic resistance genes are we seeing and in what bacteria? And how much antibiotic residue can we detect in the surrounding environment? That improved data can then be used to form evidence-based regulations for everyone to follow on when and how antibiotic use in aquaculture should be allowed, which will hopefully slow the development of antibiotic resistance and lessen the effect of antibiotic pollution. One of the central solutions that can be adopted by fisheries is not to use antibiotics preventatively. More holistic aquaculture practices that support the biodiversity of the surrounding ecosystem require good water filtration and improve fish health overall, or better solutions for preventing infection than applying antibiotics before you need them. It's always better to prevent disease than it is to have to treat it, and these methods make infections less likely in the first place, making sure we reserve antibiotics for emergency use only. Several countries have enacted measures like this in the past five years or so, and it's been shown to be effective not only for improving fish health, but reducing the prevalence of antibiotic resistance genes in those local bacterial populations. And research is coming up with exciting alternatives to antibiotics for treating disease once an infection has started. Things like probiotics or friendly bacteria that can fight off bad bacteria are a really promising solution to help us have to use antibiotics even less often. If you want to help reduce the impact that aquaculture has on our microbiological world, then you can support regulatory moves toward international standardization of antibiotic use in aquaculture. Because even if your own countries fisheries are in good health and have good regulations, your country may still import aquaculture products from countries where the oversight is not as strict, so global regulations put pressure on everyone to be safer. And if you want to keep all of this in mind while you're at the store, you can look for this logo from the Aquaculture Stewardship Council. The ASC is the world's leading certification and labeling program for responsible aquaculture, so if you see this logo, you can know that the farm this animal came from is actively minimizing their environmental impact, including following strict rules on antibiotic use. And if possible, you can think about reducing your consumption of fish products overall, which also reduces your carbon footprint.