In my first post, I wrote about the importance of fisheries for feed. In this article, I’m going to get into the main form that these fisheries occur and that is something called reduction fisheries. Reduction fisheries are fisheries for the purpose of the production of two products: fishmeal and fish oil. Fishmeal and fish oil are essentially the stabilized product form of fish protein and fish fats, respectively. They are called reduction fisheries because they ‘reduce’ whole fish to their component parts of fat and protein. This is the main form of fishing for feed, currently consisting of 75% of capture fisheries destined for non-human consumption uses (I’ll get into details on this in a later post). Reduction fisheries are those fisheries that are specifically for this product, and are not directed for human consumption.
As I mentioned, fishmeal and fish oil are the stable forms of these fish proteins and fats. This is important because fisheries are often seasonal depending on the abundance of the fish in the water, and this takes a seasonal product and turns it into something that is stable for a longer time. This occurs through processing of whole fish.
Fishmeal and fish oil are processed through essentially squeezing and cooking the fish (details can be found in this old UN Food and Agriculture Organization report). The squeezing presses the fats out the fish and is collected as fish oil, a valuable product for fish needing fatty diets (think salmon). There is a growing market for fish oil for human consumption, mainly in the form of Omega-3 supplements.
Fishmeal on the other hand is the dried powder of fish once almost all the water has essentially been cooked out of it. Fishmeal is a complete protein (contains all amino acids) and thus is very effective as a supplement to livestock diets, and contains some amino acids that are rarely available from other sources. The quality of the protein in fishmeal is what makes it such an almost necessary ingredient to livestock production, and specifically aquaculture of piscivorous fish (fish-eating fish like salmon and tuna). However, even fish that are naturally herbivorous or omnivorous like various species of carps can benefit significantly in how fast they can be grown from supplements of fishmeal to their diets.
Separate from reduction fisheries, fishmeal and fish oil are often made from by-products of processing fish for human consumption (you don’t see a lot of fish carcasses in the grocery stores but you do see a lot of filets). This takes something that might be wasted and turns it into a product that is useful for livestock and aquaculture, although the protein quality is often less than that of fishmeal from reduction fisheries.
Getting back to the fishery though, reduction fisheries are often (not always though!) targeting small schooling surface dwelling fish (AKA small pelagics). Common fish include various species of anchovies, sardines, herring, and menhadens. The schooling behaviour of these fish, and that they are often very numerous make these fisheries very efficient in getting them out of the water, and they can use gears that often don’t negatively affect other sea-life. The scale of these fisheries however can lead to overexploitation of the fish, which can lead to long-term collapses of population. In addition, these fish populations fluctuate with the productivity of the organisms below them on the food chain. These two factors can complicate management as its easy to fish a lot of these folks, and their population can fluctuate wildly based on climate and productivity of the ecosystem.
Reduction fisheries are the main vehicles for the production of fishmeal and fish oil, and fishmeal and fish oil are the main ways that fish are used for feed. This makes them very important to my research on how we use fish for feed and for food. They make up a huge portion of total capture fisheries, and are some of the largest fisheries in the world. And most importantly, if you eaten fish, pig, or chicken in the last few years, you’ve likely indirectly consumed some or a lot of these fish. Given that these fish are an important input into so many food production systems, we need to understand these fisheries impacts on their ecosystems, the people who fish, feed, and eat them, and the planet.