This article was published in Frontline of Fisheries - March 2020
Fishmeal and fish oil are the starting points for formulating diets for farmed fish
As the fastest growing protein sector for more than 25 years, aquaculture remains one of the world’s most successful food producing industries as we move through the 21st century. According to the FAO, more than 44 million tonnes of fed farmed fish (including crustaceans and other fed aquatic species) was produced in 2018. According to the FAO, the rate of increase of aquaculture production remains high at 5.8% over the period 2001-2016, and it is interesting to note that the rate of increase of fed farmed production now outpaces non-fed aquaculture. There is a continuing need for aquafeed production in support of this growth.
China is the birthplace of modern global aquaculture and the Chinese people have been farming fish for more than twenty centuries. Farming units have changed markedly over that time of course, and it is only relatively recently that fed aquaculture production systems have developed into the systems that are so instantly recognisable these days. The industry we know in 2020 has developed only since the early 1970s, which explains partly the rate of development and the uptake of technology over time. The pioneering development of the sector in the early days was predicated on the ability to formulate nutritionally complete diets for the species being farmed, as is the maintenance of continual development. Early diets were produced predominantly from fishmeal and fish oil as this was a straightforward means of producing nutritious feeds. At that time, in the 1970s, most of the global fishmeal and fish oil production was directed towards pig and poultry feeds, and with aquaculture being a comparatively small, if emerging, industry the requirement for fishmeal and fish oil in terms of volume of supply was low.
Aquaculture has grown steadily and there has been much interest in aquatic animal protein production due to the relatively high efficiency of feed utilization. Feed is the major cost in aquaculture production, often accounting for 50-70% of total production costs (according to the FAO), so this is an important factor. Feed conversion ratios are the lowest of all farmed animals for the farmed fish species, i.e. the most efficient, as a reflection of their biology (cold-blooded) and their environment. This has driven development, and it is interesting to note that we are now in an age where those production efficiencies are increasingly under the microscope as the way we produce food is under more consideration in relation to the environmental impacts of production processes.
When we look at the volumes being produced there is an obvious mismatch in fishmeal and fish oil raw material supply for feed. The calculations for feed requirements are interesting. Currently more than 44 million tonnes of fed production, when considered at a relatively conservative FCR figure of 1.5, would require at least 66 million tonnes of aquafeed. At IFFO we estimate an annual year’s production of fishmeal and fish oil as being approximately 5 million tonnes of fishmeal and 1 million tonnes of fish oil. Not all the fishmeal and fish oil produced annually goes to aquaculture, and it takes about 70% of both materials, c. 3.5 million tonnes of fishmeal and 700,000 tonnes of fish oil. As feed materials, then, these are minor ingredients in terms of volume. They are, however, far from minor in terms of their nutritional value. They are essential.
Fishmeal and fish oil do in fact provide nutrition in the form of essential amino acids, and essential fatty acids. Although there are other sources of these materials, fishmeal and fish oil provide these compounds in profiles that directly reflect the diet of the farmed fish species in the wild, and are therefore immensely valuable. The essential amino acids are the constituent parts of proteins, and can become growth-limiting if they are present in the diet at levels below that required by the farmed fish for optimal growth. As other feed ingredients possess amino acids in different quantities and profiles, fishmeal is not directly replaceable, and feed formulators need to monitor amino acid content in their feed formulations accordingly. The same is true for the essential fatty acids, particularly so for the long chain omega-3 fatty acids, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA).
Fishmeal also possess a range of other important micronutrients in the form of vitamins (e.g. vitamin B12, vitamin D) and minerals (e.g. zinc, calcium, selenium). Again, some of these materials may be found in other feed ingredients, but fishmeal is a particularly rich source of many, and decreasing inclusion rates can mean that feed formulations require supplementation with specific additives. This can be costly for the feed producers. Fishmeal and fish oil are cost-effective and practical ways of providing good nutrition in aquafeeds.
All this nutrition that comes from fishmeal and fish oil is effectively extended by the use of other feed ingredients such as soya meal (often also soya protein concentrate), maize, wheat, rice, soya, and a range of other animal byproduct meals such as poultry byproduct meal, blood meal, and meat and bone meal. The fishmeal and fish oil are the starting points for formulating diets for farmed fish, and this is not likely to change for a very long time, if ever.
What this means in real terms is that those 3.5 million tonnes of fishmeal and 700,000 tonnes of fish oil (processed material into fed aquaculture) produces more than 44 million tonnes of fed farmed fish with the benefit of the additional ingredient supply. To put it another way, they produce more than 10 times their volume in farmed fish, an incredible multiplier effect, and one which illustrates the true importance of fishmeal and fish oil to global farmed seafood production. As the production of fed farmed fish is increasing year on year, whilst production of fishmeal and fish oil remains relatively flat, this multiplier effect is, in itself, continually increasing. These materials are the foundation of a modern global food industry, and society would struggle to make up that large volume of farmed protein without access to the materials.
In summary, fishmeal and fish oil are essential to the continued success of aquaculture development around the world. More feed ingredients are required to help support the continued need for feed volume increases, but the future for fishmeal and fish oil as key ingredients in aquafeeds is secure.
Dr Neil Auchterlonie
IFFO Technical Director