Sustainable fish feeds
Aquaculture produces about half of the total fish production for human consumption. Aquaculture is, however, highly dependent upon marine capture fisheries for key dietary nutrients such as fish meal and fish oil. This dependency is particularly strong for farmed carnivorous fish species. Aquaculture is rapidly growing whereas the availability of fishmeal and fish oil for compound feed production is declining. As a consequence alternative ingredients like plant products and animal by-products are used to partially replace fish meal and fish oil. The production of fish meal and fish oil was about 5 and 1 million ton, respectively, in 1976. There was subsequently an increase in the production, but a decrease again to the same levels as 35 years ago. Fishmeal and fish oil is produced from reduction fish (about 75%), i.e. fish that is not suitable for human consumption and from trimmings and rejects from food fish (about 25%).
Most of the fish meal and fish oil is used for aquaculture, i.e. about 70% and 90%, respectively, in 2006. There has been a strong increase in the amount of fish meal and fish oil that is being used for aquaculture. This increase parallels the increase in aquaculture which is about 7% per year since 1976. The production of fish feeds also parallels the growth in aquaculture and was about 25 million tons in 2006, 4% of the total animal feed production worldwide. The prediction is that the production of fish feeds will increase to about 66 million ton in 2020. On the other hand, there is a trend that the production of fish meal and fish oil will not increase or even decrease. Thus, the inclusion of fish meal and fish oil in aqua feeds has to be lowered when this strong growth in aquaculture will continue.
Fish meal and fish oil are key ingredients for fish feeds. The degree of fish meal and fish oil dependency can be expressed in terms of dependency ratios. The dependency ratio of fish meal indicates how many kilograms of fish meal protein in the feed is used to generate 1 kg of protein in the fish. Net fish protein is generated when this ratio is smaller than 1. Similar dependency ratios are used the express the dependency of fish feeds on fish oil.
As a fish feed producer Coppens International bv invests, since many years, a large amount of its research budget in developing fish feeds with less fish meal and fish oil. This has already resulted in commercial diets that rely substantially less on marine ingredients and more on plant products and animal by-products even for carnivorous species. These alternative ingredients also offer the possibility to produce well performing feeds that still contain the essential nutrients, like long chain omega-3 fatty acids with their desired health benefits.
The graph shows the use of fish meal since 1995 and a prediction until 2020 for a typical diet used for trout (based on Tacon, 2008). Since 1995 the fish meal inclusion has been reduced by more than 50%. Further research is expected to enable another significant reduction by 2020. Coppens currently offers some trout feeds with which it is possible to be a net fish producer. Furthermore Coppens is currently testing the first trout diet without any fish meal at all. For carnivorous species like sea bass, who's natural diet is largely fish based, it will take more time and effort to reach this stage.
We should not forget that for omnivorous and herbivorous species like catfish, carp and tilapia Coppens currently already produces high performing diets with low amounts of fish meal and fish oil that allow for a very positive net fish production.
Fish oils contain the essential fish omega-3 fatty acids EPA and DHA and these acids are essential for the fish. Vegetable oils do not contain EPA and DHA and animal fats contain only very small amounts. Fish have a limited capability to synthesize these essential fatty acids and this capability is lower for marine and carnivorous fish than for fresh water and omnivorous and herbivorous fish. Thus, carnivorous fish are more dependent on fish oil than omnivorous and herbivorous fish. Depending on species Coppens is able to partially replace fish oil while still meeting the EPA and DHA requirements.
At the Coppens Research Centre (CRC) alternative ingredients are continuously examined. Coppens focuses its research on plant products and fish and animal by-products in order to fulfil the fish's requirements and further reduce fish meal and fish oil inclusion. Promising results have already been reached with extremely low levels of fish meal for several species. The end goal is to develop fish feeds that enable the net production for all species of farmed fish so that the pressure on marine resources is minimised and maximal sustainability is reached. The CRC is fully committed to make a significant contribution to this goal.