Demonstration of salmon farming as a net producer of fish protein and oil
Posted on October 14, 2011 by admin
Linked to our previous post ‘The future of Fishmeal and Fish oil in Aquaculture’, the following article demonstrates that salmon farming can be a net producer of fish protein and oil.
Demonstration of salmon farming as a net producer of fish protein and oil.
V.O.Crampton, D.A.Nanton, K. Ruohonen, P-O. Skjervold, and A. El-Mowafi
EWOS Innovation AS, Dirdal, Norway
Aquaculture Nutrition 2010 16; 437-446
doi: 10.1111/j.1365-2095.2010.00780.x
Previous studies has used whole fish weight-based calculations to estimate that salmon farming uses between 3.2 and 8.5 kg of capture fish to produce 1 kg of farmed salmon and thus conclude that salmon farming is a net user of marine seafood rather than a net producer. This highlights concern that large fisheries for fishmeal and fish oil could collapse and raises the issue of the responsible use of this resource by the salmon industry. However, this calculation method is an over simplification of the resource usage because it neglects the nutrient composition of both the capture fish and the salmon, thus ignoring the value of the production to human nutrition. Because the lipid content of salmon is nearly three times higher than in capture fish, calculations of reliance should preferably allow for this difference, which can be easily achieved by using, not simple weight-to-weight ratios, but nutrient-to-nutrient ratios. It proposes a simple ‘Marine nutrient dependency ratio’
(MNDR), for which the amount of each marine-derived nutrient used to feed salmon is divided by the amount of each nutrient produced as a result of salmon farming. As the nutrient ratios for proteins and lipids are of primary interest they are termed here as ‘Marine Protein Dependency Ratio’ (MPDR) and the ‘Marine Oil Dependency Ratio’(MODR), respectively. The benefits of using ratios based on nutrients rather than weight are several reflecting the fact that aquaculture feed manufacturers use proteins and lipids, not whole fish. Reductions in the amounts of marine nutrients used will be reflected in a more favourable ratio meaning it will encourage good environmental practice.
In the current study a low marine ingredient feed containing approximately 165 g kg-1 fishmeal was compared to a control feed (approx 300 g kg-1 fishmeal) whilst fish oil inclusion was less markedly reduced. The trials reported here aim to demonstrate a reduction in the dependency on marine protein and oil to <1and compare the growth and fillet composition of fish fed the control feed with those fed a low marine ingredient feed in practical environment. The low marine feeds were found to support similar growth and feed efficiency when compared to the control feeds. With the low marine ingredient feeds, the weight of salmon protein and lipid produced through growth exceeded the weight of marine protein and lipid consumed by the fish meaning that salmon farming can be a net producer of fish protein and oil. The amount of n-3 long-chain polyunsaturated fatty acids deposited was sufficient to meet current recommendations from human health organizations.
The future of fishmeal and fish oil in aquaculture diets
Dr Andrew Jackson, Technical Director, International Fishmeal and Fish Oil Organisation (IFFO), the global trade association representing fishmeal and fish oil producers and related trades, visited the Institute of Aquaculture and gave a talk on ‘The Future of Fishmeal and Fish Oil in Aquaculture Diets’. His visit was supported through the SEAT project, which is currently looking at whole life cycle factors that play in the trade of fish and fishery products between Europe and Asia.
During the presentation and the discussion that followed, several important points of relevance to SEAT and the global trade in farmed aquatic products emerged.
- Fishmeal is an excellent high protein feed ingredient used at least at some stage in almost all intensive aquaculture systems. Indeed the last 40 years has witnessed a definitive shift in usage of fish meal from the agricultural sector to the aquaculture sector – in 1960, chicken and pigs used over 98% of fish meal production, however, in 2008, this had dropped to 40% of usage with the remaining 60% utilised by the aquaculture sector.
- With the recent introduction of precautionary quotas and an increased use of small species of fish for direct human consumption, fewer whole fish and more by-products i.e. inedible products left after fish processing, are now being used as raw materials for fish meal. It is estimated that, with the growth of aquaculture, more and more of the by-products will come from farmed species – with a projected 50% by 2020.
- Global aquaculture production has continued to grow, however, usage of fish meal and fish oil has remained relatively static. Fish meal and fish oil are now used as strategic ingredients rather than as a commodity in fish feeds – in 2009 63% of global fishmeal production went to the aquaculture section, however an estimated three quarters of this was utilised by the intensively farmed species such as salmon and trout, marine species and crustaceans that require a high inclusion level of fishmeal in their diets. Similarly in 2009 an estimated 81% of global fish oil went to the aquaculture feed industry, however 68% of that was utilised for salmonid feeds, 19% to marine species and the remaining 13% to species such as tilapia and crustaceans e.g. shrimp and prawns.
- Importantly, fish meal consumption in Asia– which forms half of worldwide consumption with China forming by far the largest single market – has not increased over the last few years, in spite of the fact that aquaculture production has grown significantly in th Region. Species that can be produced extensively such as shrimp and prawn rely less heavily on high inclusion fish meal feeds and pangasius, an omnivorous species, requires low amounts of fish meal inclusion in their diets.
- Following concerns over the safety of the final fish meal and oil products, the IFFO have developed a Global Standard for Responsible Supply (IFFO RS). A processing factory must comply with a number of good manufacturing practice standards regarding its sourcing of raw fish materials in order to ensure product safety, purity and traceability. The first factory was awarded certification in February 2010 and now IFFO-RS holders represents over 25 % of world product ion of fish meal and fish oil. Countries include Peru with 10 accredited companies with 53 factories with a further 7 factories pending, USA, Iceland, Denmark UK/Ireland and Norway.
- Many emerging aquaculture certification schemes place reduction of fishmeal and fish oil at the heart of their sustainability objectives but the general trends suggest that the market forces maybe working effectively and quickly in the same direction. However similar levels of scrutiny regarding the environmental credentials of effective substitutes are often not considered.
- Major centres of production and export of farmed aquatic species that require little fishmeal and oil such as pangasius and tilapia are, or will soon become, major sources of fishmeal and oil production.
