In a recent post I commented on the sustainability aspects of our sport that had led me to adopt catch and release in all aspects of my fishing. This includes my Midlands reservoir fishing, catching predominantly stockies (hopefully once they’ve grown on), and was in part motivated by the inputs of wild caught fish used to farm these stockies in the first place. Farmed fish are fed on aquafeeds that contain fish meal and fish oil harvested from marine sources, think anchovies, sandeels and herring. In 2009, this harvest comprised 18 million tonnes of whole fish and 5 million tonnes of trimmings to produce 4.83 million tonnes of fish meal and 1.01 million tonnes of fish oil with aquaculture taking about 73% and 71% of these harvests, respectively.
While the levels of these marine harvested ingredients can vary greatly between aquafeed brands, trout aquafeeds were typically comprised of around ~17% to ~22% fish meal and ~7% to ~13% fish oil in 2010. This is lower than it has been in the past, being ~40% fish meal and ~20% fish oil in 1995, and is expected to fall further to about half of the 2010 levels by 2020. This change is described by the FIFO or Fish In Fish Out ratio which simplistically is the ratio of the kilograms of wild caught fish used to produce 1 kilogram of farmed fish. For example, a FIFO ratio of 4 indicates that 4 kilograms of wild caught fish were used to produce 1 kilogram of farmed fish. The aquaculture industry producing salmon and trout have been working towards a FIFO of at least 1, that is for every kilogram of fish input into the production process one kilogram of fish is produced by fish farms. While some well run fish farms have achieved this ambition, this is not the norm. In the interim the industry has also focussed on ensuring that fish meal and oil used in aquafeeds are from certified sustainable sources, with 90% of aquafeeds used in the EU now being certified.
However, calculating the FIFO ratio is not straight forward as it requires an assessment of the global marine harvest for fish meal and oil production and a range of assumptions e.g. how much fish meal and oil is yielded from this catch. It also requires estimates of the inclusion levels of fish meal and oil in the aquafeeds of different farmed fish and crustacean species as well as estimates of how effectively these farmed species convert the feed into live weight gain as they grow (feed conversion ratio) during different life stages. Initial estimates produced a FIFO for trout of 2.0 for 2010; which is lower than historical levels, being 4.2 in 2000 and expected to continue falling to 1.5 in 2015 and 1.0 by 2020. However, revisions to the calculation method to remove a fish oil based bias of fish meal levels used in aquafeeds as well as to account for the increasing use of fish byproducts (heads, guts, bones and other waste) from the production of fillets in fish meal and oil changes this picture with revised FIFOs of 2.6 in 2000, 1.4 in 2010 and 0.8 in 2015. Given all of the uncertainties in the data that underpin these numbers and the assumptions/generalisations made in processing them, these numbers should be treated as an indicator of change rather than absolute numbers. However, one thing is clear and that is that the FIFO is falling and will continue to fall owing to: (1) increasing volumes of byproducts being used to produce fish meal and oil; (2) improved feed conversion ratios through use of improved technology and fish farm practices; (3) falling levels of fish meal and oil in aquafeeds being replaced with terrestrial proteins and oils and (4) better formulation of aquafeeds making better strategic use of that fish meal and oil which is used.
While consideration of aquaculture production using other metrics like nutrient value or carbon footprint paint the industry in a better light versus other terrestrial based production systems like beef this is not what this article is about i.e. it is not designed to be a critical appraisal of this industry. Similarly, it isn’t trying to have a go at those fishermen who occasionally or even frequently take fish included in the cost of their day ticket for the pot. It is simply a prompt to those who mistreat fish during the catch & release process, kill a fish simply for the trophy photoshot or so they can spoon it and take fish they do not need only to throw them away later with freezer burn or feed them to the cat: it is not just this fish you are killing needlessly but also all the other harvested marine fish to produce it in the first place. Your double figure (in pounds) trophy trout is at least 4.5 kg while a 15 cm long adult anchovy weighs about 60 grams, hence using a FIFO index of 1.4 an estimated 105 wild anchovy were harvested to produce this trophy fish. This says nothing about the kilograms of terrestrial plant based protein and oils in this feed and the environmental impact of its production. So next time you go fishing perhaps be better prepared to take your trophy photoshot while releasing the fish or only take fish you know will not survive if released or you will eat in the next 4 months while it is at its best.
Tight lines
Greg
References
1 Tacon, A.G.J. & Metian, M. (2008). Global overview on the use of fish meal and fish oil in industrially compounded aqua-feeds: trends and future prospects. Aquaculture, 285, 146-158.
2 Kaushik, 2012. Aquaculture in the reform of the common fisheries policy. European parliament, Brussels.
3 https://www.iffo.net/position-paper/fish-fish-out-fifo-ratios-conversion-wild-feed
4 https://www.feap.info/default.asp?SHORTCUT=603
5 Jackson, 2012. Feeding fish to fish and the sustainability of aquaculture. Aquaculture in motion, Brussels.
6 Albert G J Tacon; Mohammad R Hasan; Marc Metian, 2011. Demand and supply of feed ingredients for farmed fish and crustaceans : trends and prospects. Food and Agriculture Organization of the United Nations.
7 Andrew Jackson: Fish In- Fish Out, Ratios Explained. Aquaculture Europe, Volume 34(3) 2009.
8 https://www.fishforthought.co.uk/frozen_facts.htm
9 https://www.wrs.co.uk/our-story/
