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Introduction to the problem and scale

  • In 2018, 82 million tonnes of fish were caught from the wild1, three quarters of which are for human consumption – around 20% were ground down to fishmeal and oil2.
  • It is estimated that annual fish catches represent between 790 billion and 2.3 trillion individual fish3 This compares with around 77 billion terrestrial animals slaughtered for food each year4, 5.
  • Wild-caught fish are typically likely to die from asphyxiation in air, on ice or in iced-water6 and they may be bled by the gills without pre-stunning. These are all methods which, according to OIE, “have been shown to result in poor fish welfare.” For farmed fish, OIE goes on to recommend that these methods should not be used where other methods, including electrical and mechanical stunning and spiking, are feasible7.
  • Many wild fish are processed - for example, gutted - whilst still alive. One Dutch study which examined fishing for herring, cod, whiting, sole, dab and plaice, showed that the fish took 55 - 250 minutes to die from asphyxiation. Those who were gutted first remained conscious for 25 - 65 minutes8.
fish asphyxiating in bloody water
  • Traditional methods of humane slaughter of wild fish include mechanical stunning (e.g. a blow to the head) or spiking (where the brain is destroyed with a sharp instrument)9. The latter is used in the production of sashimi since the reduced stress to the fish results in better flesh quality.
  • Modern methods of humane fish slaughter include automatic percussive stunning and electrical stunning since semi-dry or in water. Some modern trawlers use electrical stunning for health and safety reasons (fish that are not struggling are safer to process), or to ensure higher quality, or more accurate filleting10. Their systems could easily be adapted to ensure a humane stun11.
  • Cephalopods such as octopus and squid and decapods such as lobster, crabs, and prawns, are also caught in enormous numbers not yet estimated. According to EFSA, there is good evidence for sentiency in these creatures12. Cephalopods may be left to die en masse in a net or other container, sometimes chilled; or killed with blunt trauma, mantle inversion, or through damage to the brain13.
  • Nearly 94% of fish stocks are overfished or fully exploited. According to FAO, 34.2% of fish stocks were exploited at biologically unsustainable levels in 2017, up from 10% in 197414. A further 59.6% were fully exploited.

How are wild fish affected by factory farming?

  • Wild fish live free, but the methods of capture and processing are often industrial, with no concessions made towards their welfare needs; the potential for suffering is therefore huge.
  • Feeding wild fish to farmed animals and carnivorous farmed fish is a major driver of the sheer numbers of wild-caught fish disappearing from our oceans.
  • Approaching 18 million tonnes of world fisheries production in 2018, 18% of the total, was landed specifically for reduction to fishmeal and oil, the great majority of it used for farm animal feed14. The actual number may be higher since many fisheries are indiscriminate in their catches15
  • It is estimated that between 460 billion and 1.2 trillion fish are caught each year to be reduced into fishmeal and oil16 which likely represents more than half the wild fish reported to be captured each year.
  • According to industry figures, 75% of fish oil is used in aquaculture feeds17 70% of fishmeal is used in aquaculture, while over 22% is used in pig feed and 6% in chicken feed18.
  • When fishmeal is fed to farm animals, 60-86% of the protein content is likely to be lost to the human food chain. According to one study, only 28% of the protein fed to farmed salmon ends up in human-edible food. The study also calculated figures for chickens (37%), pigs (21%), trout (22%), whiteleg shrimp (22%), pangasius (17%) and giant tiger prawn (14%), all of whom may consume fishmeal in their diet, especially the fish and crustaceans.19
  • A 10g Peruvian anchovy containing 19.1% protein20 provides half a gram of farmed salmon protein, around 1% of the daily protein requirement21.
  • 90% of fishmeal and oil comes from food-grade species22 which can be, and are, eaten by people. Farm animals, including farmed fish, are competing with people for food and wasting valuable resources.
  • Fishmeal production is mainly sourced from forage fish species that play a vital role in ecosystems, competing for food with large fish, marine mammals and seabirds, putting their populations at risk23.
  • The expansion of anchovy fishing in the second half of the last century is associated with a reduction in seabird populations from 20 million to 5 million23 Researchers found a strong correlation between these reductions and the number of anchovies available due to fishing and other environmental factors. “Today, many of the bird islands of Peru are largely devoid of seabirds”23.
pile of dead anchovies
  • Increasing demand for fishmeal and oil from intensive farming may encourage the development of as yet unexploited mesopelagic fishing. These fish swim deep in the middle of the ocean and are small. The use of fine nets (with a mesh size of less than 1cm, catching fish unselectively), requiring considerable energy24 (with implications for carbon emissions) will have a damaging impact on biodiversity.
  • The forage fish in the mesopelagic zone play an integral role in carbon sequestration and thus climate regulation25, 26, and are a key food resource for marine mammals and fisheries stocks such as tuna, billfish, and sharks27, 28 thereby influencing and maintaining biodiversity.
  • The potential biomass of this fishery has been estimated between 2 and 19.5 billion tonnes29. Key target species include: the lanternfish Gymnoscopelus braueri (weighs up to 20g); Krefftichthys anderssoni, (weighs up to 4-5g)30; and the pearlside, Maurolicus muelleri, (weighs around a gram and up to 2g at maturity)31, 32. Up to a quadrillion fish* are therefore at risk.
    *A quadrillion is 1,000,000,000,000,000 – a million billion or a thousand trillion.
  • The use of wild-caught fish as a source of food for farm animals is harmful to the biodiversity of our oceans and removes food which people could be eating.
  • The inclusion of fishmeal and oil in the diet results in the transfer of toxic substances such as PCBs, dioxins, and pesticides into farmed fish. PCBs and, to a lesser extent organochlorine pesticides, have been detected in farmed salmon and in the fishmeal and oil, they are fed on33. Reducing fish oils in the diet reduces the levels of PCBs and dioxins in the salmon34. Though levels are below legal limits for moderate consumption, this issue could be reduced by replacing fishmeal with other proteins and fish oil with algal oils.
  • ARGs (antibiotic resistance genes) and human potential pathogenic bacteria have been found in 5 fishmeal samples widely used in aquaculture in China and imported from Peru, Russia, Chile or China35.
  • Fish feed contaminated with microplastics may be a risk to aquaculture. Fishmeal is commonly produced from whole fish and large numbers of small pelagic fishes, at risk of direct uptake of microplastics mistaken for food items, which may pass into the processed fishmeal36
  • Reducing over-fishing can have the following benefits
    • Allows fish stocks to recover, allowing marine life to thrive as well as the communities that depend on them.
    • Lowers fishing carbon emissions by reducing the energy expended.
    • Allows fish to grow larger before they are caught which means less animal suffering per tonne of fish caught.
  • Avoiding catches off Africa leaves more fish for small-scale fishers and direct human consumption.
  • Supporting the development of humane capture and slaughter techniques is likely to improve the quality of the product by reducing stress and injury. This would also prevent suffering for thousands of fish during the slaughter process and may benefit, in the future, hundreds of billions of fish per year.
  • Supporting sales of plant-based foods, including fish alternatives, would:
    • Reduce demand and therefore reduce pressure on fisheries.
    • Reduce reliance on an industry that supports deforestation and other habitat destruction (by reduced demand for farmed fish feeds containing soya).
  • Reducing the use of fishmeal and oil, excluding that from trimmings, in farm feeds, especially in aquaculture, reduces pressure on fisheries and leaves more for direct human consumption. Policies to avoid the use of any fishmeal and oil from mesopelagic fisheries may help to prevent the development of an industry that could have a negative impact on oceanic food chains and the welfare of massive numbers of fish.
  • Supporting the development of alternatives to fishmeal and oil such as algae oils and microbial proteins, in addition to increased use of trimmings to make fishmeal and oil, could ultimately:
  • Improve human nutrition, especially for the more widespread availability of long-chain omega-3 fatty acids (as direct human food as well as via animal foods).
  • Reduce reliance on an industry that supports deforestation and other habitat destruction and release land for rewilding and sea space for marine reserves.
  • Enable seabird populations to recover and provide additional food supplies for predatory fish and sea mammals.
  • Protect hundreds of billions of forage fish from suffering during capture.

Link to the relevant Sustainable Development Goal (SDG)

  • SDG 14: Life below water. Conserve and sustainably use the oceans, seas, and marine resources for sustainable development37.
  1. FAO Fishstat, accessed 2020
  2. Calculated from Fishstat, accessed 2020, and FAO, 2020, The State of World Fisheries and Aquaculture
  3. Mood, A., 2019. Fishcount estimates: Numbers of fish caught from the wild each year.
  4. Calculated from FAOSTAT figures for 2017 – it was less over the 2007-16 period and 51-167 billion farmed fish
  5. Mood, A., Brooke, P., 2019. Fishcount: Estimated numbers of individuals in global aquaculture production (FAO) of fish species (2017).
  6. Mood, A., 2010. Worse things happen at sea. Fishcount.
  7. 1 OIE, 2012. Welfare aspects of stunning and killing of farmed fish for human consumption.
  8. Van de Vis and Kestin, 1996. Killing of fishes: literature study and practice observations (field research) report
  9. Gregory, N.G. and Grandin, T., 1998. Animal welfare and meat science (No. 636.08947 G7). CABI Pub.
  10. SINTEF, 2016. Better fish welfare means better quality. SINTEF news.
  11. Mood, A., Brooke, P. (2019). Towards a strategy for humane fishing in the UK.
  12. Panel, A.H.A.W., 2005. Aspects of the biology and welfare of animals used for experimental and other scientific purposes. The EFSA Journal, 292, pp.1-46.
  13. Pereira, J and Lourenco, S., 2014. What We Do To Kill an Octopus. Cephsinaction.
  14. FAO. 2020. The State of World Fisheries and Aquaculture 2020. Sustainability in action. Rome.
  15. Cashion, T., Le Manach, F., Zeller, D. and Pauly, D., 2017. Most fish destined for fishmeal production are food‐grade fish. Fish and Fisheries, 18(5), pp.837-844.
  16. Mood, A., Brooke, P, 2019. Estimate of numbers of fishes used for reduction to fishmeal and fish oil, and other non-food purposes, each year. Fishcount. Details by species.
  17. Auchterlonie, 2018, cited in FAO, 2018, op cit.
  18. IFFO, 2016. IFFO Fishmeal and Fish Oil Statistical Yearbook 2016 cited in Seafish, 2016, Fishmeal and fishoil facts and figures.
  19. Fry, J.P., Mailloux, N.A., Love, D.C., Milli, M.C. and Cao, L., 2018. Feed conversion efficiency in aquaculture: do we measure it correctly?. Environmental Research Letters, 13(2), p.024017.
  20. Peru-info website, Super anchovy.
  21. WHO, 1985. Energy and protein requirements. Part 8. Summary of requirements for energy and protein.
  22. Cashion, T., Le Manach, F., Zeller, D. and Pauly, D., 2017. Most fish destined for fishmeal production are food‐grade fish. Fish and Fisheries, 18(5), pp.837-844.
  23. Jahncke, J., Checkley Jr, D.M. and Hunt Jr, G.L., 2004. Trends in carbon flux to seabirds in the Peruvian upwelling system: effects of wind and fisheries on population regulation. Fisheries oceanography, 13(3), pp.208-223.
  24. Prellezo, R., 2019. Exploring the economic viability of a mesopelagic fishery in the Bay of Biscay. ICES Journal of Marine Science, 76(3), pp.771-779.
  25. Hidaka, K., Kawaguchi, K., Murakami, M. and Takahashi, M., 2001. Downward transport of organic carbon by diel migratory micronekton in the western equatorial Pacific:: its quantitative and qualitative importance. Deep Sea Research Part I: Oceanographic Research Papers, 48(8), pp.1923-1939.
  26. Hudson, J.M., Steinberg, D.K., Sutton, T.T., Graves, J.E. and Latour, R.J., 2014. Myctophid feeding ecology and carbon transport along the northern Mid-Atlantic Ridge. Deep Sea Research Part I: Oceanographic Research Papers, 93, pp.104-116.
  27. Potier, M., Marsac, F., Cherel, Y., Lucas, V., Sabatié, R., Maury, O. and Ménard, F., 2007. Forage fauna in the diet of three large pelagic fishes (lancetfish, swordfish and yellowfin tuna) in the western equatorial Indian Ocean. Fisheries Research, 83(1), pp.60-72.
  28. Brophy, J.T., Murphy, S. and Rogan, E., 2009. The diet and feeding ecology of the shortbeaked common dolphin (Delphinus delphis) in the northeast Atlantic. IWC Scientific Committee Document SC/61/SM, 14.
  29. Sobradillo, B., Boyra, G., Martinez, U., Carrera, P., Peña, M. and Irigoien, X., 2019. target Strength and swimbladder morphology of Mueller’s pearlside (Maurolicus muelleri). Scientific reports, 9(1), pp.1-14.
  30. Saunders, R.A., Lourenço, S., Vieira, R.P., Collins, M.A., Assis, C.A. and Xavier, J.C., 2020. Age and growth of Brauer's lanternfish Gymnoscopelus braueri and rhombic lanternfish Krefftichthys anderssoni (Family Myctophidae) in the Scotia Sea, Southern Ocean. Journal of Fish Biology, 96(2), pp.364-377.
  31. Rasmussen, O.I. and Giske, J., 1994. Life-history parameters and vertical distribution of Maurolicus muelleri in Masfjorden in summer. Marine Biology, 120(4), pp.649-664.
  32. ROSLAND, R. and GISKE, J., 1997. A dynamic model for the life history of Maurolicus muelleri, a pelagic planktivorous fish. Fisheries Oceanography, 6(1), pp.19-34.
  33. Jacobs, M.N., Covaci, A. and Schepens, P., 2002. Investigation of selected persistent organic pollutants in farmed Atlantic salmon (Salmo salar), salmon aquaculture feed, and fish oil components of the feed. Environmental science & technology, 36(13), pp.2797-2805.
  34. Bell, J.G., McGhee, F., Dick, J.R. and Tocher, D.R., 2005. Dioxin and dioxin-like polychlorinated biphenyls (PCBs) in Scottish farmed salmon (Salmo salar): effects of replacement of dietary marine fish oil with vegetable oils. Aquaculture, 243(1-4), pp.305-314.
  35. Han, Y., Wang, J., Zhao, Z., Chen, J., Lu, H. and Liu, G., 2017. Fishmeal application induces antibiotic resistance gene propagation in mariculture sediment. Environmental science & technology, 51(18), pp.10850-10860.
  36. Lusher, A., Hollman, P. and Mendoza-Hill, J., 2017. Microplastics in fisheries and aquaculture: status of knowledge on their occurrence and implications for aquatic organisms and food safety. FAO.
  37. United Nations Department of Economic Social Affairs Sustainable Development
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