aquaculture: food and energy from the sea

Kenny Black

British Ecological Society Birmingham December 2012

Contents • Aquaculture vs. fisheries • Marine dependence: Fisheries as a feed source • Substitution and finishing diets • Transferring omega 3 genes • Terrestrial dependence: 2050? • New marine sources • Marine biofuels?

http://www.seafoodsource.com/uploadedImages/SeafoodSourcecom/Industry_News/Aquaculture/ScottishSalmon.jpg?width=235&bgcolor=white&scale=both

Aquaculture vs. fisheries • Scotland is already the largest aquaculture producer in the EU, with value at first

point in excess of £400m in 2010 (158kt salmon) • The value of Scottish fish landings in 2011 was £336m (94kt demersal, 193kt

pelagic) • Globally, aquaculture will overtake fisheries as a source of food in about 2018

(FAO)

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A few words about salmon Carbon footprint Product kg CO2 eq/kg edible part Beef 30 Pork 5.9 Chicken 2.7 Farmed Atlantic salmon 2.9 Herring 0.52

Product efficiency Salmon Pig Chicken Lamb Edible yield % 68.3 52.1 46.1 38.2 FCR 1.15 2.63 1.79 6.3 Energy retention % 23 14 10 5 Protein retention % 31 18 21 5

Large regional differences for salmon: 1.78 in Norway, 3.27 in UK

Torrissen, O., Olsen, R.E., Toresen, R., Hemre, G.I., Tacon, A.G.J., Asche, F., Hardy, R.W. and Lall, S. 2011. Atlantic Salmon (Salmo salar): The "Super-Chicken" of the Sea? Reviews in Fisheries Science. 19. 257-278.

Fisheries products in aquafeeds • Salmon are fed high energy diet with high levels of both oil and protein • Once mostly from forage fishery sources, this can now be reduced to 8-12% for oil

and 12-16% for protein by substitution with terrestrial oils and meals without affecting fish health and performance (AQUAMAXIP)

• But the greater the reduction in fish oil, the greater the reduction in omega-3 fatty acids in the products, a key marketing point

• This can be managed to some extent with the use of high fish oil finishing diets

2005 levels Aquamax Fish Meal Fish Oil Fish Meal Fish Oil % % % % Atlantic Salmon 35-45 25-33 12-16 8-12 Rainbow Trout 30-35 20-25 5 5 Sea Bream 40-45 15-20 15 10 Carp 20-25 05-08 0 0

• Globally, aquafeeds utilise about 63% of fishmeal production about 81% of fishoil production

• Prior to intensive aquaculture this resources found other markets – the total production has remain approximately static during this period but with evidence of a recent decline

• Increased aquaculture demand has led to increased price which has led to the development of alternative terrestrial sources – not increased demand for fishmeal/oil

iffo.net

Genetically modified Yarrowia lipolytica

Hatlen, B., Berge, G.M., Odom, J.M., Mundheim, H. and Ruyter, B. 2012. Growth performance, feed utilisation and fatty acid deposition in Atlantic salmon, Salmo salar L., fed graded levels of high-lipid/high-EPA Yarrowia lipolytica biomass. Aquaculture. 364. 39-47

http://wiki.biomine.skelleftea.se/wiki/images/thumb/8/8c/Sphalerite_and_Yarrowia_lipolytica.jpg/500px-Sphalerite_and_Yarrowia_lipolytica.jpg

GE of terrestrial plants • The last decade has seen many genes encoding the primary VLC-PUFA biosynthetic

activities identified and characterized • This has allowed the reconstitution of the VLC-PUFA biosynthetic pathway in

oilseed crops, producing transgenic plants engineered to accumulate omega-3 VLC-PUFAs at levels approaching those found in native marine organisms

• The application of new technologies, for example lipidomics and next-generation sequencing, is providing a better understanding of seed oil biosynthesis and opportunities for increasing the production of unusual fatty acids

• Will fish fed such oils be acceptable to the public - esp. in Europe?

Ruiz-Lopez, N., Sayanova, O., Napier, J.A. and Haslam, R.P. 2012. Metabolic engineering of the omega-3 long chain polyunsaturated fatty acid biosynthetic pathway into transgenic plants. Journal of Experimental Botany. 63. 2397-2410

http://www.newwest.net/images/thumbnails_feature/camelina_close2.jpg http://www.siberiantigernaturals.com/Pix/cam

elina-field-with-tree.jpg

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Are terrestrial sources sustainable? • Plant production uses fossil fuels, fertilisers, pesticides, herbicides,

hybrid/non-native/GM varieties • Agriculture transforms habitats reducing biodiversity • As human population increases to 9-10 billion over the next 40 years and

+4C by 2100, new agricultural space and freshwater resources will become very scarce

• Feeding the 1500kt p.a. of farmed salmon would take the equivalent of about half the agricultural area of Denmark (1.1 million ha)

• So increasing terrestrial contribution to aquafeeds is not an environmental panacea

Duarte, C.M., Holmer, M., Olsen, Y., Soto, D., Marba, N., Guiu, J., Black, K. and Karakassis, I. 2009. Will the Oceans Help Feed Humanity? Bioscience. 59. 967-976.

New Marine sources • Mesopelagic fish (200-1000m)

– Global biomass about 1000 Mt – Largely unexploited – Many are lipid-rich

http://www.dfo-mpo.gc.ca/international/media/images/science_d.jpg

http://www.mar-eco.no/albums/mesopelagic_fishes/Protomyctophum_arcticus_026.sized.jpg

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• Krill – There is presently an Antarctic krill Euphausia superba fishery of about 150kt

from biomass estimates between 50 – 500Mt – Krill must be immediately processed once on board – High concentrations of fluoride (6g/kg dw) which, through interference with

calcium metabolism, is considered toxic to humans above 150 mg/kg - but F is not significantly retained by salmon

Wilding, T. A., Kelly, M. S. and Black, K. D. (2007) Alternative marine sources of protein and oil for aquaculture feeds: state of the art and recommendations for further research. The Crown Estate, 63 pages, December 2006. ISBN 978-0-9553427-4-5.

http://www.proteinpower.com/drmike/archives/Krill_Water.jpg

• Copepods – Widely used in hatcheries (artemia) – If 10% trophic level efficieny then 100kt of forage fish = 1Mt of copepods? – But catching copepods likely to be too energy intensive!

Bogevik, A.S., Henderson, R.J., Mundheim, H., Olsen, R.E., Tocher, D.R. (2011) The effect of temperature and dietary fat level on tissue lipid composition in Atlantic salmon (Salmo salar) fed wax ester-rich oil from Calanus finmarchicus. Aquaculture Nutrition, 17: e781-e788.

http://www.sintef.no/project/calanus/graphics/calanus.jpg

http://calanus.no/Userfiles/Sites/images/05.jpg

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...one of the simplest steps to help ensure that the world has enough to eat in 2050 would be to scrap every biofuel target. If all the American maize that goes into ethanol were instead used as food, global edible maize supplies would increase by 14%. Governments are unlikely to abandon biofuels merely because they are inefficient and damaging. “We can’t produce biofuels and feed the world’s increased population”.

ENERGY or FOOD

www.economist.com/specialreports/

Energy crop at sea: not in competition for land space and fresh water.

Aquatic plants are more efficient than land plants at converting sunlight to sugars

We have large resources – our coastline and the expertise in our aquaculture industry.

Macroalgae (seaweed) can be used to generate methane (biogas) via anaerobic digestion

We can also produce ethanol and a wide variety of biomedical and nutraceutical compounds and of course, food!

Symon with 1 plant of cultured Sacchoriza polyschides

Kelly and Dworjanyn. 2008. The potential of marine biomass for anaerobic biogas production. The Crown Estate, 103 pages, ISBN: 978-1-906410-05-6

Indicative area needed to grow enough seaweed to meet domestic gas requirements of 10% of Scottish homes based on a production of 20 dry tonnes per hectare (860 km2,

shown here as distributed boxes or one large box, drawn to scale )

Hughes AD, Kelly MS, Black KD and Stanley MS (2012) Biogas from Macroalgae: is it time to revisit the idea? Biotechnology for Biofuels, 5:86 doi:10.1186/1754-6834-5-86

Summary • Salmon are very efficient at converting feed to meat and are excellent as a

vehicle for essential fatty acids • Fish oil and meal are finite resources and are increasingly substituted with

vegetable alternatives in aquafeeds • Genetic modifications yield the prospect of “fish oils” from plants and yeasts • Issues relating to sustainability of terrestrial sources…. • There are presently unexploited marine sources • Aquaculture has potential to contribute to decarbonisation using macroalgae

kenny.black@sams.ac.uk