Chapter 14. Seaweeds
Contributors: John West and Hilconida P. Calumpong (Co-lead member), Georg Marti (Lead member)
1. Introduction
Seaweeds are a group of photosynthetic non-flowering plant-like organisms (calle macroalgae) that live in the sea. They belong to three major groups based on thei dominant pigmentation: red (Rhodophyta), brown (Phaeophyta) and gree (Chlorophyta). Seaweeds were traditionally and are currently still used as food in China Japan and the Republic of Korea. About 33 genera of seaweeds, mostly red and brown are harvested and farmed commercially (McHugh, 2003), although close to 500 specie in about 100 genera are collected and utilized locally (Mouritsen, 2013). Currentl about 80 per cent of total seaweed production is for direct human consumption, eate dried or fresh for its nutritional value or for flavouring (see Kilinc et al., 2013 for  comprehensive listing of nutrients and compounds) in the form of sushi, salad, soup dessert and condiments, and the remaining 20 per cent is used as a source of th phycocolloids extracted for use in the food, industrial, cosmetic, and medical industr (Browdy et al., 2012, Critchly et al., 2006, Lahaye, 2001, McHugh, 2003, Mouritsen 2013, Ohno and Critchley, 1993), as well as for animal feed additive, fertilizer, wate purifier, and probiotics in aquaculture (Abreu et al., 2011, Chopin, 2012, Chopin et al. 2001, Chopin et al., 2012, Fleurence et al., 2012, Kim et al., (2014), Neori et al., 2004 Pereira and Yarish, 2008, 2010, Rose et al., 2010). Carrageenan and agar are extracte from red seaweeds, and alginates and fucoidan are extracted from brown seaweeds generally from kelp species. Recently, the kelp species Saccharina lattisima wa considered for bioethanol production (Adams et al., 2009).
2. Production
World production of seaweeds comes from two sources: harvesting from wild stock and from aquaculture (including land-based culture, mariculture and farming) Production from harvesting of wild stocks has been stable at over 1 million tons (we weight) in the last 10 years (2003 to 2012) according to FAO (2014) statistics (see Figur 1). Top producers in 2012 were Chile (436,035 tons representing 39 per cent of tota world production), China (257,640 tons or 23 per cent), Norway (140,336 or 13 pe cent), Japan (98,514 or 9 per cent), France (41,229 tons or 4 per cent), Ireland (29,50 tons or 2.73 per cent), Iceland (18,079 tons or 2 per cent), South Africa (14,509 tons or  per cent) and Canada (13,833 tons or 1 per cent). Contributing less than 1 per cent eac were 24 other countries. Chile has consistently been the number one top produce © 2016 United Nations  

since 2003, except in 2007 when China exceeded Chile’s production by 1 per cent Norway and Japan have maintained their position as third and fourth top producers respectively, since 2003.
Three countries posted only one year’s production in 10 years (Namibia in 2003 wit 408 tons, Samoa in 2004 with 478 tons, Senegal in 2012 with 1,028 tons. India posted  ton of production in 2004 to 2008, except in 2005 when it posted 2 tons of production).
World Seaweed Harvest from Wild Stocks by Country/Territory (Dat from FAO 2014)
140 1200 Hi  _ z 100 80  Z   > 60  x   » 40 x 8   & 20  w   C e  2003 2004 2005 2006 2007 2008 2009 2010 2011 201 m Australia m Canada m Chile m@ China, incl. Taiwa @ Others m Estonia m Fiji m Franc mlceland m Indonesia mlreland mltal mJapan m Korea Rep m Madagascar m Mexic m= Morocco m New Zealand m Norway m Peru
Figure 1. World seaweed production from wild stocks in 2003-2012 by country/territory in tons we weight. Data from FAO, 2014. Four countries with production in 10 years of less than 1000 tons or wit only one production within 10 years are lumped under Others (see text) tp://www.fao.org/fishery/statistics/software/fishstatj/en.
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The bulk of seaweeds produced worldwide come from aquaculture. The FAO (2014 reported that the production of aquatic seaweeds from mariculture, reached 24. million tons in 2012, valued at about $6 billion United States dollars. The red, brow and green seaweeds constitute about 88 per cent (21 million tons). About 96 per cen (23.8 million tons) of the total production were produced from aquaculture (see Figur 14.2). Data from FAO showed a steady increase of about 8 per cent per year over th last 10 years (range of 4-12 per cent), specifically for red seaweeds (Figure 3) with th brown seaweeds showing stable production. The cultured seaweeds are mainly thos that produce carrageenan (Kappaphycus alvarezii and Eucheuma spp. - 8.3 million tons) followed by the alginate-producing brown seaweeds (kelps - 5.7 million tons). China i the consistent top supplier, although showing a decreasing trend, with 50 per cent o the world production over a 10-year period (2003-2012). The Philippines ranked secon in 2003 to 2006, producing 9-10 per cent, after which it was overtaken by Indonesia. Th Democratic People’s Republic of Korea, the Republic of Korea, and Japan produce between 2-5 per cent of the annual total, and 31 other countries produced less than  per cent of the annual total, except for Malaysia, which showed an increasin production equivalent to 1.09-1.39 per cent of the annual global quantity during 2010 t 2012.
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25000
20000
15000
10000
5000
Tonnes wet weight
World Seaweed Production From Aquaculture in 2003-2012 b Country/Territory (Data from FAO, 1914)
2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
China i Indonesia @ Philippines
@ Korea, Republic of @ Korea, Dem. People's Rep Japan
@ Malaysia VietNam @ Zanzibar
Solomon Islands § Kiribati ™ Tanzania, United Rep. o ™ Denmark @ India = Chile
™ Taiwan POC = South Africa @ Russian Federatio Timor-Leste @ Madagascar @ Brazil
MFiji, Republic of & Myanmar ™@ France
| Tonga ™ Peru | Namibia
Figure 2. World seaweed production from aquaculture in 2003-2012 by country/territory in tons we weight. Data from FAO 2014. http://www.fao.org/fishery/statistics/software/fishstatj/en.
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World Seaweed Production and Value from Aquaculture 2003-201 by Species Group (Data from FAO, 2014)
14000 400 @ 1300 & 12000 350 2 11000 300 = 10000  c  = 9000 2500  = 8000  5  ‘37000 2000  = y 2 6000  2 5000 150 % 4000  vu
1000  e 3000  = 2000 500
100 0 0
2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
Mam BROWN SEAWEEDS tonnes mall RED SEAWEEDS tonne mmm GREEN SEAWEEDS tonnes ———= BROWN SEAWEEDS US $
———GREEN SEAWEEDS US$ === RED SEAWEEDS US $
Figure 3. World aquaculture production from 2003-2012 by species groups in tons wet weight and tota value in United States dollars per group. (Unidentified aquatic plants excluded.) Green algae production i minimal, as shown in this graph. Data from FAO 2014.
3. Social and economic impacts and challenges
Harvests from wild populations are affected by overexploitation and climatic changes In Northern Ireland, for example, which is listed as one of the top 10 producers of wil stocks globally (FAO, 2014), McLaughlin et al., (2006) described in detail the advers impacts of seaweed harvesting at small, artisanal and commercial scales on areas o conservation importance, protected and priority habitats and species, includin disturbance of birds and wildlife, disruption of food webs, damage to substrata, habita destruction, localized biodiversity changes, and changes in particle-size distribution i sediments. Direct effects on the seaweed population include mortalities due t increased growth rate and cover of other algae which are not harvested, such a filamentous green algae and the brown seaweed, Fucus vesiculosus, which outcompet the desired species, and die-back due to increased predation. In several areas o Norway, the kelp Saccharina lattisima has been reported by Moy and Christie (2012) t have suffered dieback by 40-80 per cent due to sea urchin predation.
The brown seaweed kelps are most affected by rising water temperature, becaus sexual reproduction (gamete formation) in most kelps will not occur above 20°C (Dayto 1985, Dayton et al., 1999). Already along the European coasts and especially in Brittany © 2016 United Nations  

France, the brown kelp, Laminaria digitata, which is heavily harvested for commercia uses, is reported to be on the verge of local extinction. The already reduce reproductive potential of the kelp due to dwindling population and harvesting-induce ecosystem changes may be exacerbated by climate-caused increase in sea temperatur (Brodie et al., 2014, Raybaud et al., 2013). Two other kelp species, Laminari ochroleuca, a warm-temperate perennial, and Saccorhiza polyschides, a wide-rangin cool- to warm-temperate annual, have somewhat higher temperature tolerances fo sexual reproduction than other kelps (Pereira et al., 2011); however, Saccorhiz outcompetes L. ochroleuca in shared habitats. Brittany is the northern limit of L ochroleuca’s range. Since 1940, L. ochroleuca has been found on the coasts of souther England, which is apparently indicative of a slow northward extension of warme waters. Anticipated increasing ocean temperatures in the future in the boreal regio may result in L. ochroleuca possibly replacing L. hyperborea (Brodie et al., 2014). On th other hand, the kelp Ecklonia maxima is extending eastward on the tip of South Afric because of a northward intrusion by cooler inshore water (Bolton et al., 2012); thi could greatly benefit the whole ecosystem and provide more food for the abalon industry there. All this is quite a contrast from southward intrusion patterns by war water on the east and west coasts of Australia, causing extensive retreat of kelps an fucoids (another group of brown algae) southward from their previous northern-mos limits (Wernberg et al., 2011, Millar, 2007).
Seaweed farming and culture are seriously affected by diseases. Ice-ice disease ha impacted the farming of the kappa-carrageenan-producing Kappaphycus alvarezii commercially called “cottonii”. Another species, Eucheuma denticulatum, commerciall called “spinosum,” is ice-ice-resistant, but contains iota-carrageenan which fetches  much lower price on the world market (Valderrama, 2012). This problem may be a resul of the low genetic variation in K. alvarezii, all of whose cultured stocks around the worl have a similar mitochondrial haplotype, which is not the case for £. denticulatu (Halling et al., 2013; Zuccarello et al., 2006). Significant diseases affecting cultivate kelps (e.g., Saccharina japonica) include green-rot, white-rot, blister disease, which ma be environmentally induced, and malformation disease of summer sporelings an swollen stipe or “frond twist disease" which are caused by bacteria (Brinkhaus et al. 1987, Tseng, 1986). Parasites such as Pythium, an oomycete fungus, causes “red rot” o “red wasting” disease in the red seaweed Pyropia commonly used in making sushi (Hur et al., 2014). However, based on case studies from six countries, Valderrama (2012 reported that the socioeconomic impacts of seaweed farming have been positive. H attributed this mainly to small-scale, family operations resulting in the generation o substantial employment as compared to other forms of aquaculture. He added tha seaweed farming is often undertaken in remote areas where coastal communities fac fewer economic alternatives and where many of these communities have traditionall relied on coastal fisheries which are currently being affected by overexploitation Valderrama stated that the impact of seaweed farming in these cases goes beyond it immediate economic benefits to communities as it also reduces the incentives fo overfishing. However, one challenge faced by farmers in these remote areas is low
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profits due to high shipping costs. This disadvantage is exacerbated by the dependenc of farmers on processors for the procurement of their farming materials and their lac of farm-management skills. In addition, food safety issues can sometimes affec markets and prices. This is because seaweeds are efficient nutrient extractors (Kim e al., 2014) and may accumulate compounds that pose harm to human health (Mouritse 2013; see also Chapter 10).
4. Information and Knowledge Gaps
Despite the long history of utilization, it is reported that kelp-dominated habitats alon much of the NE Atlantic coastline have been chronically understudied over recen decades in comparison with other regions such as Australasia and North America. Fo example, McLaughlin et al. (2006) noted that information on the distribution an biomass of commercial seaweeds in Northern Ireland is lacking. Smale and Wernber (2013) highlight the changing structure of kelp forests in the North- East Atlantic i response to climate- and non-climate-related stressors, which will have majo implications for the structure and functioning of coastal ecosystems. This paucity o field-based research is impeding ability to conserve and manage this importan resource.
References
Abreu, M.H., Pereira, R., Yarish, C., Buschmann, A.H., Sousa-Pinto, I. (2011). IMTA wit Gracilaria vermiculophylla: productivity and nutrient removal performance of th seaweed in a Land-based pilot scale system. Aquaculture 312 (1-4): 77-87.
Adams, J., Gallagher, J., Donnison, |. (2009). Fermentation study on Saccharina lattisim for bioethanol production considering variable pre-treatments. Journal o Applied Phycology 21: 569-574.
Bolton, J., Anderson, R., Smit, A., Rothman, M. (2012). South African kelp movin eastwards: the discovery of Ecklonia maxima (Osbeck) Papenfuss at De Hoo Nature Reserve on the South Coast of South Africa, African Journal of Marin Science 34: 147-151.
Brinkhuis, B.H., Levine, H.G.,Schlenk, C.G., Tobin, S. (1987). Laminaria cultivation in th far-east and North America. In: Seaweed Cultivation for Renewable Resources (Bird, K.T. Benson, P.H., eds.). Developments in Aquaculture and Fisherie Science 16: 107-146.
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Brodie, J., Williamson, C.J., Smale, D.A., Kamenos, N.A., Mieszkowska, N., Santos, R. Cunliffe, M., Steinke, M., Yesson, C., Anderson, K.M., Asnaghi, V., Brownlee, C. Burdett, H.L., Burrows, M.T., Collins, S., Donohue, P.J.C., Harvey, B., Noisette, F. Nunes, J., Ragazzola, F., Raven, J.A., Foggo, A., Schmidt, D.N., Suggett, D. Teichberg, M., Jason M. Hall-Spencer, J.M. (2014). The future of the northeas Atlantic benthic flora in a high CO2 World. Ecology and Evolution 1-12 doi:10.1002/ece3.1105.
Browdy, C.L., Hulata, G., Liu, Z., Allan, G.L., Sommerville, C., Passos de Andrade, T. Pereira, R., Yarish, C., Shpigel, M., Chopin, T., Robinson, S., Avnimelech, Y. Lovatelli, A. (2012). Novel and emerging technologies: can they contribute t improving aquaculture Sustainability? In Subasinghe, R.P., Arthur, J.R., Bartley D.M., De Silva, S.S., Halwart, M., Hishamunda, N., Mohan, C.V., Sorgeloos, P (eds.), Farming the Waters for People and Food. Proceedings of the Globa Conference on Aquaculture 2010, Phuket, Thailand. 22-25 September 2010. pp 149-191. FAO, Rome and NACA, Bangkok.
Chopin, T. (2012). Aquaculture, Integrated Multi-Trophic (IMTA). In: Meyers, R.A. (ed.) Encyclopedia of Sustainability Science and Technology. Springer, Dordrecht, Th Netherlands. pp. 542-64.
Chopin, T., Buschmann, A. H., Halling, C., Troell, M., Kautsky, N., Neori, A., Kraemer, G.P. Zertuche-Gonzales, J.A., Yarish, C., Neefus, C. (2001). Integrating seaweeds int marine aquaculture systems: a key toward sustainability. Journal of Phycolog 37: 975-986.
Chopin, T., Cooper, J. A. ,Reid, G., Cross, S., Moore, C. (2012). Open-water integrate multi-trophic aquaculture: environmental biomitigation and economi diversification of fed aquaculture by extractive aquaculture. Reviews i Aquaculture 4: 209-220.
Critchley, A.T., Ohno, M,. Largo, D.B. (2006). World Seaweed Resources: A Authoritative Reference System. DVD-ROM. Wokingham, UK: ETI Informatio Services.
Dayton, P.K. (1985). Ecology of kelp communities. Annual Review of Ecology an Systematics 16: 215-245.
Dayton, P.K., Tegner, M.J., Edwards, P.B., Riser, K.L. (1999). Temporal and spatial scale of kelp demography: the role of oceanography and climate. Ecologica Monographs 69: 219-250.
FAO. (2014). Fishery and Aquaculture Statistics. Aquaculture production 1950-201 (FishstatJ). In: FAO Fisheries and Aquaculture Department [online or CD-ROM] Rome. Updated 2014 http://www.fao.org/fishery/statistics/software/fishstatj/en.
Fleurence, J., Morangais, M., Dumay, J., Decottignies, P., Turpin, V., Munier, M. Garcia Bueno, N., Jaouen, P. (2012). What are the prospects for using seaweed i © 2016 United Nations  

human nutrition and for marine animals raised through aquaculture? Trends i Food Science & Technology 27:57-61.
Halling, C., Wikstrém, S.A., Lillieskéld-Sj66, G., Mork, E., Lundsgr, E., Zuccarello, G.C (2013). Introduction of Asian strains and low genetic variation in farme seaweeds: indications for new management practices. Journal of Applie Phycology 25:89—95, doi: 10.1007/s10811-012-9842-0.
Hurd, C.L., Harrison, P.J., Bischof, K., Lobban, C.S. (2014). Seaweed Ecology an Physiology, (2nd ed.). Cambridge University Press.
Kiling, B. Cirik, S., Turan, G., Tekogul, H., Koru, E. (2013). Seaweeds for Food an Industrial Applications. http://dx.doi.org/10.5772/53172. In: Food Industr http://cdn.intechopen.com/pdfs/41694/InTech Seaweeds_for_food_and_industrial_applications.pdf
Kim, J.K., Kraemer, G.P., Yarish, C. (2014). Field scale evaluation of seaweed aquacultur as a nutrient bioextraction strategy in Long Island Sound and the Bronx Rive Estuary. Aquaculture 433: 148-156.
Lahaye, M. (2001). Chemistry and physico-chemistry of phycocolloids, Cahiers d Biologie Marine. 42: 137-157.
McHugh, D.J. (2003). A Guide to the Seaweed Industry. FAO Fisheries Technical Pape 441.
McLaughlin, E., Kelly, J., Birkett, D., Maggs, C., Dring, M. (2006). Assessment of th Effects of Commercial Seaweed Harvesting on Intertidal and Subtidal Ecology i Northern Ireland. Environment and Heritage Service Research and Developmen Series. No. 06/26.
Millar, A.J.K. (2007). The Flindersian and Peronian Provinces. In: McCarthy, P. Orchard, A., (eds.), Algae of Australia. An Introduction. CSIRO Publishing Melbourne, pp. 554-559.
Mouritsen, O.G. (2013). Seaweeds Edible, Available & Sustainable. The University o Chicago Press, Chicago & London, 287 pp.
Moy, F., Christie, H. (2012). Large-scale shift from sugar kelp (Saccharina latissima) t ephemeral algae along the south and west coast of Norway. Marine Biolog Research 8: 309-321.
Neori, A., Chopin, T., Troell, M., Buschmann, A.H., Kraemer, G. Halling, C., Shpigel, M. Yarish, C. (2004). Integrated aquaculture: rationale, evolution and state of the ar emphasizing seaweed biofiltration in modern aquaculture. Aquaculture 231: 361 391.
Ohno, M., Critchley, A., (eds.). (1993). Seaweed Cultivation and Marine Ranching. JICA Yokosuka, Japan, i-xvii, 431, i-xii pp.
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Pereira, T., Engelen, A., Pearson, G., Serrdo, E., Destombe, C., Valero, M. (2011) Temperature effects on the microscopic haploid stage development of Laminari ochroleuca and Sacchoriza polyschides, kelps with contrasting life histories Cahiers de Biologie Marine 52: 395-403.
Pereira, R., Yarish, C. (2008). Mass production of Marine Macroalgae. In: Jorgensen, S.E. Fath, B.D., (eds.), Ecological Engineering. Vol. [3] of Encyclopedia of Ecology,  vols. pp. 2236-2247. Elsevier: Oxford.
Pereira, R., Yarish, C. (2010). The role of Porphyra in sustainable culture systems Physiology and Applications. In: Israel, A., Einav, R., (eds.), Role of Seaweeds in Globally Changing Environment. Springer Publishers, pp. 339-354.
Pereira, R., Yarish, C., Critchley, A. (2012). Seaweed Aquaculture for Human Foods i Land Based and IMTA Systems. In: Meyers, R. (eds.), Encyclopedia o Sustainability Science and Technology. Springer Science, N.Y. pp. 9109-9128.
Raybaud,V., Beaugrand, G., Goberville, E., Delebecq, G., Destombe, C. Valero, M. Davoult, D., Morin, P., Gevaert, F. (2013). Decline in Kelp in West Europe an Climate. PLoS ONE 8(6): e66044. doi:10.1371/journal.pone.0066044.
Rose, J.M., Tedesco, M., Wikfors, G.H., Yarish, C. (2010). International Workshop o Bioextractive Technologies for Nutrient Remediation Summary Report. U Department of Commerce, Northeast Fisheries Science Center Referenc Document 10-19; Available from: National Marine Fisheries Service, 166 Wate Street, Woods Hole, MA 02543-1026, or online a http://www.nefsc.noaa.gov/nefsc/publications/12 p.
Smale, D.A., Wernberg, T. (2013). Extreme climatic event drives range contraction of  habitat-forming species. Proceedings of the Royal Society B 280: 20122829.
Tseng, C.K. (1986). Laminaria mariculture in China. In: Doty, M.S., Caddy, J.F. Santelices, B. (eds.), Case studies of seven commercial seaweed resources. FA Fisheries Technical Papers, (281): 311 p.
Valderrama, D. (2012). Social and economic dimensions of seaweed farming: a globa review. IIFET Tanzania Proceedings https://ir.library.oregonstate.edu/xmlui/handle/1957/33886
Wernberg, T., Russell, B., Thomsen, M., Gurgel, F., Bradshaw, C., Poloczanska, E. Connell, S. (2011). Seaweed communities in retreat from Ocean Warming Current Biology 21: 1828-1832.
Zuccarello G.C., Critchley, A.T., Smith, J., Sieber, V., Lhonneur, G.B. (2006). Systematic and genetic variation in commercial Kappaphycus and Eucheuma (Solieriaceae Rhodophyta). Journal of Applied Phycology (2006) 18: 643-651doi 10.1007/s10811-006-9066-2.
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