World Aquaculture Magazine - June 2021

28 JUNE 2021 • WORLD AQUACULTURE • WWW.WA S .ORG aquaculture, instead of reducing it to overlooked footnotes at the bottom of tables, stating “excludes aquatic mammals, crocodiles, alligators and caimans, seaweeds and other aquatic plants,” it would help to correct some misconceptions, wrong interpretations of its data and avoid reaching incorrect conclusions (Chopin 2012). Seaweed aquaculture is estimated to have produced 32.4 MMT fresh weight in 2018 for a value of US$13.3 billion (FAO 2020). This represents 51 percent of the total production of marine and coastal aquaculture. Eight seaweed genera provide 97 percent of the world seaweed mariculture production (Table 4). Two seaweed genera are the most-produced organisms in mariculture in the world (Table 5). Seven of the top 17 major organisms produced in world mariculture are seaweeds. Seaweeds were the first group of organisms to pass the 50-50 percent farmed/wild harvest global threshold 50 years ago in 1971, and presently represent 97 percent of the world seaweed supplies (i.e., wild seaweed fisheries provide only 3 percent). How much of this is known in the western world? Not much, because more than 99 percent of the seaweed mariculture production is concentrated in nine East and Southeast Asian countries and territories (depending on the status one grants Taiwan; Table 6). There is exciting, renewed interest in seaweed mariculture in the western world. It has been triggered by 1) their cultivation in integrated multi-trophic aquaculture (IMTA) systems in which they are the key component to recover dissolved inorganic nutrients, 2) the emerging understanding of the ecosystem services they provide and 3) the development of novel uses and new applications. Within the last 5-6 years, seaweeds seem to have suddenly become the topic of the kind of hype and fantasies reviewed earlier for animal aquaculture in its new geographies by people who are (re-)discovering them. They are waving them around as the panacea to all our problems: climate change, fuel crisis, bovine flatulence, world decarbonization and a cure for all kinds of aches, pains and diseases. In some cases, it looks and sounds very much like the reincarnation of the Snake Oil Salesmen of the California Gold Rush Era who have become “Seaweed Oil Salespersons of the Internet.” These are often people who, in fact, have never studied, touched, grown or harvested seaweeds, except during the three- minute video for a social media scoop. Many seaweed professionals in seaweeds’ new geographies are involved in pilot projects that extend not only to the Tropics but also across the North Atlantic/Pacific and Arctic areas of the world (Araújo et al. 2021, UNGlobal Compact 2021). We recall that the last time there was such an infatuation with seaweeds was in the 1970s as a consequence of the world oil crises of 1973 and 1979, when biogas (before it became biofuels) TABLE 4. The eight genera providing the majority of the world seaweed mariculture production with “other algae” combined to make the total world seaweed mariculture production in 2018. Red seaweeds Eucheuma spp. 9.4 (29.0) Kappaphycus spp. 1.6 (4.9) Gracilaria spp. 3.4 (10.7) Porphyra/Pyropia spp. (nori) 2.9 (8.9) Total red seaweeds 17.3 (53.5) Brown seaweeds Saccharina japonica (kombu) 11.4 (35.3) Undaria pinnatifida (wakame) 2.3 (7.2) Sargassum spp. 0.3 (0.8) Other Phaeophyceae 0.9 (2.8) Total brown seaweeds 14.9 (46.1) Other algae 0.2 (0.4) Total world production 32.4 (100) Numbers are in million metric tons live weight (FAO 2020); numbers in brackets are percentages. TABLE 6. Seaweed mariculture production by major producers. China 18.5 (57.1) Indonesia 9.3 (28.8) Republic of Korea 1.7 (5.3) Philippines 1.5 (4.6) Democratic People’s Republic of Korea 0.5 (1.7) Japan 0.4 (1.2) Malaysia 0.2 (0.5) China - Taiwan 0.1 (0.2) Vietnam 0.0 (0.1) Total Asian seaweed production 32.2 (99.5) Zanzibar, United Republic of Tanzania 0.1 (0.3) Chile 0.0 (0.1) Other producers in the world 0.1 (0.1) Total world seaweed production 32.4 (100) Numbers are in million metric tons live weight (FAO 2020); numbers in brackets are percentages. TABLE 5. Major organisms produced in world mariculture in 2018. Saccharina japonica (kombu) 11.4 Eucheuma spp. 9.4 O ysters 5.8 Penaeus vannamei (whiteleg shrimp) 5.0 Ruditapes philippinarum (Manila clam) 4.1 Gracilaria spp. 3.4 Porphyra/Pyropia spp. (nori) 2.9 Salmo salar (Atlantic salmon) 2.4 Undaria pinnatifida (wakame) 2.3 Scallops 1.9 Kappaphycus spp. 1.6 Mussels 1.6 Sinovovacula constricta (Chinese razor clam) 0.9 Penaeus monodon (giant tiger prawn) 0.8 Anadara granosa (blood cockle) 0.4 Sargassum spp. 0.3 Apostichopus japonicus (Japanese sea cucumber) 0.2 Numbers are in million metric tons live weight (FAO 2020); brown seaweeds in brown font, red seaweeds in red font.