Introduction

As seaweed consumption has increased in the last several decades, seaweed mariculture has filled the gap between wild stock harvest and the present demand. Ancient records show that people collected seaweeds for food starting in about 2500 BP in China (Tseng 1981), and 1500 in Europe (Critchley and Ohno 1998). Presently, the wild harvest of seaweeds is about 1.8 m tonnes y-1, mainly brown seaweeds used for alginates (FAO 2009). In Japan, China, and other Asian countries, where seaweeds have long composed an important part of the human diet, seaweed farming is a major business and over 90% of the seaweed production is from farming for human consumption. Since 1970, the culture of seaweeds has increased at ~8% per year (FAO 2009). Seaweed production from farming nearly doubled from 8.8 to 15.9 million tonnes from 1999 to 2008, with a value of US$7.4 billion (FAO 2010). Most of the world seaweed supply comes from aquaculture and seaweeds were the first to pass the 50% farmed/wild harvest threshold in 1971, compared to fish aquaculture that will exceed the 50% threshold by 2012 (Chopin 2012). About 99% of the farmed production is in Asia and over 70% of the production (10.9 million tonnes) is in China, followed by Indonesia, the Philippines, South Korea, and Japan. Chile is the most important producer outside of Asia with a production of 90 000 tonnes y-1 of wild harvested seaweeds. Table 10.1 illustrates the production, value, price and the three main producing countries for the six most important seaweed genera that are grown in aquaculture systems. Brown seaweeds compose about 64% of the production (67% of the value), reds about 36% (33% of the value), and greens, with ~99% being produced by Asian countries, 0.2% of the production and value (Chopin and Sawhney 2009). There has been a rapid increase in production in the last decade, especially of reds and browns (Fig. 10.1). The largest production (4.6 million tonnes; Table 10.1) is from Saccharina japonica (previously Laminaria japonica; or kombu in Japan or haidai in China), mainly in China. Korea grows mainly Undaria pinnatifida (wakame) with 1.8 million tonnes annually and Pyropia (previously Porphyra, or nori), while Japan focuses mainly on Pyropia.