Impacts of ocean warming on supply of the commercially important seaweed species, Pyropia, in Korea

Abstract

South Korea’s aquaculture industry is dominated by seaweed farming. However, seaweed farming faces future challenges as it is highly vulnerable to environmental changes. Seaweeds are sensitive to temperature changes which can cause negative effects on metabolic activities, such as growth rates. Temperatures increasing up to a species’ optimal temperature promote growth, however, beyond that threshold results in declining growth rates and even decay. Ocean warming due to anthropogenic climate change poses a problem to seaweed farms as sea surface temperatures (SST) are projected to increase by up to 1.5℃ by 2050 and to 4℃ by the end of century under high emission scenarios. This paper applies biological theory and economic concepts to provide an estimation of how changes in the growth rate of the economically important seaweed species, Pyropia, will affect supply and revenue for this species under low and high emission scenarios. This study reveals that total supply of Pyropia will decrease by around 15~17% by 2050 and 18~72% by 2100 under low and high emissions, respectively. At a regional scale, Korea’s South Sea could suffer severe losses in supply for all emission scenarios, while some regions in the West Sea will experience an increase in supply through to 2100 with low emissions, and by 2100 under a high emission scenario. Changes in the supply of Pyropia will correspond to a decrease in total seaweed revenue by roughly 12% in 2050 for both high and low emissions, and up to 50% in 2100 with high emissions.