Associations of large jellyfish distributions with temperature and salinity in the Yellow Sea and East China Sea

Climate change may contribute to the increasing frequency and intensity of jellyfish blooms around the world. To test the null hypotheses that distributions did not differ among species of jellyfish or according to temperature salinity, we sampled large jellyfishes using bottom trawl surveys during 2006–2007 in the Yellow Sea (YS) and East China Sea (ECS). The total biomass of large jellyfish in the YS was low in April 2006 in cool waters, increased with warming waters, peaked in early September 2006 (22,891 ± 25,888 kg km–2), and then decreased with cooling to minimal biomass during March 2007. During its peak early September 2006, Nemopilema nomurai was relatively eurythermal and distributed throughout the YS. Cyanea spp. occurred in warmer waters and attained maximum biomass in May 2007 in the ECS. Ulmaridae, which preferred colder temperatures, reached maximum biomass in October 2006 and occurred mainly in the central YS. Aequorea spp. usually occurred in colder waters, with maximum biomass in May 2007 mainly north of 30°N. Our analyses suggest that environmental preferences of the large jellyfish may enable prediction of jellyfish population sizes and distributions in Chinese waters, which is essential in order to address ecological problems caused by large jellyfish blooms in East Asia Waters.