MEPS 591:185-197 (2018)  -  DOI: https://doi.org/10.3354/meps12272

ABSTRACT: Large aggregations of Nemopilema nomurai have occurred in the northern East China Sea, Yellow Sea and East Sea/Japan Sea since the end of the 20th century, and the Changjiang River mouth and its adjacent sea have been suspected as the source of these jellyfish blooms. Bohai Sea, China, located in the northwestern Yellow Sea, has had similar blooms that have had a major impact on local and regional fisheries, and as a consequence ecological studies were initiated in 2005 to further understand the ecology and dynamics of this jellyfish. In this paper, we present results of the spatiotemporal pattern of distribution and abundance of N. nomurai in Liaodong Bay (LDB) and the southern waters of Liaodong peninsula. These waters exhibit decreasing temperature and increasing salinity with depth. Warm and less saline waters are found in the river mouths, and relatively colder, more saline waters in the central part of LDB. The first appearance of N. nomurai metaephyrae or juveniles in LDB occurs in the northern inner coastal areas every year, clearly indicating that LDB is a habitat for N. nomurai polyps. As the season progresses, the jellyfish grow and mature, and their area of distribution expands to the whole LDB, or they are advected to the southern Liaodong peninsula. This is interpreted as a horizontal advection that facilitates completion of the entire N. nomurai life cycle in this area.

KEY WORDS: Nemopilema nomurai · Distribution · Advection · Breeding place · Jellyfish blooms · Liaodong Bay