Bull. Jpn. Soc. Fish. Oceanogr. 80(3), Page 207-213, 2016   Relationship between the biomass of Japanese anchovy Engraulis japonicus and zooplankton density and salinity from 1978 to 2003 in Ise Bay Tsukasa Yoshida1†, Yuka Ohtake2, Shuichi Shiba2, Junpei Maeda1, Takeshi Hara1 and Teruaki Suzuki3 1 Japan Fisheries Science and Technology Association, 1-9-13, Akasaka, Minato, Tokyo 107-0052, Japan 2 Chateau Marine Survey Co., Ltd., 1-4-2　Katamati, Miyakojima, Osaka 534-0025, Japan 3 Graduate School of Environmental and Human Sciences, Meijo University, 1-501 Shiogamaguchi, Tempaku, Nagoya, Aichi 468-8505, Japan † E-mail: yosida.tu20@gmail.com Japanese anchovy Engraulis japonicas is one of the main species for fisheries in Ise Bay. The factors that contribute to changes in the Japanese anchovy biomass in the bay have not been identified. The ratio of the catch per unit effort of Japanese anchovy inside the bay to that outside the bay (biomass index) was calculated between 1978 and 2003 to reveal its interannual changes. The entry of Japanese anchovy into the bay along with the bay-mouth water was observed from 1978 to 1994 when the Kuroshio Current was offshore and a large meander occurred frequently; such a coincidence was not observed in the bay after 1995 when the Kuroshio Current was onshore and a large meander hardly ever occurred. From 1999 to 2003, we estimated the Japanese anchovy biomass each month using a quantitative echo sounder in the north-eastern waters of the bay, and investigated the zooplankton density. From July to September (i.e. the main fishing season), a positive correlation was found between the Japanese anchovy biomass and zooplankton density. This showed that the bay serves as a feeding ground for Japanese anchovy. Consequently, the influence of offshore water and prey availability are important for determining Japanese anchovy biomass in Ise Bay. Key words: Japanese anchovy, zooplankton, Ise Bay