Implications of meso-scale eddies caused by frontal disturbances of the Kuroshio Current for anchovy recruitment

This paper discusses the implications of the meso-scale eddies, which are c aused by frontal disturbances of the Kuroshio Current, for larval transport , distribution and food availability for Japanese anchovy, Engraulis japoni cus (Houttuyn). It is a ubiquitous feature of the Kuroshio Front that wave- like meanders, with wavelengths of 100-400 km, generate cyclonic frontal ed dies off the Pacific coast of the island of Japan. These eddies are likely to affect larval transport and the survival of the coastal spawning fish su ch as anchovy in the Kuroshio region by possibly moving coastal water offsh ore to the frontal region. With this in mind, a frontal eddy was tracked from 18-23 May 1994 in the En shu-nada Sea, where one of large spawning grounds of anchovy was found. Int ensive transect surveys across the eddy were made to collect anchovy eggs a nd larvae simultaneously with prey organisms e.g. naupliar and copepodite c opepods. These surveys showed that anchovy eggs and larvae hatched in the c oastal water of the Enshu-nada Sea were entrained into the frontal eddy and transported along the Kuroshio front, possibly recruiting to coastal nurse ries in the Enshu-nada Sea. In addition, the upwelling of nutrient-rich wat er in the vicinity of this cyclonic eddy enhanced primary production and su bsequent copepod production, providing potentially favourable conditions fo r the feeding and growth of the anchovy larvae entrained in the eddy. (C) 2 000 International Council for the Exploration of the Sea.