Distribution of final stage phyllosoma larvae and free-swimming pueruli of Panulirus japonicus around the Kuroshio Current off southern Kyusyu, Japan

Abstract

The distribution of the phyllosoma larvae and free-swimming pueruli of the Japanese spiny lobster Panulirus japonicus (von Siebold, 1824) has been studied off the south coast of Kyusyu Island. From 1992 to 1995, four research cruises were conducted on board the R.V. “Yoko-maru”. Cruises were mainly carried out over the new moon period between June and August along transect lines that cross the Kuroshio Current. In total, 89 later stage Form F phyllosoma (body lengths ≥20 mm) and 43 free-swimming pueruli of P. japonicus were caught; 94.4% of the later stage phyllosoma larvae were in the final stage. The phyllosoma were distributed widely in and south of the Kuroshio Current, where high-salinity (34.8) water exists at depths below about 80 m. Highest densities of the final phyllosoma larvae were observed in or near the Kuroshio Current, and molting to the puerulus stage also occurred in the same area. Free-swimming pueruli were mainly sampled in and north of the Current. It is suggested that the pueruli of P. japonicus swim across the Kuroshio Current to settle in coastal areas.