Sampling by vertical net from 30m to surface.
For Ohtsuka & al. (2005, p.97) this species belongs to alcoki-group. According to the authors this species can be regarded as the northernmost of the species-group. However, this new species has never been recorded before nor since its discovery in 1979, suggesting that it may not be a natural inhabitant of the region. An possibility is that a temporary pseudo-population extended to Shimizu via the Kuroshio Current extension from the southern populations originally inhabiting tropical/subtropical areas of East Asia. Another possibility is that the new species could have introduced from Indo-West Pacific area via ballast water (Shimizu is an important harbour frequented by many container and bulk ships from all over the world. This sporadic occurrence in Japanese waters suggests that is a native species that is difficult to collect either to its low numbers , a restricted distribution near the surface or bottom, or a limited occurrence in time due to patterns of diapause egg production (see Grice & Marcus, 1981; Madhupratap & al., 1996; Marcus & Lutz, 1998; also see for phytoplankton: S. Ribeiro & al., 2011).