1Kanagawa Prefectural Fisheries Research Institute, Miura, Kanagawa 238-0237, 2Laboratory of Aquatic Molecular Biology and Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan
Fish eggs and larvae were collected on August 21 and 22, 2002 with a Norpac net (φ=45 cm) by a horizontal haul on the surface and vertical one from the surface to 200 m depth in the Pacific Ocean around the Kurose Sea Hole, north of Hachijo in the Izu Islands. Among the samples thus collected, 3,394 eggs and 17 larvae were regarded as those of alfonsino according to their morphological characters. Subsequent detailed species identification was carried out for 63 eggs and 17 larvae based on RFLP patterns and nucleotide sequences of the mitochondrial 16S rRNA gene. PCR successfully amplified DNA fragments of 577 bp in the 3´ site encoding the 16S rRNA gene for 53 eggs and 11 larvae, which were all identified as Beryx splendens. However, DNA fragments were not amplified for 10 eggs and 6 larvae due to poor DNA extraction. The spatial distribution patterns of B. splendens eggs discriminated into three different developmental stages suggested that this fish spawns its eggs near the seabed and thereafter moves to the sea surface as development progresses.