Development and distribution of the early life stages of the longfin pearleye Benthalbella linguidens (Aulopiformes: Scopelarchidae) in the western North Pacific

The early life history and development of the scopelarchid Benthalbella linguidens was studied, based on 203 specimens ( from 5.3 to 89.7 mm in body length: BL) collected from Kuroshio, Oyashio waters and transition waters of the western North Pacific. The early life stages of B. linguidens are distinguished from those of other species of Benthalbella that inhabit the North Pacific by the characters of 62 - 64 myomeres in the larval stage and 26 - 28 anal fin rays in juvenile and transforming specimen. Larvae are elongate; notochord flexion begins at ca. 12 mm BL and is completed at ca. 15 mm BL. The fin ray complements are established at ca. 40 mm BL. The single transforming specimen ( 89.7 mm BL) that has peritoneal pigment was collected from transition waters. All larvae were collected from Kuroshio and transition waters from winter to early summer; however, the size of larvae in Kuroshio waters was apparently smaller than that in transition waters, with ranges of 5.3 - 32.4 mm BL ( mean 17.1) and 15.3 - 35.3 mm BL ( mean 27.5), respectively. Juveniles were distributed in transition and Oyashio waters and were absent in Kuroshio waters, where adults are commonly distributed. These occurrences of larvae and juveniles in the western North Pacific indicate that B. linguidens spawns in Kuroshio waters in winter and uses transition waters as nursery grounds.