Maturation and spawning of Spratelloides gracilis Clupeidae in temperate waters off Cape Shionomisaki, central Japan

Abstract

The reproductive ecology of Spratelloides gracilis was investigated in the temperate waters off Cape Shionomisaki, central Japan. Cape Shionomisaki is located at the northern margin of the distribution range of this species. Females of S. gracilis with gonadosomatic index (GSI) Ն 4.0 were defined as mature based on the relationship between GSI and the histological maturity phases of their ovaries. More than 50% of females greater than 60 mm standard length (SL) were mature. Hatch dates of larvae and juveniles collected in the study area were determined by otolith daily ring counts and found to extend from April to November. The size at maturity of females (60 mm SL) and the spawning season of S. gracilis in the temperate waters off Cape Shionomisaki (April-November) was larger and shorter, respectively, than those in tropical waters in the western Pacific. The reproductive traits observed for S. gracilis off Cape Shionomisaki appear to be adaptive to northern temperate waters with seasonal changes in environmental conditions.

Mathematical Models’ Establishment of Hot-Air Drying forSpratelloides gracilis

“…The length of juveniles of Spratelloides gracilis ranges from 15∼40 mm (Shirafuji et al, 2007). Due to the higher content of calcium and fat, the traditional dried product of Spratelloides gracilis, named "Haiyan", has been one of the most important commercial clupeoids in Asia (Gwo et al, 2006).…”

Erratum: Reproductive biology of nocturnal reef fish Pempheris adusta (Pempheridae) in Okinawa Island, Japan

“…3d) The oocytes ranged from 402.6 to 656.8 µm in size (518.8±66.6 µm; Table 2). The yolk globules rapidly Shirafuji et al (2007). The GSI of the females in this stage ranged from 0.63 to 5.84 (2.67±1.43; Table 2).…”

Reproductive biology of nocturnal reef fish <i>Pempheris</i> sp. (Pempherididae) in Okinawa Island, Japan

“…Yolk globules became ap parent among the yolk vesicles, forming a layer on the periphery of the cytoplasm. This stage coincided with the primary yolk globule stage in Shirafuji et al (2007). The GSI of the females in this stage ranged from 1.10 to 1.93…”

“…Ovaries with more developed late yolk globule oocytes were considered to be mature. This stage includes both secondary and tertiary yolk globule stages in Shirafuji et al (2007). The GSI of the females in this stage ranged from 0.63 to 5.84 (2.67±1.43; Table 2).…”