[Marine ] Oder Atheriniformes Family Atherinidae(Silversides) Sumatran silverside Hypoatherina valenciennei(Bleeker, 1854) Max length/15.0 cm TL Korean name/Saek-jul-myeol(색줄멸) Japanese name/ トウゴロウイワシ (Tōgorō iwashi) Chinese name/凡氏下银汉鱼 D1/spines 4–7, D2/spine 1 soft rays 8-10. A/spines 1, soft rays 10-13. Pelvic fin/spine 1, soft ray 5. Pectoral fin/spine 1, soft ray 14~16. Gill rakers/20~26. Lateral scale/40~46. Vertebrae/38~44.
Distribution; Indo-West Pacific/Korea (Pohang, Busan, Jeju Island) Japan, Taiwan, Hong Kong, Philippines, Guam, Vietnam, Gulf of Thailand, Singapore, Indonesia (Java Island), New Britain, Papua New Guinea, Solomon Islands, General; Body rubust and less slender than other species of Hypoatherina. Head small and triangular. Head almost cylindrical, posterior part of the gill is severely compressed. Dorsal profile straight with slight slope both toward head and tail. The head is 2.7 times of eye diameter. Belly slightly rounded. Eyes very large, reaching twice the length of the snout. The first dorsal fin is located in the middle of the body, and the second dorsal fin is separated far from the first dorsal fin. The origin of the anal fin is far anterior to the origin of the second dorsal fin. Pelvic fin starts at the posterior end of the pectoral fin. Anus located in the middle of pelvic fin. Margin of caudal fin deeply forked.
The maxilla and mandible equal in length, and the rear end of the maxilla reaches anterior margin of eye. Premaxilla long and obliquely directed. Upper jaw extremely protractile. Dentary with very few teeth. Small teeth in anterior maxilla, vomer, and palatine. Tongue(basihyal/舌骨) often with teeth around edge. No small spine on above area of eye, so the surface is smooth. A groove on the outer edge of preopercle below posterior margin of eye Abdomen smooth without keel. There are no lateral lines. Body covered with weak ctenoid scales. Body scale large, dorsoventrally elongated with circuli on anterior half, with posterior edge rounded and margins of scales crenulated. Small processes on anterior edge of each scale on sides of body. no scales on the head except for the gill cover. Sensory pores on head large.
Colors are described in various ways in each resource, making it confusing. By observing several photos, it can be explained as follows. Fresh individuals are blue-green or light greenish-yellow gray on the dorsal side and light bluish white on the ventral side. On the central axis of the body, there is a wide horizontal band from the base of pectoral fin to the base of the caudal fin, which is light blue in color and has a very deep blue thin stripe right above the band. In some cases, a yellow line is visible instead of this thin blue line. The tip of the snout is black. In individuals that have died for some time, the horizontal band in the middle of the body becomes a distinct silvery band, and in the fixative solution, the entire body becomes light yellow and the band becomes dark brown or black. Small fish that lives in groups in the reefs around the coast The spawning period is May-July, and the eggs are with sticky filaments, so they attach to seaweed. They feed mainly on zooplankton
|