Yellowstripe scad

Description

The yellowstripe scad,Selaroides leptolepis,(also known as the yellowstripe trevally,yellow-banded trevally,smooth-tailed trevally,slender-scaled trevally and slender trevally) is a species of small inshore fish in the jack and horse mackerel family Carangidae,and the only member of the genus Selaroides.The yellowstripe trevally is distributed throughout the tropical waters of the Indo-West Pacific region,ranging from the Persian Gulf in the west to Vanuatu and New Caledonia in the east.The species is distinguished by its prominent lateral yellow band,and differs from the scads of the genus Selar in having a smaller eye and different dentition.The yellowstripe scad reaches a maximum recorded length of 22 cm,however is normally encountered at sizes less than 15 cm.Phylogenetic studies indicate the yellowstripe scad is closely related to the scads of the genus Selar,although its exact placement in the family Carangidae is less well agreed upon.A schooling species that predominantly inhabits inshore waters,the yellowstripe scad is a predatory fish,taking crustaceans,small fish and a variety of other planktonic prey.Feeding occurs at different times of the day and night throughout its range.The species reaches sexual maturity at around 8–13 cm,with spawning in India shown to occur in two peak periods between January to April and July to October.The yellowstripe scad is an important commercial species,with between 113,000 t and 195,000 t reported worldwide between 1990 and 2010.The species is predominantly harvested with trawls,however is also taken with smaller traditional nets.The yellowstripe scad is marketed fresh,frozen,as a dried fish snack as well as several novel ways including fish powder,surimi and burgers.The yellowstripe scad is a small species,attaining a maximum length of 22 cm,but is more common at lengths less than 15 cm.The species has a body shape typical of many scads,with a compressed elongate,oblong body with the dorsal and ventral profiles equally curved.There is a fairly well developed adipose eyelid on the latter half of the eye.The dentition of the yellowstripe scad is one of the diagnostic features of the species,with the upper jaw and mouth being devoid of any teeth while the lower has a single series of fine villiform teeth.The dorsal fin is in two parts;the first having 8 spines and the second 1 spine and 24 to 26 soft rays.The anal fin has 2 detached spines followed by 20 to 23 soft rays.In one recorded case these two spines were not present.The soft dorsal and anal fins both have scaly basal sheaths.The pectoral fin is falcate and doesn't reach the junction of the curved and straight sections of the lateral line.The pectoral girdle has no groove,and is another defining characteristic.The anterior curve in the lateral line is moderate,with the straight section containing 13 to 25 scales and 24 to 29 small scutes.The breast is completely scaled.There are 40 to 46 gill rakers in total and 24 vertebrae.The yellowstripe scad is a metallic blue to blue-green colour above grading to a silvery white below with a characteristic broad yellow stripe extending from the upper margin of the eye to the caudal peduncle.A black opercular spot is prominent and often extends onto the shoulder.The dorsal,anal and caudal fins are pale to dusky yellow,the pelvic fins are white and the pectoral fins hyaline.