Molecular and Morphological Identification and Seasonal Distribution of Eggs of Four Decapterus Fish Species in the Northern South China Sea: A Key to Conservation of Spawning Ground

摘要: Although species of Decapterus form important pelagic fisheries in the northern South China Sea, information on their spawning grounds is limited because identification fish eggs based morphology difficult. We identify four (D.macrosoma, D.maruadsi, D.macarellus, and D.tabl) with DNA barcodes from fishery resources surveys Spring Autumn 2018 Xisha islands, later summer-Autumn 2019 along continental shelf describe egg morphology. Of 1405 obtained COI sequences, 81 were successfully attributed to species; each are spherical, have a smooth chorion narrow perivitelline space, can be partly differentiated by diameter, melanophore drops oil globule, notum embryo. Seasonal distributions reveal grounds, that D.maruadsi located mainly off Pearl River estuary spring; D. maruadsi rarely co-occur those D.macrosoma. Spawning D.macrosoma probably further south, where water temperature salinity higher. periods these overlap slightly. habitat has been lost, season extended. Identification using assist traditional morphological approaches. Spatial temporal used for improved conservation management Sea.