Base on the fishing account data derived from Nan-Fan Ao fishing market, theaccumulating production during Jan.-Oct., 2005 reached to 74,754 tons about 1.61times more than that of 46,343 tons in 2004, and they are two of the most importanteconomic fishes and can be caught all the year round in Taiwan. Therefore, the mainpurpose of this project planed is try to realize the distribution status and the abundanceof the mackerel and scad larvae in the waters of Taiwan, and its geographic and spacialdistribution whether various with the seasonal changes or not are also investigated. Themethods used in this study are the CTD was used for measuring water temperature andsalinity (Seabird-19 with 637 style), and the casting depth was at 500 m in depth. Thelarval fishes were conducted and sampled by Bongo net at depth of 100 meters Thevelocity of sampling Bongo net upward was set at 20 m/min. And all the sampling larvalfishes were stored on the bottle with 10% formalin and 95% alcohol respectively for thefuture analysis. The size of each of the larval fish schools was served as a cylinder andmeasured by the estimation equations. All the data collected and analyzed are given tothe government as a mackerel and scad fishery police reference. A total of 53 operatingstations with Bongo net at vertical speed of 20 m per minute to collect the larvae, CTDare also planed to conduct to realize the relationship between the larvae and fishingground environment in the forthcoming year.