Abstract
The knowledge of the juvenile distribution in fisheries is essential to better manage the fishingeffort on a stock. The exploration of a large dataset which covers 30 years of the purse seinefishery sampling enabled to study the spatio-temporal dynamic of the juvenile catches of theyellowfin and bigeye tunas. Results showed the existence of several areas of prime importance interms of catch and concentration in juveniles with seasonal variations. Thus, the south of thefishing ground (Cape Lopez) was fished during winter month and the north during summermonths (Cape Verde, Senegal y Mauritania). Offshore coastal zone and Gulf of Guinea werefished almost all along the year. This seasonal pattern is quite stable since the 90s but theproportion of juveniles in schools associated with floating objects tended to increase in bothspecies. This preliminary study opened the way for further research on this important componentof the fish stocks.