Tuna fishery by pole and line or baitboat was developed many years ago by Japanese fisherman. And latter incorporated by Portuguese and Spanish among others. The method consists of fishing with pole and line on tuna schools that are attracted and kept to the boat with the aid of constant thrown of live bait in the sea. This technique was firstly introduced in Brazil the seventies and nowadays is one of the most lucrative fisheries of Brazil. The main objective of this work was to identify the species which are used as live baits in this kind of fishery their main areas of capture, as well as to estimate the CPUE of the industrial fleet , on the bait stock, during the harvest period of 1998/99. Results showed that seven species of Clupeidae and Engraulidae families are used as bait, being Sardinella brasiliensis the most important specie, representing 49% in weight of total caught. Most of the biomass was captured within well delimited intervals of temperature (25°C to 28°C) and depth (5 to 15m), on the Porto Belo region. CPUEs ranged between 261,15 e 1654,3 Kg /day of bait fishing.