Artificial reproduction and reproductive parameters of the internally inseminated driftwood catfish Trachelyopterus galeatus (Siluriformes: Auchenipteridae)

The driftwood catfish Trachelyopterus galeatus (Linnaeus 1766) is widely distributed in the Sao Francisco basin in Brazil, having internal fertilization as its reproduction hallmark. Since there are no studies on the artificial reproduction of T. galeatus, the aim of the present study was to induce spawning by hypophysation and to determine the reproductive parameters for this species. Thus, T. galeatus adults (12 of each sex) were treated with Cyprinus carpio pituitary homogenate (CPH) and 8 of the 12 females (67 %) responded positively to the treatment. The stripping of oocytes was carried out at 24 degrees C, 14 h after the application of CPH, and the average fertilization rate was 60 %. The number of stripped oocytes was 351 +/- 5 oocytes g(-1) with average egg diameters of 2.3 +/- 0.1 and 3.3 +/- 0.1 mm before and after eggs hydration, respectively. The oocytes of T. galeatus were opaque, light yellow, demersal, adhesive, and covered with a jelly coat. Data regarding egg production were also recorded for T. galeatus with an average of 8.2 +/- 1.4 (%) for the stripped oocyte index and 3,163 +/- 1,011 oocytes for total fecundity. The initial and final embryo survival rate was of 2,491 +/- 953 and 1,527 +/- 670 embryos, respectively. Larval hatching took up to 127 h after fertilization at 24 degrees C where the larvae presented a mean total length of 4.2 +/- 0.1 mm. The findings obtained for T. galeatus demonstrated the success of artificial reproduction and the first description of reproductive parameters such as fecundity, embryo survival rate, and egg biology for this species.