Alexander Barrios

Reproductive cycle of the barred sorubim Pseudoplatystoma fasciatum (Linnaeus, 1766), in the upper delta of the Orinoco River, Delta Amacuro State, Venezuela

Pseudoplatystoma fasciatum represents one of the most important items in the continental fisheries of Venezuela. The great fishing pressure exerted on this species has decimated the populations in the Orinoco River Delta and other regions of the country. The current condition of the population in the delta region is unknown and information about basic biological parameters is unavailable. Hence, population and reproductive parameters of this catfish were determined in this region. Results showed that the size interval was from 30 to 105 cm total length (TL), generally smaller than the size range found in other regions of the country. The largest value for the gonadal index for females was 116, recorded in July. Size at maturity of 50% of females was 46.38 cm TL, a smaller value than others reported for the Orinoco River Basin. Maturation of oocytes was synchronous, showing a single total spawning per year. The capture of P. fasciatum was continuous throughout the year, including mature individuals during the reproductive season, suggesting a possible utilization of the delta region as reproductive site. A total of 61% of the individuals were below the minimum legal size, indicating deficient management of this fishery resource in the Orinoco River Delta.