During the months of March to August 2019, the study was carried out to identify the spawning areas in the middle basin of the Nanay River by relating the embryonic development of fish eggs and the speed of the river current, the sampling they were done fortnightly and three times both in the rising and emptying season, in the superficial layer and center of the river, then the state of embryonic development and the time required according to the reports generated36 were analyzed. The results indicate that during the entire There is reproduction every year, but it is more intense during the flood season. The hydrographic system of the Allpahuayo-Mishana National Reserve and the middle basin of the Nanay River still conserve the arboreal and shrubby plant formations, despite the impact that is produced in their environment. It has been determined that spawning takes place in the section f...