The phytoplankton community was evaluated in 21 samples collected in seven sites in the Itaya river basin. In total, 70 species belonging to 40 genera, 21 families and 6 divisions were identified. The most abundant group was Bacillariophytas (51%), followed by Chlorophytas (31%), Euglenophytas (11%), Cyanophytas (5%), and others (2%) corresponding to Xanthophyta and Chrysophyta. The best represented species were Surirella ovalis, Navicula sp and Pinnularia sp. For this ecosystem, the density was between 100 to 13 000 ind/l-1 (individuals per litre) out of a total of 24 500 ind/l-1, with a richness of 11 to 27 species and an abundance of 23 to 55 individuals. The analysis of diversity according to Shannon-Wiener was from 7.26 to 25 units of effective species, with an equity of Pielou of 0.84-0.97, which indicates that the populations were homogeneous. Regarding the similarity index, it sh...

Se evaluó la comunidad fitoplanctónica en 21 muestras colectadas en siete lugares de la cuenca del río Itaya. Se identificaron 70 especies pertenecientes a 40 géneros, 21 familias y 6 divisiones. El grupo de mayor abundancia fue Bacillariophytas (51%), seguida de Chlorophytas (31%), Euglenophytas (11%), Cyanophytas (5%), y otros (2%) correspondientes a Xanthophyta y Chrysophyta. Las especies mejor representadas fueron Surirella ovalis, Navicula sp y Pinnularia sp. Para este ecosistema, se registró una densidad entre 100 a 13 000 ind/l-1 (individuos por litro) de un total de 24 500 ind/l-1, con una riqueza de 11 a 27 especies y una abundancia de 23 a 55 individuos. El análisis de diversidad según Shannon-Wiener fue de 7.26 a 25 unidades de especies efectivas, con una equidad de Pielou de 0.84-0.97, lo que indica que las poblaciones fueron homogéneas. En lo que se refiere al índic...

Paiche (Arapaima sp.) is an emblematic species of the Peruvian Amazon, yet sustainable production remains constrained by the limited availability of fry in captivity. This study aimed to evaluate the partial replacement of Artemia sp. by Moina sp. during the live-feeding phase and the effect of early weaning onto a commercial trout diet on growth, survival, and digestive system histology. The 37-day feeding trial was conducted with six treatments in triplicate, defined by three weaning sizes (3, 3.5, and 4 cm total length) and two live-feed regimes (100% Artemia sp. or 50% Artemia sp. + 50% Moina sp.). All groups were weaned onto the same commercial diet. Results showed that replacing 50% of Artemia sp. with Moina sp. did not compromise initial performance. However, fry assigned to weaning at 4 cm showed reduced growth while remaining exclusively on live feed, suggesting limitations of t...