Igarapés are small and dynamic water bodies that host a great diversity of Amazonian
ichthyofauna responsible for the trophic support of the aquatic biota. The objective of
this study was to analyze the spatiotemporal composition of ichthyofauna in peri-urban
streams in the municipality of Santarém, Pará. Collections were conducted in October
2016 (dry season) and April 2017 (wet season). Five streams belonging to four
watersheds were sampled. Each igarapé was sampled in four stretches with segments of
50 meters in length, blocked upstream and downstream with 5 mm mesh nets. Two
collectors conducted two hours of active sampling using "rapichés" and a manual trawl
net 1.2 meters in height, 7 meters long, and 5 mm mesh. Each sampling point, pH,
electrical conductivity, dissolved oxygen, and water temperature were measured.
Statistical analyzes were performed using the software PAST. A total of 9,193
individuals belonging to 62 species, 17 families, and 6 orders were collected. Fifty
species were recorded in both periods, of which 12 occurred exclusively in the wet
season and 12 in the dry season. The most abundant species were Hyphessobrycon
cantoi, Iguanodectes variatus and Copella callolepis. PERMANOVA showed a
significant difference in species composition between drainages (p=0.0001), with
indicator species correlated with the environmental variables of conductivity and pH.
Recognizing the composition of ichthyofauna in streams and their changes due to
abiotic factors under anthropogenic influence is a fundamental and necessary step for
establishing strategies and measures to protect and conserve the biodiversity of aquatic
biota.
|
