Variação Temporal De Larvas De Clupeiformes (Pisces, Teleostei) Em Um Lago De Várzea No Baixo Amazonas, Pará, Brasil / Temporal Variation of Clupeiformes Larvae (Pisces, Teleostei) in Várzea Lake in the Lower Amazon, Pará, Brazil

Abstract

Maicá lake is located in várzea area, in the floodplain of the low stretch of the Amazon River, being considered a fishy environment that guarantees food and income for several communities and surrounding residents. The objective of the study was to know and expand information about the occurrence and temporal distribution of Clupeiformes larvae in Maicá lake, Santarém, Pará, located five km from the city of Santarém, in the Lower Amazon region. 12 monthly collections were carried out during 2015, with sampling cycles during the day and night, distributed in nine georeferenced stations. The biological material was collected by means of horizontal dragging on the subsurface of the water column, with the aid of a 300 μm conical plankton net. To check for possible differences in larval density between the sampling months, analysis of variance (ANOVA One-Way) was used. A total of 2,191 individuals belonging to the order Clupeiformes were captured, distributed in three families, four genera and seven species. The larvae density varied and differed between the months of the year, with the highest value recorded in the month of October, indicating the end of the low season the period of greatest reproductive activity of this group of fish in the region, that is, under conditions of high temperatures and low levels of dissolved oxygen in the water. The information demonstrates the relevance of Maicá lake as a nursery and development area for larvae of Clupeiformes, highlighting the importance of maintaining the integrity of this aquatic ecosystem and proposing conservation actions to maintain the populations of these species that currently occupy this source.