Atherinella brasiliensis (Quoy & Gaimard, 1825) is a small estuarine fish that has yellow-green color with silvery longitudinal band below a black line. It has wide distribution in the western Atlantic, between Venezuela and the Rio Grande do Sul in Brazil. This work aims to contribute to the knowledge of A. brasiliensis by morphometric characterization of 56 individuals collected in the city of Salinópolis, coastal region of the state of Pará, northern Brazil, in September 2012. After the made relationships between external morphometric measurements, it was found that the best relationships are between total length (Ct) and the zoo lengths (Cz) and standard (Cp), characterized by the Pearson correlation coefficient (r), with value 0.99 in both relationships. We conclude that (1) A. brasiliensis has good morphometric relationships between the maximum total length measurement of and other external measures and (2) the equation made between the morphometric relationships satisfy the estimation of the size of this species.

Sampling date: 2016-09-12; Sea surface temperature (SST) = 30.3.7°C, Salinity = 27.