Presence of the Neotropical Otter in the Cubatão do Sul River, Santa Catarina, Brazil

Abstract

This work represents an analysis of the presence of Lontra longicaudis in the Cubatão River, Santa Catarina, Brazil. The influence that temperature and precipitation can have on the collection of excrements of the species is examined. The composition of the diet is determined by the collected excrement. From 2006 to 2007, 255 feces were collected using rafting boats in the study area, which is characterized by strong rapids and waterfalls. Precipitation and temperature data from January 2006 to September 2007 were obtained. The Kruskal-Wallis test was used to determine the seasonal difference between samples of items consumed by otter. The Chi-square test was used to evaluate the difference between the collected and expected data regarding the temperature and precipitation. The relationship between average monthly temperature and rainfall, and the frequency of occurrence of food items was evaluated using Spearman coefficient. The fish group was the most abundant in the otters diet, representing 70% of the total, followed by crustaceans (23%) and mammals (4%). Birds accounted for 3%. Differences in items consumed by otters in the Cubatão do Sul River were observed between the hottest and coldest months. The number of excrement collected was lower than expected during rainier periods, demonstrating the care that must be taken in research planning. The presence of the otter in the Cubatão River basin can be important for both environmental and economic management of the region, especially as it represents an important source of water for thousands of people.