Comportamento de pares fêmea-filhote de baleias-franca-austral, Eubalaena australis (Desmoulins, 1822) no litoral centro-sul de Santa Catarina

Abstract

The south central coast of Santa Catarina State is the most important breeding ground for southern right whales, Eubalaena australis, in Brazil. The aim of this study is to characterize the behavior pattern of mother-calf pairs that winter in this area, over ten breeding seasons (2003-2012). Land based observations were conducted from July to November, between 2003 and 2012, about six to seven times a week, between 6 a.m. and 5 p.m. Data were collected with the aid of binoculars Pentax 12x55 mm, compass, digital clock, and recorded in standardized field data sheets. Behavioral states (traveling, resting and playing) were recorded every five minutes and the frequency of events was recorded in each five minute interval. Traveling was the behavioral state that prevailed for both mother and calves, followed by resting and playing for mothers and followed by playing and resting for calves. Travelling and resting are important for mothers because they are less costly, since they need to use their energy to activities in which the survival of the species depends on, like giving birth, nursing and taking care of the calves. Playing is important for the calves to its motor development and its preparation for the migratory process. The most expressed events expressed by both mothers and calves were indefinite exposure, these being twice as high for the calves. Calves presented aerial behaviors at higher rates than their mothers, which denotes the importance of such behaviors in the aid of the development of motor skills coordination and in the muscles strengthening, improving resistance for migration. The aerial events rate of occurrence for mothers was generally lower, probably in an attempt to discourage the pranks conducted by the calves. These results reinforce the importance of the study area as a nursery ground for the species. The number of right whales is increasing in the area, as well as the potential for conflict with human activities. Understanding the behavioral patterns of southern right whale mother-calf pairs in Santa Catarina coast can serve as valuable tools for the formulation of management plans, contributing to the conservation of the species in the Brazilian coast.