Habitat use by southern right whales, Eubalaena australis (Desmoulins, 1822), in their main northernmost calving area in the western South Atlantic

Abstract

The subtropical and temperate coastal waters of the western South Atlantic are an important calving ground for southern right whales, Eubalaena australis. From 2002 to 2008, data on right whale distribution and habitat characteristics were collected in 14 bays along the coastline of Santa Catarina State, Brazil. Generalized linear models with a negative binomial error distribution were used to determine which environmental (beach morphotype, bay mouth width, bay inclination angle, northsouth and east-west wind components), and temporal (month and year) variables best explained the aggregation pattern of individuals. Our results suggested that both cow-calf pairs and adults unaccompanied by calves prefer bays with dissipative beaches, and that cow-calf pairs apparently avoid bays facing southeast during days of strong east-west winds. The number of sightings peaked in September and tended to increase over the study period. One particular embayment (Ribanceira beach) had considerably higher numbers of animals and may be considered a preferred spot in this calving ground. Our findings contribute to a better understanding of the species' habitat use and ecological requirements and should be taken into account if new management measures are implemented to further increase protection of southern right whales in the region.

Area usage estimation and spatiotemporal variability in distribution patterns of southern right whales, Eubalaena australis, of southern Brazil

“…Ribanceira/Ibiraquera and Itapirubá Sul/Sol were the most highlighted bays with higher concentration of whales in the northern area. Similar patterns of whales occurrence for Ribanceira/Ibiraquera bay were observed by Seyboth et al ().…”

“…Southern right whales commonly show some preference for particular bays within calving grounds (Burnell, ; Elwen & Best, ; Seyboth et al, ), as observed in our study.…”

“…Many studies have shown differences in patterns of distribution between right whales’ mother–calf pairs and unaccompanied adults (Best, ; Elwen & Best, ; Payne, ; Rowntree et al, ). However, Seyboth et al () suggest that in Brazilian breeding ground, similar environmental and behavioral conditions might influence the distribution of these two classes. Indeed, several preferential areas are occupied by both mother–calf pairs and unaccompanied whales, although the northern areas seem to be mainly occupied by mother–calf pair.…”

“…Southern right whales— Eubalaena australis (Desmoulins, 1822)—undertake seasonal migrations to the southern Brazilian coast during winter and spring to mate, give birth, and nurse their calves (Groch, Palazzo, Flores, Adler, & Fabian, ; Seyboth, Groch, Secchi, & Dalla, ). Whaling activities targeting right whales in Brazil began in the middle of the XVIII century (Elis, ).…”

“…Current records, however, are intermittent over the entire area (Lodi et al, ; Rossi‐Santos, Wedekin, & Souza‐Lima, ; Santos, Siciliano, Souza, & Piozzorno, ), and the highest concentration occurs along the southern coast (Greig, Secchi, Zerbini, & Rosa, ; Groch et al, ). The calving season occurs from July to November, with peak abundance in September (Groch et al, ; Seyboth et al, ).…”