Aspects of behavioral ecology of Sotalia guianensis in Sepetiba Bay, southeast Brazil

Abstract

Boat‐based surveys were conducted from August 2002 to July 2003 to study the activity patterns, spatial pattern of area use, and group characteristics of Sotalia guianensis in Sepetiba Bay, southeast Brazil. Predetermined routes covered the entrance and interior of the bay, resulting in 210 dolphin sightings during 3,300 km total effort. Data on activity were collected using scan group sampling with instantaneous recording after 5 min of observation. Dolphins were sighted more frequently in the entrance of the bay, where water is deeper, and salinity and transparency are higher, than in the interior of the bay, where the environment is more influenced by freshwater inputs. Foraging and feeding were the most frequent activities, and occurred predominantly between 0600 and 1000. Foraging and feeding peaked during ebbing, low, and flooding tides, while socializing predominated at high tide. Mean group size was larger in the interior of the bay and when seabirds were present. Large aggregations containing >100 individuals of Sotalia guianensis seen year‐round indicate that Sepetiba Bay is an important area for this species in coastal Brazil.

Epidemiological characteristics of skin disorders in cetaceans from South American waters

“…The pathogenic significance of diatoms is limited (Norman et al, 2004), if not nihil. Guiana dolphins with OPA were only observed during the winter in Sepetiba Bay, when mean sea surface temperature was 23.9°C (Flach et al, 2008). We suggest that 'orange film' and 'orange hue', 'orange patches' described in bottlenose dolphins from, respectively, the British Isles (Wilson et al, 1997) and California are equivalent to our OPA.…”

Report of the Working Group on Distribution, Habitat Characteristics and Preferences, and Group Size

“…(Lodi and Hetzel, 1998); in Baía de Paraty (23º18'S; 44º30'W) ca.100 individuals (Lodi, 2003b), and in Baía de Sepetiba (22º35'S; 44º03'W) with 200 individuals (Simão et al, 2000). In Bahia State, a group of 140 individuals was observed in Baía de Todos os Santos (Reis et al, 2006 20 ); in Santa Catarina State, at Baía Norte (27°23'S-27°35'S, 48°33'W-48°30'W), groups larger than 50 individuals were frequently recorded (Flores, 1999;Daura-Jorge et al, 2005). In the Paranaguá estuarine complex group sizes varied from 2 to 90 individuals , while in a nearby estuary groups were recorded with 2 to 60 individuals (Santos and Rosso, 2007).…”

“…Apparently the species is limited to depths of 50m (Fernandes, 2005). However, most sightings were recorded in water less than 25m deep (Bossenecker, 1978;Cremer, 2000;Di Beneditto et al, 2001;Edwards and Schnell, 2001;Flores, 2003;Lodi, 2003a;Azevedo et al, 2007;Santos and Rosso, 2007). S. guianensis is found as far as 36km offshore in Abrolhos Bank, an extension of the continental shelf with warm and shallow waters (Borobia et al, 1991;Rossi-Santos et al, 2006 The occurrence of the species is strongly associated with the presence of mangroves and estuarine regions (Borobia et al, 1991;Zanelatto, 2001;Santos, 2010).…”

“…Flores, 2003). Water temperatures vary from 13° to 32°C (Edwards and Schnell, 2001;Flores, 2003) respectively at the southern and northern ends of their range. The coastal habitat where the species occurs is subject to intense human activities such as fishing, boat traffic, oil exploration and urban development.…”

Coordinated feeding behavior of the Guiana dolphin, Sotalia guianensis (Cetacea: Delphinidae), in southeastern Brazil: a comparison between populations

“…In a recent study (TARDIN et al 2013a) observed that 94% of the groups have calves and/or juveniles. In the Sepetiba Bay, the population size is approximately 1,269 individuals (FLACH et al 2008), and calves are present in 80% of the groups.…”