Instituto Boto Cinza Guiana dolphin distribution between 2005-2007 in Sepetiba Bay, Brazil

Projeto Boto Cinza

Dataset credit

Projeto Boto Cinza


Primary contact Leonardo Flach Projeto Boto Cinza, Instituto Boto Cinza
Data entry Connie Kot



Between August 2005 and July 2007, 376 Guiana dolphin (Sotalia guianensis) encounters were documented in Sepetiba Bay.
For the purpose of this study all dolphin sightings were classified as groups or aggregations. Groups (N = 268, x = 20, range =
1–90) consisted of dolphins in apparent association usually engaged in the same behaviour and moving in the same direction.
Aggregations (N = 108, x = 204, range = 100–450) consisted of temporal association of numerous groups gathered in an
area, totalling several hundred individuals usually engaged in the same behavior but not necessarily moving in the same
direction. Guiana dolphin groups and aggregations differed significantly in behavioral activity, spatial and temporal distribution
and age composition. Most aggregated dolphins were engaged in foraging/feeding activities and primarily located at
the interior of the bay, and also, aggregations were more likely recorded during morning hours and had more neonates and
calves present when compared to groups. The plotted global positioning system (GPS) records of aggregations formed two distinct clusters of distribution
within the bay, indicating potential areas where conservation strategies could be implemented.


The objective of this study was to investigate the occurrence
of Guiana dolphin aggregations regarding their seasonal,
diel and spatial distributions; behavioral activities, age
composition and the environmental parameters measured
during their occurrence in Sepetiba Bay.

Supplemental information



Dias, L.A., D. Herzing, and L. Flach. 2009. Aggregations of Guiana dolphins (Sotalia guianensis) in Sepetiba Bay, Rio de Janeiro, south-eastern Brazil: Distribution patterns and ecological characteristics. Journal of the Marine Biological Association of the United Kingdom. 89: 967-973.



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Attributes described below represent those in the original dataset provided by the provider.
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Attributes in dataset

Attribute (table column)Description
oidUnique ID number (generated by SEAMAP)
surveySurvey code
obs_dateObserved date
obs_timeObaserved time
latitudeLatitude of observation
longitudeLongitude of observation
obs_countObserved count
sp_obsSpecies observed
sp_tsnSpecies ITIS TSN
Marine mammals372
Sea turtles0
Rays and sharks0
Other species0
Non spatial0
Non species0
Date, Begin2005-08-11
Date, End2007-07-30
Temporal prec.111111
Latitude-23.06 - -22.93
Longitude-44.03 - -43.71
Coord. prec.6 decimal digits
Data typeAnimal sighting
Traveled (km)0
Contr. through
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GBIF (via DOI)
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