Modelling habitat use by the Guiana dolphin, Sotalia guianensis , in south‐eastern Brazil: Effects of environmental and anthropogenic variables, and the adequacy of current management measures

2020 ◽  
Vol 30 (4) ◽  
pp. 775-786 ◽  
Author(s):  
Rodrigo H. Tardin ◽  
Israel S. Maciel ◽  
Mariana A. Espécie ◽  
Gabriel Melo‐Santos ◽  
Sheila M. Simão ◽  
...  
Keyword(s):  
Habitat Use ◽  
Current Management ◽  
Sotalia Guianensis ◽  
South Eastern ◽  
Management Measures ◽  
Eastern Brazil ◽  
Guiana Dolphin

Individual identification and habitat use of the estuarine dolphin Sotalia guianensis (Cetacea: Delphinidae) in Cananéia, south-eastern Brazil, using video images

2008 ◽  
Vol 88 (6) ◽  
pp. 1199-1205 ◽  
Author(s):  
L.V. de Oliveira ◽  
E.L.A. Monteiro-Filho
Keyword(s):  
Habitat Use ◽  
Individual Identification ◽  
Dorsal Region ◽  
Extensive Area ◽  
Sotalia Guianensis ◽  
South Eastern ◽  
Dorsal Fin ◽  
Video Images ◽  
Eastern Brazil ◽  
Estuarine Dolphin

Individual identification using Hi8 video images was tested on the population of estuarine dolphins, Sotalia guianensis that inhabit the Cananéia estuary, south-eastern Brazil. Between June 2001 and August 2002, 25 different dolphins were identified by nicks on the dorsal fin (80%) and by the association of cuts and scratches on the dorsal fin and the body's dorsal region (20%). The existent marks were used to create an identification key to ease the matching between dolphins. The animals were present on 100% of the sampled days, and some of them were repeatedly registered at the same sector in the area, suggesting that although they occupy an extensive area, they use it in an intended way. When compared to researches that used photographs to identify cetaceans, the video images showed some loss of information, nevertheless the analysis could be done without impairment of results, therefore this method proved to be efficient.

Habitat use by marine tucuxis (Sotalia guianensis) (Cetacea: Delphinidae) in Guanabara Bay, south-eastern Brazil

2007 ◽  
Vol 87 (1) ◽  
pp. 201-205 ◽  
Author(s):  
Alexandre F. Azevedo ◽  
Alvaro M. Oliveira ◽  
Simone C. Viana ◽  
Monique Van Sluys
Keyword(s):  
Habitat Use ◽  
Habitat Degradation ◽  
Guanabara Bay ◽  
Sotalia Guianensis ◽  
South Eastern ◽  
The North ◽  
Eastern Brazil ◽  
North Eastern ◽  
Kolmogorov Smirnov ◽  
South Axis

Data on habitat use by marine tucuxis (Sotalia guianensis) were collected in Guanabara Bay (GB), south-eastern Brazil, over a two-year period. Diurnal activities of marine tucuxis were dominated by behaviour related to feeding/foraging (58% of all recorded time). Dolphins spent more time in feeding/foraging activities in the morning with a secondary peak in late afternoon. Dolphins were seen in waters of 2 to 35 m (11.63±6.05; median=12.0). Depths used by S. guianensis groups significantly differed from depths available in GB (Kolmogorov–Smirnov test; Z=5.72; P<0.001). Most groups (69.8%) were sighted in depths between 5.1 and 15.0 m. Dolphins occupied an area of 136.9 km2, which represents about 42% of the entire water surface of GB. Individuals selected areas within GB and avoided the most degraded ones, which suggests that habitat degradation may affect S. guianensis distribution. Diurnal distances travelled by individuals ranged from 3.3 to 27.2 km in a same day. Dolphins found in main channel and adjacent waters moved along the north–south axis of GB throughout the day and covered distances three times greater than dolphins which concentrated their activities in north-eastern areas.

Stomach contents of the marine tucuxi dolphin (Sotalia guianensis) from Rio de Janeiro, south-eastern Brazil

2007 ◽  
Vol 87 (1) ◽  
pp. 253-254 ◽  
Author(s):  
Ana Paula Madeira Di Beneditto ◽  
Salvatore Siciliano
Keyword(s):  
Rio De Janeiro ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Additional Information ◽  
Sotalia Guianensis ◽  
South Eastern ◽  
Eastern Brazil ◽  
Trichiurus Lepturus ◽  
Cynoscion Guatucupa ◽  
Janeiro State

Along the central coast of Rio de Janeiro State (22°25′S–23°00′S), south-eastern Brazil, the marine tucuxi dolphin (Sotalia guianensis) feeds on neritic prey that are distributed through the water column and are abundant all year round. The most frequently found species were the teleost fish Trichiurus lepturus, Cynoscion guatucupa, Isopisthus parvipinnis and Porichthys porossisimus. Fish species were more important than cephalopod species in the diet of the marine tucuxi. Back calculations of prey sizes indicated that they feed mainly on young specimens. The present study provided additional information on the feeding habits of the marine tucuxi dolphin.

Occurrence and habitat use of Bryde's whales (Balaenoptera edeni) in the Cabo Frio region, South-eastern Brazil

2016 ◽  
Vol 98 (5) ◽  
pp. 1081-1086 ◽  
Author(s):  
Israel S. Maciel ◽  
Rodrigo H. Tardin ◽  
Sheila M. Simão
Keyword(s):  
Habitat Use ◽  
Foraging Behaviour ◽  
Field Trips ◽  
South Eastern ◽  
Video Recordings ◽  
Eastern Brazil ◽  
Water Depths ◽  
Cabo Frio

Ninety-six field trips were conducted between summer 2010 and 2012 in order to understand the occurrence and habitat use of Bryde's whale (Balaenoptera edeni) in the Cabo Frio region, South-eastern Brazil. Bryde's whales were present in the study area between November and July, being observed during all seasons, but occur more frequently during the autumn (Nindividuals = 16) and spring (Nindividuals = 13), followed by summer (Nindividuals = 5) and winter (Nindividuals = 2), respectively. Bryde's whales were observed in water depths ranging from 20.1–100 m. Furthermore, during 2240 min of video recordings, the most frequent behaviour observed was foraging (40.2%; 900 min). Travelling comprised 28.1% (630 min) of observations, while in 33.1% (710 min) behaviour could not be determined. Taking into account the pattern of occurrence, the use of deeper bathymetric bins and the frequency observed, the foraging behaviour of Bryde's whales observed in our study seems to be associated to prey dynamics. Our data show that the study area is frequently used for foraging by this species in Brazilian waters.

Degrees of residence of Guiana dolphins (Sotalia guianensis) in Ilha Grande Bay, south-eastern Brazil: a preliminary assessment

2010 ◽  
Vol 90 (8) ◽  
pp. 1633-1639 ◽  
Author(s):  
Mariana de A. Espécie ◽  
Rodrigo H.O. Tardin ◽  
Sheila M. Simão
Keyword(s):  
Resource Availability ◽  
Southern Brazil ◽  
Preliminary Assessment ◽  
Photo Identification ◽  
Sotalia Guianensis ◽  
South Eastern ◽  
Eastern Brazil ◽  
Low Degree ◽  
Identification Technique ◽  
Over Time

The Guiana dolphin, Sotalia guianensis, is a small delphinid found in coastal areas from northern Honduras to southern Brazil. Little is known about the ecology of this species in several areas of its geographical distribution. In this paper, we present new data about the residency of Guiana dolphins in Ilha Grande Bay, south-eastern Brazil. Boat surveys were conducted at the study area from May 2007 to March 2008. Applying the photo-identification technique, we took pictures of dolphins' dorsal fins, looking for natural markings on them. A total of 17,969 photographs were taken, from which was created a databank of 462 distinct dolphins. Individuals showed different degrees of residency in the bay. More than 50% of the catalogued dolphins were considered non-residents and/or showed a low degree of residence. The average interval between resightings was 35 ± 27.4 days. Animals without markings (calves and juveniles) accounted for 45% (N = 2917) of photographs taken. These results indicate that this population has a fluid structure including different individuals over time. We suggest a possible relationship between the presence of some individuals and local resource availability, such as prey and protected areas.

Aggregations of Guiana dolphins (Sotalia guianensis) in Sepetiba Bay, Rio de Janeiro, south-eastern Brazil: distribution patterns and ecological characteristics

2009 ◽  
Vol 89 (5) ◽  
pp. 967-973 ◽  
Author(s):  
Laura Aichinger Dias ◽  
Denize Herzing ◽  
Leonardo Flach
Keyword(s):  
Temporal Distribution ◽  
Distribution Patterns ◽  
Conservation Strategies ◽  
Temporal Association ◽  
Sepetiba Bay ◽  
Sotalia Guianensis ◽  
Behavioural Activity ◽  
Eastern Brazil ◽  
Feeding Activities ◽  
Guiana Dolphin

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 behaviour but not necessarily moving in the same direction. Guiana dolphin groups and aggregations differed significantly in behavioural 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 GPS records of aggregations formed two distinct clusters of distribution within the bay, indicating potential areas where conservation strategies could be implemented.

scholarly journals Feeding habits of Guiana dolphins, Sotalia guianensis, from south-eastern Brazil: new items and a knowledge review

2012 ◽  
Vol 92 (8) ◽  
pp. 1723-1733 ◽  
Author(s):  
Xênia Moreira Lopes ◽  
Ednilson da Silva ◽  
Manuela Bassoi ◽  
Roberta Aguiar dos Santos ◽  
Marcos César de Oliveira Santos
Keyword(s):  
Fish Species ◽  
Coastal Waters ◽  
Feeding Habits ◽  
Regression Equations ◽  
Estuarine Waters ◽  
Sotalia Guianensis ◽  
South Eastern ◽  
Cephalopod Species ◽  
Eastern Brazil ◽  
Important Fish

This study presents new information on feeding habits of Guiana dolphins, Sotalia guianensis, in south-eastern Brazil, together with new regression equations to evaluate the weight and length of fish from otoliths, showing an overview on the knowledge about this species’ diet in this area. Eighteen stomach contents had been analysed and compared to 180 samples collected in another eight feeding studies. The analysed specimens were either incidentally caught in gillnets used in coastal waters by the fleet based in the Cananéia main harbour (25°00′S 47°55′W), south of São Paulo State, or found dead in inner waters of the Cananéia estuary between 2003 and 2009. Based on the index of relative importance analysis, the most important fish species were the banded croaker, Paralonchurus brasiliensis. Doryteuthis plei was the most representative cephalopod species. Stellifer rastrifer was the most important fish species observed in dolphins in inner estuarine waters and P. brasiliensis in recovered dolphins from coastal waters. Loliguncula brevis is the only cephalopod species reported from dolphins found in inner estuarine waters up to date. Doryteuthis plei was the most important cephalopod species observed in coastal dolphins. When considering other feeding studies, the most representative fish family in the diet of S. guianensis was Sciaenidae, which is mainly represented by demersal fishes. The main preys of S. guianensis are abundant in the studied areas, which may indicate an opportunistic feeding habit. The majority of them are not the most important target species by the commercial fishery in south-eastern Brazil.

Trophic ecology and foraging areas of cetaceans sampled in the coastal waters of south-eastern Brazil assessed through skin δ13C and δ15N

2021 ◽  
pp. 1-10
Author(s):  
Victor Uber Paschoalini ◽  
Genyffer Cibele Troina ◽  
Laura Busin Campos ◽  
Marcos César de Oliveira Santos
Keyword(s):  
Habitat Use ◽  
Coastal Waters ◽  
Trophic Ecology ◽  
Trophic Position ◽  
Trophic Levels ◽  
Eastern Coast ◽  
Cetacean Species ◽  
Δ13c And Δ15n ◽  
South Eastern ◽  
Eastern Brazil

Abstract We investigated the habitat use and feeding ecology of 10 cetacean species encountered along the south-eastern coast of Brazil (24–26°S) using carbon (δ13C) and nitrogen (δ15N) stable isotopes. Hierarchical cluster analysis distinguished two main groups based on their isotopic patterns. One group included migratory baleen whales (Megaptera novaeangliae and Eubalaena australis) with the lowest δ13C and δ15N values, reflecting baseline isotopic values of their Subantarctic feeding grounds and consumption of lower trophic level prey. Resident species and those occasionally occurring in Brazilian coastal waters highly differed from the migratory whales in their isotopic values. In this group, Tursiops truncatus had the highest δ13C and δ15N values, indicating coastal habits and relatively higher trophic position. Similar δ13C values were observed in Sotalia guianensis, Pontoporia blainvillei, Orcinus orca and Steno bredanensis. However, the former two species had lower δ15N values than the latter two, indicating different trophic positions. The relatively lower δ13C values observed in Stenella frontalis suggest greater influence of pelagic prey in their diet. Furthermore, the lower δ13C values observed in Delphinus delphis and Balaenoptera edeni were associated with upwelling events that occur along the region, affecting the isotopic values of their main prey. Juvenile M. novaeangliae had higher δ13C and δ15N than the adults, which may indicate feeding in areas with different isoscapes and consumption of pelagic schooling fish with relatively higher trophic levels than krill. This study provides preliminary information that are useful to understand the habitat use and coexistence of cetacean species occurring in south-eastern Brazil.

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