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

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.

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

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315407053647 ◽

2007 ◽

Vol 87 (1) ◽

pp. 253-254 ◽

Cited By ~ 29

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.

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The sharksucker ( Echeneis naucrates) attached to a tucuxi dolphin ( Sotalia guianensis) in estuarine waters in south-eastern Brazil

Marine Biodiversity Records ◽

10.1017/s1755267205000746 ◽

2008 ◽

Vol 1 ◽

Author(s):

Marcos César de Oliveira Santos ◽

Ivan Sazima

Keyword(s):

Estuarine Waters ◽

Sotalia Guianensis ◽

South Eastern ◽

Eastern Brazil

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Insights on site fidelity and calving intervals of the marine tucuxi dolphin (Sotalia fluviatilis) in south-eastern Brazil

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315401005045 ◽

2001 ◽

Vol 81 (6) ◽

pp. 1049-1052 ◽

Cited By ~ 32

Author(s):

Marcos César de Oliveira Santos ◽

Luciana Barão Acuña ◽

Sergio Rosso

Keyword(s):

Small Area ◽

Site Fidelity ◽

Photo Identification ◽

South Eastern ◽

Eastern Brazil ◽

Ecological Aspects ◽

Sotalia Fluviatilis ◽

Calving Intervals ◽

Long Term Studies

Ecological aspects of the marine tucuxi dolphin, Sotalia fluviatilis (Cetacea: Delphinidae), remain poorly known. Important information can be gathered in long-term studies using photo-identification. Using this methodology, the authors present the first evidence of site fidelity for marine tucuxis in the Cananéia Estuary (25°03′S 48°01′ W), south-eastern Brazil. A total of 86 easily recognizable individuals was catalogued from June 1996 to August 2001, but most of them have been sighted from May 2000. From June 1997 to August 2001, three female tucuxis were sighted on nine (KN #19), 22 (KN #30) and 28 (KN #10) different days in a relatively small area (∼16 km2). Each of them was observed with a calf in 1997–1998 and again with a new offspring in 2000–2001. Thirteen other individuals were reported on eight to 19 different days in the same area between May 2000 and August 2001. Our observations lead to conclusions on the evidence of site fidelity and indicate that calving intervals may range between two and three years for this species in the surveyed area.

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Studies on mosquitoes (Diptera: Culicidae) and anthropic environment: 4 - Survey of resting adults and synanthropic behaviour in South-Eastern, Brazil

Revista de Saúde Pública ◽

10.1590/s0034-89101993000600002 ◽

1993 ◽

Vol 27 (6) ◽

pp. 398-411 ◽

Cited By ~ 40

Author(s):

Oswaldo Paulo Forattini ◽

Iná Kakitani ◽

Eduardo Massad ◽

Daniel Marucci

Keyword(s):

The Other ◽

Population Increase ◽

Human Settlements ◽

Human Environment ◽

South Eastern ◽

Other Hand ◽

Eastern Brazil ◽

Low Degree ◽

Consequent Increase

Resting adults Culicidae were collected from January 1992 through January 1993 in several habitats of the Ribeira Valley region. The diversity of species found among them suggested that the vegetation remaining within human settlements favored the survival and the population increase of some mosquitoes. Among there are: Ae. scapularis, Ae. serratus, Cx. (Culex), Cx. nigripalpus and Cx. (Melanoconion) such as Cx. ribeirensis. That preservation role may be attributed to the rearing of livestock and the consequent increase in the number of blood sources. These species may be classified as hemisynanthropes and Cx. oedipus apparently evolving to the eusynanthropic status. On the other hand, An. cruzii showed an asynanthropic behaviour, with a low degree of survival in the modified human environment. Epidemiological implications of the data are mentioned.

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

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315412000495 ◽

2012 ◽

Vol 92 (8) ◽

pp. 1723-1733 ◽

Cited By ~ 13

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.

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

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315408000398 ◽

2008 ◽

Vol 88 (6) ◽

pp. 1199-1205 ◽

Cited By ~ 3

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.

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