SOTALIA GUIANENSIS POPULATION DENSITY ESTIMATIVE IN THE BAY OF ANTONINA, BRAZIL

The present work aimed to estimate the population density of Sotalia guianensis in the Bay of Antonina, southern Brazilian coast, by linear transects, distance method. The average group size in the total area was 2.57 individuals/group. The study area is 28.1 km2 and it was divided in two sub-areas, an outer area closer to the sea and another more enclosed with a higher fresh water input. In the Sector I, the one with greater marine influence, the density estimation found was D = 3.01 animals/ km2 (Variation Coefficient, VC 24.67%), whereas in Sector II there was no estuarine dolphin record. Also, during the rainy season a higher density value was found in the bay (D = 4.99 individuals/ km2, VC 15.93%). When the area division was ignored an overestimation of density was found (D = 3.80 animals/km2; VC 15.71%) due to the data extrapolation beyond the sampled area, including areas not much used by the dolphins. This superestimation due to the few estuarine dolphins records in the Bay of Antonina and also to the method used, which was biased by existing of sand banks at low tide which made it impossible to access all transects.

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Behavioral patterns and movement intensity of Sotalia guianensis (P. J. van Bénéden) (Cetacea, Delphinidae) in two different areas on the Brazilian coast

Revista Brasileira de Zoologia ◽

10.1590/s0101-81752007000200001 ◽

2007 ◽

Vol 24 (2) ◽

pp. 265-270 ◽

Cited By ~ 9

Author(s):

Fábio G. Daura-Jorge ◽

Marcos R. Rossi-Santos ◽

Leonardo L. Wedekin ◽

Paulo C. Simões-Lopes

Keyword(s):

Behavioral Pattern ◽

Eastern Coast ◽

Brazilian Coast ◽

Behavioral Patterns ◽

Southern Coast ◽

Sotalia Guianensis ◽

Pattern Frequency ◽

Movement Intensity ◽

Estuarine Dolphin ◽

Two Populations

The behavioral patterns of the estuarine dolphin, Sotalia guianensis (P. J. van Bénéden, 1864), were compared between two populations along the Brazilian coast: Caravelas (Bahia), along the eastern coast, and Norte Bay (Santa Catarina), along the southern coast. Applying the focal-group sampling in both areas, information such as the geographic position (UTM) of groups and predominant behavioral patterns were obtained. Geographic positions were used to calculate the total distance traveled by estuarine dolphin groups on each observation day. Since the distance traveled varies with time, the daily mean speed of the dolphin’s group was used as an index of movement intensity. Two comparable and easily recognizable behavioral patterns were considered: travelling and foraging. Overall movement intensity and behavioral pattern frequency were similar between both areas. However, a seasonal variation was observed in both parameters in Norte Bay, while in Caravelas these parameters were homogeneous throughout the year. Variation in the behavior of the estuarine dolphin was consistent with variations in environmental factors, such as water temperature.

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Spatial distribution and activities of the estuarine dolphin Sotalia guianensis (van Bénédén, 1864) (Cetacea, Delphinidae) in Pontal Bay, Ilhéus, Bahia, Brazil

Biota Neotropica ◽

10.1590/s1676-06032010000200007 ◽

2010 ◽

Vol 10 (2) ◽

pp. 67-73 ◽

Cited By ~ 4

Author(s):

Urânia Amaral dos Santos ◽

Martin Roberto Alvarez ◽

Ana Cristina Schilling ◽

Gil Marcelo Reuss Strenzel ◽

Yvonnick Le Pendu

Keyword(s):

Spatial Distribution ◽

Water Depth ◽

High Tide ◽

Temporal Distribution ◽

Sotalia Guianensis ◽

Direct Observations ◽

Average Group ◽

Spatio Temporal ◽

Estuarine Dolphin ◽

Average Group Size

We analyzed the influence of time, tide and water depth on the activity and spatial distribution of estuarine dolphins Sotalia guianensis in Pontal Bay, Ilhéus, Brazil. Direct observations were carried out at four fixed points from January to December of 2006. Estuarine dolphins were sighted in 11 out of 12 months and in 30% of 181 sampling periods. The average group size, which was 3.75 ± 1.59 (n = 64), did not vary significantly by month (Kruskal-Wallis, H = 10.6729; p = 0.3836). Infants and adults represented 18 and 82% of the individuals whose age we were able to determine, respectively. Estuarine dolphins were more frequently present than expected in areas deeper than 3 m (regression GLM, z = 3.773; p = 0.0002). The animals were more frequently observed between 7:00 and 8:00 AM and between 3:00 and 5:00 PM (X² = 83.815; p < 0.0001). Their presence in the bay tripled between the fourth hour of the flood and high tide, remaining elevated during the ebb tide (X² = 22.152; p = 0.02). The tide also influenced the animals' feeding and travelling direction, mainly toward the open see during the flood and to the back of the bay during others stages. Further studies are necessary to analyze the influence of the hydrographic characteristics of Pontal Bay on the spatio-temporal distribution of estuarine dolphins and their prey.

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Behavioural seasonality of the estuarine dolphin, Sotalia guianensis, on the north-eastern Brazilian coast

Marine Biodiversity Records ◽

10.1017/s1755267207006628 ◽

2008 ◽

Vol 1 ◽

Author(s):

Fernando Roberto Guilherme-Silveira ◽

Flávio José de Lima Silva

Keyword(s):

Brazilian Coast ◽

Sotalia Guianensis ◽

The North ◽

North Eastern ◽

Estuarine Dolphin

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The occurrence of Pontoporia blainvillei (Gervais & d'Orbigny) (Cetacea, Pontoporiidae) in an estuarine area in southern Brazil

Revista Brasileira de Zoologia ◽

10.1590/s0101-81752005000300032 ◽

2005 ◽

Vol 22 (3) ◽

pp. 717-723 ◽

Cited By ~ 15

Author(s):

Marta J. Cremer ◽

Paulo C. Simões-Lopes

Keyword(s):

Great Difficulty ◽

Northern Coast ◽

Southern Brazil ◽

Average Group ◽

Southwestern Atlantic Ocean ◽

Estuarine Dolphin ◽

Pontoporia Blainvillei ◽

And Behavior ◽

Average Group Size ◽

Phalacrocorax Brasilianus

The toninha, or franciscana, Pontoporia blainvillei (Gervais & D'Orbigny, 1844), is an endemic species of cetacean of the southwestern Atlantic Ocean. There is little information on the occurrence of this species in its natural environment due to the great difficulty in sighting it. Systematized and non-systematized observations of franciscanas were made from December 1996 through November 2001 at Babitonga Bay, on the northern coast of Santa Catarina State, southern Brazil. The observations were made from small motorboats. A total of 79 observations were made, totaling 561 individuals. Up to 59.5% of the groups consisted of over four individuals and the average group size was seven. Calves were present in 30.4% of the observations. The species was found throughout the year within the bay and preferential areas were identified. Calves were registered during all seasons. Data are presented on the behavior (feeding, traveling, aerial behavior and behavior relating to the boats) and on inter-specific interactions with terns, cormorants [Phalacrocorax brasilianus (Gmelin, 1789)] and brown boobies [Sula leucogaster (Boddaert, 1783)]. The species is sympatric with the estuarine dolphin Sotalia guianensis (P. J. Van Bénéden, 1864) in the bay, but there was no record of interaction between them. The area of the bay represents an important refuge for the franciscana species.

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The estimation of neuronal population density by a robust distance method

Journal of Microscopy ◽

10.1111/j.1365-2818.1978.tb00138.x ◽

1978 ◽

Vol 114 (3) ◽

pp. 285-293 ◽

Cited By ~ 25

Author(s):

W. A. Aherne ◽

P. J. Diggle

Keyword(s):

Population Density ◽

Neuronal Population ◽

Distance Method

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Radionuclides as tracers of coastal processes in Brazil: review, synthesis, and perspectives

Brazilian Journal of Oceanography ◽

10.1590/s1679-87592008000200004 ◽

2008 ◽

Vol 56 (2) ◽

pp. 115-130 ◽

Cited By ~ 26

Author(s):

Isaac R. Santos ◽

William C. Burnett ◽

José M. Godoy

Keyword(s):

Coastal Lagoons ◽

Phosphate Fertilizer ◽

Depositional Environments ◽

Brazilian Coast ◽

Petroleum Processing ◽

Artificial Radionuclide ◽

Economic Activities ◽

Radium Isotopes ◽

Erosion Processes ◽

The One

We review the usefulness, limitations, significance, and coastal management implications of radionuclide measurements in Brazilian coastal environments. We focus on the use of radionuclides as tracers of sedimentary processes and submarine groundwater discharge (SGD). We also discuss artificial radionuclide contamination and high natural radioactivity areas. The interpretation of 14C-, 137Cs-, and 210Pb-derived sedimentation rates has provided evidence that inappropriate soil use by urban and agricultural activities has intensified erosion processes on land, which is reflected in depositional environments, such as coastal lagoons, estuaries and mangroves. Of the processes discussed in this paper, SGD is the one that requires the most scientific effort in the short-term. There have been only two case studies using 222Rn and radium isotopes as groundwater tracers in Brazil. These investigations showed that SGD can be a major source of nutrients and other dissolved species to the coastal ocean. Baseline 137Cs, 90Sr, 239+240Pu, and 238Pu concentrations in seawater from the whole Brazilian coastal zone are very low. Therefore, in spite of contamination problems in many ecosystems in the northern hemisphere, artificial radionuclide pollution appears to be negligible along the Brazilian coast. Phosphate fertilizer industries and petroleum processing facilities are the main economic activities producing Technologically Enhanced Naturally Occurring Radioactive Materials (TENORM). Even though a few attempts have been made to assess the radiological effects of these activities, their potential threats indicate a need for the radiological control of their wastes. This review showed that the number of studies within the field of environmental radioactivity is still small in Brazil and much more research is needed to understand processes of high interest for environmental managers. In the near future, it is likely that such studies in Brazil will move from descriptive, environmental quality-based assessments to approaches that attempt to quantify chemical, physical, and biological processes in the environment.

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Structure of benthic macroinvertebrates and dynamics in the northern lagoon of Tunis

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315409000721 ◽

2009 ◽

Vol 89 (7) ◽

pp. 1305-1318 ◽

Cited By ~ 3

Author(s):

S. Tlig-Zouari ◽

T. Mami ◽

F. Maamouri

Keyword(s):

Benthic Macroinvertebrates ◽

Benthic Community ◽

Benthic Communities ◽

Remarkable Change ◽

Abiotic Parameters ◽

Gulf Of Tunis ◽

Physico Chemical ◽

Marine Influence ◽

The One ◽

As Effects

Sampling data on abiotic parameters and benthic communities in the northern lagoon of Tunis were obtained seasonally from November 1999 to November 2000. Abiotic parameters studied revealed evident improvement of water quality compared with previous. Indeed, management has re-established a tidal marine influence (Gulf of Tunis), induced a remarkable change in physico-chemical parameters and as a consequence, a regulation of the lagoon environmental quality. A total of 90 species of benthic macroinvertebrates, belonging to seven different taxa were collected in the northern lagoon of Tunis. A comparison of ecological indices indicate significant variations in the spatial and seasonal distribution and structure of the benthic community and reflect changes that might be related to open marine water and climatic influences as well as effects of discharge of the neighbouring city. Generally, the lagoon macrobenthic community appeared to be better structured, richer and more diverse than the one described before sanitation works began. However, significant disturbance of the benthic communities is detected in the south-eastern lagoon zone (C) and is dominated by disturbance indicator species. In contrast, the Station A2 which is sufficiently influenced by marine currents, is dominated by species of marine affinity and indicates an undisturbed zone. Multivariate analysis indicates heterogeneity in the benthic community structure between stations and suggests that the most significant variations of abundance occur in the groups: Anthozoa, Placophora, Cephalopoda, Ascidia and Echinodermata. The results of correspondence analysis also testify to a gradational distribution of benthic species in relation to hydrological and edaphic (organic matter) factors.

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Evaluation of periotic–timpanic bone complex of Sotalia guianensis (Cetacea: Delphinidae) as tool in identification of geographic variations

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315413001689 ◽

2013 ◽

Vol 94 (6) ◽

pp. 1127-1132 ◽

Cited By ~ 2

Author(s):

Danilo Leal Arcoverde ◽

Renata Emin-Lima ◽

Alexandra Fernandes Costa ◽

Ana Paula Madeira Di Beneditto ◽

Salvatore Siciliano ◽

...

Keyword(s):

Multivariate Analysis ◽

Geographic Variation ◽

Molecular Data ◽

Effective Characteristics ◽

Brazilian Coast ◽

Morphometric Characteristics ◽

Geographic Variations ◽

Morphometric Measurements ◽

Operational Taxonomic Units ◽

Sotalia Guianensis

Morphometric characteristics of the periotic–timpanic bone complex in the middle ear of cetaceans, are effective characteristics in evaluating systematics. However, they have not been used for studies of geographic variation regarding dolphins of the genus Sotalia. This study aimed to compare the periotic–timpanic of Sotalia guianensis from four distinct locations, considered here as different operational taxonomic units, Amapá/Pará (AM/PA), Maranhão/Piauí (MA/PI), Ceará (CE), and Rio de Janeiro (RJ), using 21 morphometric measurements. Multivariate analysis showed significant distinction mainly between the units of northern (AM/PA and MA/PI) and south-eastern (RJ) Brazilian coast. The timpanic bone showed variation, reaching larger sizes in the Brazilian south coast unit, corroborating current molecular data on the geographic variation of S. guianensis.

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