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.

Clinical signs in free-ranging Guiana dolphins Sotalia guianensis during a morbillivirus epidemic: case study in Sepetiba Bay, Brazil

2019 ◽  
Vol 133 (3) ◽  
pp. 175-180 ◽  
Author(s):  
L Flach ◽  
MB Alonso ◽  
T Marinho ◽  
K Van Waerebeek ◽  
MF Van Bressem
Keyword(s):  
Clinical Signs ◽  
Sepetiba Bay ◽  
Sotalia Guianensis ◽  
Free Ranging

Rostrum Contact Behaviors by the Guiana Dolphin (Sotalia guianensis) in Ilhéus, Brazil

2016 ◽  
Vol 42 (2) ◽  
pp. 203-209
Author(s):  
Flavia B. Izidoro ◽  
Yvonnick Le Pendu
Keyword(s):  
Sotalia Guianensis ◽  
Guiana Dolphin

scholarly journals Intra-Storm Pattern Recognition through Fuzzy Clustering

Hydrology ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 57
Author(s):  
Konstantinos Vantas ◽  
Epaminondas Sidiropoulos
Keyword(s):  
Fuzzy Clustering ◽  
A Priori ◽  
Temporal Distribution ◽  
Distribution Patterns ◽  
Rainfall Data ◽  
Rainfall Runoff ◽  
Domain Specific ◽  
Runoff Modeling ◽  
National Bank ◽  
Rainfall Patterns

The identification and recognition of temporal rainfall patterns is important and useful not only for climatological studies, but mainly for supporting rainfall–runoff modeling and water resources management. Clustering techniques applied to rainfall data provide meaningful ways for producing concise and inclusive pattern classifications. In this paper, a timeseries of rainfall data coming from the Greek National Bank of Hydrological and Meteorological Information are delineated to independent rainstorms and subjected to cluster analysis, in order to identify and extract representative patterns. The computational process is a custom-developed, domain-specific algorithm that produces temporal rainfall patterns using common characteristics from the data via fuzzy clustering in which (a) every storm may belong to more than one cluster, allowing for some equivocation in the data, (b) the number of the clusters is not assumed known a priori but is determined solely from the data and, finally, (c) intra-storm and seasonal temporal distribution patterns are produced. Traditional classification methods include prior empirical knowledge, while the proposed method is fully unsupervised, not presupposing any external elements and giving results superior to the former.

Population biology and diet of the puffer fish Lagocephalus laevigatus (Tetraodontiformes: Tetraodontidae) in Caraguatatuba Bay, south-eastern Brazil

2011 ◽  
Vol 92 (2) ◽  
pp. 407-412 ◽  
Author(s):  
M.R. Denadai ◽  
F.B. Santos ◽  
E. Bessa ◽  
L.P. Bernardes ◽  
A. Turra
Keyword(s):  
Population Biology ◽  
Temporal Distribution ◽  
Late Winter ◽  
Entire Study Period ◽  
Entire Study ◽  
South Eastern ◽  
Eastern Brazil ◽  
Puffer Fish ◽  
Spatio Temporal ◽  
Sexually Mature

This study describes the spatio-temporal distribution, population biology, and diet of the puffer fish Lagocephalus laevigatus in Caraguatatuba Bay, south-eastern Brazil. Monthly samples were taken between August 2003 and October 2004 by trawls in two areas, south and north, at depths of 1 to 4 m. The fish were measured and their sex and reproductive stage determined. The abundance of this species was compared between areas and among months, and the items in the diet were identified and quantified. Lagocephalus laevigatus was rare in Caraguatatuba Bay, where only 199 small individuals (4.8 to 15.4 cm) were obtained in the entire study period, suggesting that this species uses the estuary as a nursery. None of the specimens of L. laevigatus captured in Caraguatatuba Bay were sexually mature. Higher densities of L. laevigatus in the bay were recorded in the south area and between October and December 2003, i.e. in the spring, suggesting that spawning may occur from late winter to spring (August through to November). The diet items consumed by L. laevigatus in Caraguatatuba Bay were, as expected from the current literature, crustaceans, mainly amphipods, and fish. However, the most-consumed item was the sea whip Leptogorgia setacea (Cnidaria). This feeding habit may be related to the presence of toxins (tetrodotoxin and saxitoxin) that are frequently found in the skin and viscera of L. laevigatus, which may be sequestered from the sea whip, which possibility still needs to be specifically evaluated.

scholarly journals Temporal and Spatial Coexistence of Archaeal and BacterialamoAGenes and Gene Transcripts in Lake Lucerne

Archaea ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Elisabeth W. Vissers ◽  
Flavio S. Anselmetti ◽  
Paul L. E. Bodelier ◽  
Gerard Muyzer ◽  
Christa Schleper ◽  
...  
Keyword(s):  
Temporal Distribution ◽  
Water Layer ◽  
Distribution Patterns ◽  
Freshwater Ecosystems ◽  
Ammonia Oxidizers ◽  
Lake Lucerne ◽  
Ammonia Oxidizing Archaea ◽  
Gene Transcripts ◽  
Temporal And Spatial

Despite their crucial role in the nitrogen cycle, freshwater ecosystems are relatively rarely studied for active ammonia oxidizers (AO). This study of Lake Lucerne determined the abundance of bothamoAgenes and gene transcripts of ammonia-oxidizing archaea (AOA) and bacteria (AOB) over a period of 16 months, shedding more light on the role of both AO in a deep, alpine lake environment. At the surface, at 42 m water depth, and in the water layer immediately above the sediment, AOA generally outnumbered AOB. However, in the surface water during summer stratification, when both AO were low in abundance, AOB were more numerous than AOA. Temporal distribution patterns of AOA and AOB were comparable. Higher abundances ofamoAgene transcripts were observed at the onset and end of summer stratification. In summer, archaealamoAgenes and transcripts correlated negatively with temperature and conductivity. Concentrations of ammonium and oxygen did not vary enough to explain theamoAgene and transcript dynamics. The observed herbivorous zooplankton may have caused a hidden flux of mineralized ammonium and a change in abundance of genes and transcripts. At the surface, AO might have been repressed during summer stratification due to nutrient limitation caused by active phytoplankton.

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.

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