scholarly journals Use of otolith strontium : calcium ratio as an indicator of seasonal displacements of the silverside (Odontesthes bonariensis) in a freshwater–marine environment

2013 ◽  
Vol 64 (8) ◽  
pp. 746 ◽  
Author(s):  
E. Avigliano ◽  
A. V. Volpedo
Keyword(s):  
Marine Environment ◽  
Calibration Curve ◽  
Paraná River ◽  
River Delta ◽  
Water Bodies ◽  
Rio De La Plata ◽  
Río De La Plata ◽  
La Plata ◽  
Parana River ◽  
Odontesthes Bonariensis

Strontium : calcium (Sr : Ca) ratios were measured in sagittal otoliths of silverside (Odontesthes bonariensis) from a freshwater–marine environment (Paraná River Delta and Río de la Plata River, South America) in order to understand its seasonal movements. Conductivity was recorded and the water Sr : Ca ratio was determined by inductively coupled plasma–atomic emission spectrometry (ICP-OES). A calibration curve of water Sr : Ca ratio versus otolith Sr : Ca ratio from four isolated lentic water bodies was made to predict silverside displacements in the lower section of the Plata Basin during summer (lotic water bodies). Otolith Sr : Ca ratio of silversides from the Paraná River Delta was associated with the conductivity of water at the locations where the sample was collected. According to this association and the obtained results in the calibration curve, the silversides were displaced from zones where conductivity was 7.45 (mS cm–1), corresponding to the water Sr : Ca ratio in the outer section of the Río de la Plata River (1.92 mmol mol–1). The high values of otolith Sr : Ca ratio found for some fish may indicate that during summer they moved from estuarine waters where salinity increases gradually to the Argentinian Sea.

Geographic distribution of the short-tailed river stingray (Potamotrygon brachyura): assessing habitat loss and fishing as threats to the world’s largest obligate freshwater elasmobranch

2016 ◽  
Vol 67 (10) ◽  
pp. 1463 ◽  
Author(s):  
Luis O. Lucifora ◽  
Santiago A. Barbini ◽  
Sabina Llamazares Vegh ◽  
Pablo A. Scarabotti ◽  
Facundo Vargas ◽  
...  
Keyword(s):  
Water Temperature ◽  
Geographic Distribution ◽  
River Basins ◽  
Paraná River ◽  
Habitat Modification ◽  
Rio De La Plata ◽  
Fishing Pressure ◽  
Río De La Plata ◽  
La Plata ◽  
Parana River

Freshwater elasmobranchs are threatened but little is known about them. Potamotrygon brachyura is the world’s largest obligate freshwater elasmobranch. This makes it popular among fishermen and suggests a susceptibility to anthropogenic threats. We collected records of P. brachyura (n=70) from media, fishermen and scientific sampling, to estimate its global geographic distribution (using both generalised additive and MaxLike models). Then, we estimated the species’ exposure to habitat modification and fishing pressure, by applying multinomial ordinal models with threat levels as response and the presence or absence of P. brachyura as an independent variable. Distance to coast, depth, water temperature range, salinity range and mean water temperature were the main determinants of the distribution in the Río de la Plata. This resulted in a narrow coastal distribution. In the Uruguay and Paraná River basins, the probability of occurrence was positively associated with flow accumulation, percentage of open water and submerged vegetation, and lowland ecoregions, and negatively to wetness index and altitude. This limited the distribution to large lowland rivers. Approximately 41% of the range of P. brachyura in the Río de la Plata was subject to high habitat modification. In the Uruguay and Paraná River basins, this percentage reached 7%; however, the overlap with high fishing pressure was 59%. For conservation purposes, P. brachyura may function as an umbrella species.

Heavy metal concentrations in the Lower Paraná River and right margin of the Río de la Plata Estuary

1998 ◽  
Vol 26 (3) ◽  
pp. 963-966
Author(s):  
C. Villar ◽  
M. Tudino ◽  
C. Bonetto ◽  
L. de Cabo ◽  
J. Stripeikis ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Paraná River ◽  
Rio De La Plata ◽  
Río De La Plata ◽  
Metal Concentrations ◽  
Heavy Metal Concentrations ◽  
La Plata ◽  
Parana River

scholarly journals Stranded humpback whale (Megaptera novaeangliae) (Cetacea: Balaenopteridae) in Paraná River Delta, Buenos Aires Province, Argentina. Comments on the occurrence of marine mammals in the La Plata River Basin

2018 ◽  
Vol 58 ◽  
pp. 1 ◽  
Author(s):  
Sergio O. Lucero ◽  
María Constanza Gariboldi ◽  
Valeria Bauni ◽  
Juan Manuel Meluso ◽  
Daniela Del Castillo ◽  
...  
Keyword(s):  
River Basin ◽  
Marine Mammals ◽  
Buenos Aires ◽  
Humpback Whale ◽  
Paraná River ◽  
Megaptera Novaeangliae ◽  
River Delta ◽  
Buenos Aires Province ◽  
La Plata ◽  
Parana River

The humpback whale (Megaptera novaeangliae) is distributed among most oceans and seas of the globe (except Mediterranean Sea). These whales migrate from feeding regions in the Antarctic waters to breeding areas in tropical and subtropical seas. Here we report the stranding of a female young humpback whale, which was founded dead in the vicinity of the Talavera Island, in the Paraná River Delta, Buenos Aires Province, Argentina. From the analysis of mitochondrial cytochrome c oxidase subunit I gene sequences, two novel haplotypes were found, totalizing four haplotypes described for the species. In the La Plata River Basin this species was found only twice at the end of the XIX century. Thus, the new finding constitutes an important addition to the list of cetaceans that occurs in Uruguay, Paraná and La Plata Rivers.

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