Tributary of Rio Paraná, Argentina

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Argentina, Entre Ríos

The floodplain of the Paraná river constitutes a wetland where the landscape is the result of continuous geomorphological and river processes that had place in the past and continue today. Because of its strategic location, it offers refuge, feeding, reproduction and breeding areas to different fish species, and constitutes an important place for the wide variety of living organisms that live in these waters.

Pre-Delta National Park is located southwest of Entre Rios Province – Argentina, on the left bank of the Paraná river, where the Paraná river forks in hundreds of meandering arms. At its northwest limit we can find this tributary.

The climate of the region is temperate-hot and humid, with an average annual temperature of 19 ºC and 900 mm of annual precipitation. There is more precipitation in the warm season and it is much drier in the cool season, so the relief, the depth and the transparency of the water depend of the floods.

Submitted by
Pedro Mendanha Dias
Approved by
Heiko Blessin & Nathan K. Lujan
-32.1216125, -60.6345291
Geographical region
South America
Drainage Basin
Paraná basin
River catchment
Water body type
Water body name
La Azotea - La Jaula
Water body part
Flood plain
Water body course
Water body: tributary of
Tributary name

Videos above and below water

Water Chemistry

Water information

Water type
Fresh water
Water color
Water transparency
Concentration of sediments
Water temperature
Change from 15 ºC in the winter, in the summer season to almost 27 °C
Water flow/curent

Chemical parameters

Dissolved Oxygen

Substrate in nature

Stone form
Submerged terrestrial vegetation

Aquatic Biotope

Date of collecting
Collecting area
Water depth
Air temperature


Affected by human activity
Affected by human activity
Surrounding area

The flood plain of the Paraná river constitutes a wetland where the landscape is the result of continuous geomorphological and river processes that had place in the past and continue today.

Underwater landscape

Analyzing the underwater morphology of this area, near the margin, we found that the predominant soil textures are characterized, in general, by the predominance of the silt fraction, with more variable clay and sand (small to medium size grain) concentrations, this fact makes the water cloudy, with little visibility. In addition, the periodic flood pulses promote the entry of suspended solids. It’s also possible to find some fine gravel and roundish rocks. And near the margin the water is slightly tea-color, with a slow flow, and normally some driftwood and dried leaf litter can be found.


  • Palaemon argentinus


  • Chaunus arenarum
  • Elachistocleis bicolor
  • Leptodactylus chaquensis
  • Physalaemus albonotatus
  • Amphibian Scinax nasicus


  • Aphyocharax anisitsi
  • Apistogramma borellii
  • Apistogramma commbrae
  • Astyanax asuncionensis
  • Astyanax stenohalinus
  • Brycon orbygnianus
  • Callichthys callichthys
  • Corydoras hastatus
  • Corydoras paleatus
  • Farlowella hahni
  • Gymnogeophagus balzanii
  • Gymnogeophagus meridionalis
  • Hyphessobrycon anisitsi
  • Hyphessobrycon eques
  • Loricaria luciae
  • Moenkhausia dichroura
  • Otocinclus arnoldi
  • Otocinclus vestitus
  • Phalloceros caudimaculatus
  • Pyrrhulina australis
  • Rineloricaria lanceolata
  • Rineloricaria parva
  • Serrapinnus kriegi

Wetland plant:

  • Paspalum sp.
  • Echinochloa crusgalli
  • Polygonum sp.
  • Cyperus entrerrianus
  • Panicum sabulorum

Aquatic plant:

  • Echinodorus grandiflorus
  • Echinodorus uruguayensis
  • Eichhornia crassipes
  • Eichhornia azurea
  • Eleocharis sp.
  • Gymnocoronis spilanthoides
  • Hydrocotyle sp.
  • Juncus sp.
  • Lemna minor
  • Hydrocharis laevigata
  • Myriophyllum aquaticum
  • Pistia stratiotes
  • Sagittaria montevidensis
Threats to ecology

Even if the tributary La Azotea – La Jaula is inserted in a National Park, where riverside forests appear with exotic tree species as dominant, all this natural area is surrounded by zones that present an intense landscape modification, due to an excessive agricultural and livestock activities, that origin a low environmental quality.

Plus, the industrial activity developed in areas close to the water courses, and the proximity to urban centers, generates a negative impact, mainly due to the spill of waste and sewages, which affect water quality and the diversity of this region wetlands, because they constitute a source of eutrophication and degradation of the environment, as it should not be forgotten that the biotope area is flooded, seasonally, every year.

Lastly, it is necessary to control the problems associated with the invasion of exotic trees like Fraxinus sp., Gleditsia tiracantos, Ligustrum lucidum, and Morus alba.

Riparian zone

Trees near the aquatic habitat
Few -


  • → Guía de los Peces del Parque Nacional Pre-Delta by ALMIRÓN, Adriana; CASCIOTTA Jorge; CIOTEK, Liliana; GIORGIS, Pablo
    ISBN 978-987-1363-23-0
  • Biodiversidad del Parque Nacional Pre-Delta by ACEÑOLAZA, Pablo al.
  • Características fisicoquímicas y bacteriológicas de los ambientes acuáticos del PNPD posteriores a un período de aguas altas by MIRANDE, Virginia et al.
  • Evaluación abiótica y biótica de ambientes acuáticos de un parque nacional entrerriano by MIRANDE, Virginia et al.
  • Las comunidades vegetales del Delta del Río Panrana. Su relación com factores ambientales y patrones del paisaje by MALVÁREZ, Ana Inés
  • → Bleher’s Biotopes by BLEHER, Heiko
  • Sistemas de paisajes de humedales del Corredor Fluvial Paraná-Paraguay by BENZAQUÉN, Laura et al.
  • Peces Pampeanos guía y ecología by ROSSO, Juan José
  • Peces y Ambientes en la Argentina continental by MENNI, R. C.
  • Catalogo de la flora vascular del PN Pre Delta by RODRIGUEZ, Estela Elizabeth; ACEÑOLAZA, Pablo; MUÑOZ, Juan de Dios

Comment by the expert

Heiko Blessin: Video doesn’t give a lot of information. Parameters okay, but not complete. GH, KH, O2 is missing. Very detailed information about the biotope – really great!

Nathan K. Lujan: Little description and/or illustration of the natural underwater aquascape and habitat. Good lists of species and decent references.