Fish diversity in the Río de la Plata and adjacent waters: an overview of the environment influence on its spatial and temporal structure

JAUREGUIZAR, A.J; SOLARI, A.; CORTÉS, F; MILESSI CONRADO, A.; MILITELLI, M I; CAMIOLO, M. D; LUZ CLARA, M.; GARCÍA, M.

JOURNAL OF FISH BIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2016 vol. 89 p. 569 - 600

0022-1112

In this paper we reviewed and analyzed, with emphasis in the functional guild classification,fish diversity and the main environmental factors affecting the spatial distribution of species, life history stages and community structure in the Río de la Plata (RdP) and adjacent waters. The functional guild classification indicated that most of species in the RdP were marine stragglers, zoobenthivores and oviparous species; although in biomass it was dominated by estuarine species. Salinity had a stronger influence than temperature on the spatial pattern for all life stages, being shallower and fresher waters the preferred habitats of neonates and juveniles. During the breeding season (spring-summer), adults showed an intrusion into the inner part of RdP or to its adjacent nearshore waters from the offshore waters to spawning or mating areas, respectively. Variations in river discharge and wind patterns greatly affected the spatial coverage of estuarine water, which ultimately influenced the domain of main life history stages ((juveniles or adults) for both marine or estuarine fishes, as well as species and fish assemblages composition. The strong environmental gradient restricts some species and life history stages to a particular section and defines three main fish assemblage areas. The composition of fish assemblage is indicative of the recruitment of freshwater and marine40 species to estuary in opposite sense, which was determined by the vertical stratification. Seasonal changes in the species composition were related to migration as a result of salinity and temperature variations and/or reproductive migrations to spawning and mating areas. This overview revealed that the RdP is under environmental variations that are likely to produce modifications in fish distribution and abundance affecting its availability for fisheries. This context plus fish stocks declines and changes in exploitation patterns could amplify the magnitude of the variations in the fisheries resources availability and 46 affect the sustainability of fishing communities.