Fish assemblage of a Pampean shallow lake, a story of instability

Abstract

Pampean lakes are characterised by the alternation of flood and drought periods, but little is known about its effects on fish assemblage in an extended temporal scale. This study analyses the temporal variability of the fish assemblage in Chascomús Lake, and discusses the role of temperature and precipitation as potential drivers of fish composition shifts. Data acquisition was based on experimental fishing performed from 1999 to 2013 and from historical fishing records. Two alternative fish assemblage configurations were identified by cluster analysis. Odontesthes bonariensis, Parapimelodus valenciennisand Cyphocharax voga were the dominant species, which accounted for 70-80% of the relative abundance. The species O. bonariensis showed temporal fluctuations in its representativeness, changing from dominant to almost absent, whereas C. voga and P. valenciennis changed their abundance following a similar pattern along time. When historical data were considered, Platanichthys platana appeared as the fourth most relevant species. Precipitation, critical temperatures and fish mortalities were identified as the main drivers of species abundance shifts. This study highlights the importance of long-term assessments to understand the influence of climatic factors and the need to maintain or restore natural ecological processes as the basis to support dynamic sustainable fisheries in Pampean shallow lakes.

Invasion status of the common carp Cyprinus carpio in inland waters of Argentina

“…(), represents the most suitable trophic state for C. carpio population development. Furthermore, the existence of extraordinary rains and floods, together with canalisation for alleviating inundation problems, has led to the connection of most of the sub‐basins within the Río de la Plata River system, representing another feature which facilitates fish movement among water bodies in this area (Colautti et al ., ). In addition, extraordinary flooding events, particularly in 1982 and 1997, could have improved C. carpio reproductive success by generating adequate environments for spawning activity.…”

Chemically-induced plasticity in early life history ofPalaemon argentinus: are chemical alarm cues conserved within palaemonid shrimps?

“…Water transparency, along with changes in macrophyte abundance, has been shown to affect trophic interactions in these shallow lakes (e.g. Colautti et al, 2014;González Sagrario et al, 2009;Sosnovsky et al, 2010). Fish diet analyses support the relevance of the littoral zone as a foraging area with an estimated contribution of littoral carbon accounting over the 80% of the biomass ingested by pelagic fish species (e.g.…”

Feeding ecology of the siluriform Pimelodella laticeps Eigenmann, 1917 in a Pampean stream from Argentina

“…in Argentine freshwater ecosystems, although certain other species have shown better acclimation to colder conditions (Colautti et al, 2015). Baigún et al(2002) attributed the absence of P. laticeps in northern Patagonia to its low tolerance to cold temperatures.…”