Vulnerability of pejerrey Odontesthes bonariensis populations to climate change in pampean lakes of Argentina

Abstract

The vulnerability of the pejerrey Odontesthes bonariensis population in Lake Chasicó was assessed under different climate change conditions. During the sampling period, the water temperature was adequate for fish reproduction and to sustain an adequate sex ratio. Climate-driven higher temperatures, however, may severely distort population structure and cause drastic reduction or local extinction of stocks. Lake Chasicó can be classified as eutrophic with clear waters and cyanobacteria that regularly cause fish mortality were identified as Nodularia spumigena and Oscillatoria sp. Global warming may strengthen the effects of eutrophication (e.g. toxic blooms or anoxia). Since many Cyanophyta species tolerate higher temperatures better than other algae, toxic blooms could increase. Furthermore, cyanobacteria have low nutritional value and could decouple the low-diversity food web. Lake Chasicó has currently the salinity optimum (c. 20) for the development of the early life-history stages of O. bonariensis. Climate change, however, is likely to amplify the intensity of droughts or inundations. Floods can endanger O. bonariensis development due to its sub-optimal growth at low salinity and droughts could increase lake salinity and also temperature and nutrient concentration. In order to reduce some of the effects of climate change on the O. bonariensis population in Lake Chasicó, integrated basin management based on an eco-hydrological approach is proposed.

Dietary phosphorus requirement of pejerrey fingerlings (Odontesthes bonariensis)

“…The pejerrey (Odontesthes bonariensis; Valenciennes [Atheriniformes, Atherinopsidae]) is a native species from Southern Brazil distributed over numerous water bodies around the world (Kopprio et al, 2010).…”

Exceptional lipid storage mode of the copepod Boeckella poopoensis in a pampean salt lake, Argentina

“…The accumulation of 18:4(n-3) in zooplankton is consistent with the occurrence of small flagellates as an important food source. The tendency of these markers coincided generally with the abundance of phytoplankton assemblages in Lake Chasicó (Kopprio et al 2010).The most striking feature of Boeckella poopoensis lipids was the extraordinary accumulation of the 20:4(n-3) fatty acid in winter, reaching an average value of 12% of total lipids in the winter of 2007 and with a maximum of 16% in August 2007. This fatty acid correlated significantly with 18:4(n-3) (r = 0.83, p < 0.001) but was detected only in trace amounts in seston.…”

Sundarban mangroves: diversity, ecosystem services and climate change impacts

“…Extreme high temperature may inhibit growth, behaviour, reproduction of these vulnerable aquatic organisms. Additionally, the larvae and juveniles of many estuarine and marine fishes and higher organisms usually prefer to grow in the shallow micro-environments and food-rich mangrove wetlands, which may become an unsuitable due to the extreme temperature mediated changes in the primary production and nutrient availability (Kopprio et al, 2010). On the other hand the ENSO-mediated floods can endanger the species adapted to high salinity and favor the low-salinity tolerant species.…”

“…The lower food quality could signify lower abundance and growth rate for the zooplankton and thus, may be detrimental to fishes (Kopprio et al, 2010). In addition to toxic effects, increasing plankton biomass can potentially also generate anoxia, with subsequent large-scale decay of phytoplankton populations, followed by microbe-mediated nutrient enrichment in coastal surface water (Manna et al, 2010).…”