COLAUTTI Dario Cesar
congresos y reuniones científicas
DIFFERENTIAL GROWTH AND SURVIVAL OF PEJERREY LARVAE (Odontesthes bonariensis) IN TWO PAMPAS LAKES ASSOCIATED TO DIFFERENT LAND USES AND DIFFERENT WATER QUALITY.
CARRIQUIRIBORDE P.; COLAUTTI D. C.; JURADO M.; SOLIMANO P.; RONCO A.; SOMOZA G.
Simposio; VIII Congreso SETAC Latinoamérica. Society of Environmental Toxicology and Chemistry Branch Latin-American; 2007
Eutrophication and pollution are major and increasing problems affecting surface waters. The hypothesis that changes in water quality of pampas lakes associated with specific land uses could be affecting the viability of natural populations of pejerrey was tested. From November-2006 to March-2007, a series of field experiments using different culture densities were conducted in two pampas lakes mainly influenced either by urban (Chascomús Lake, CHA) or extensive rural (Lacombe Lake, LAC) activities. Survival and growth performance of caged newly-born pejerrey, reared during 45d at each lake, were comparatively evaluated in relation to sediment and water quality parameters. Survival was significantly different among lakes, but not between experiments within the same lake, indicating no density dependence. Survival (grand mean±SE, n=4) in CHA and LAC were 10.8±3.8 and 35.3±2.6%, respectively. On the other hand, growth was significantly higher in CHA, presenting standard growth rate values of 3.85±0.65 and 2.81±0.38 %/d, respectively. Significantly higher values of soluble reactive phosphorus and ammonia, and lower values of Secchi were observed in CHA. Levels of NH-NH4 (0.2-1.2 mg/L) in CHA were in the range of the 96h-LC50 reported for pejerrey and other fish species. Greater growth in CHA was consistent with increased production and fish condition reported for nutrient enriched water-bodies. Lakes associated with specific land uses showed differences in water quality parameters that could explain observed differences in the performance of early stages of pejerrey. Keywords: pejerrey, field study, pampas lake, land use, water quality