The impact of sewage effluents on the fecundity and survival of Eurytemora americana in a eutrophic estuary of Argentina
BERASATEGUI, A.A.; BIANCALANA, F.; FRICKE, A.; FERNANDEZ ?SEVERINI, M.D.; UIBRIG, R.; DUTTO, M.S.; MARCOVECCHIO, J.; CALLIARI, D.; HOFFMEYER, M.S.
ESTUARINE COASTAL AND SHELF SCIENCE
ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD
The present study shows the results of laboratory experiments addressing the effects of different waterqualities on E. americana's fecundity and survival. The study was carried out with cultured females,incubated under different water qualities and controlled conditions during ten days (7 ± 2 C, 14 h light,salinity of 32 ± 2, Tetraselmis sp. and Nannochloropsis sp. as food). Four treatments were established:P ¼ subsurface water from sewage plume of Bahía Blanca city, D ¼ the dissolved phase of P, I ¼ bottomwater in the sewage discharge point of Bahía Blanca city, and C ¼ water from the low-impacted area ofMonte Hermoso, used as a control treatment. Egg production, number of nauplii, number of faecalpellets, survival and fertility-state of females were evaluated. The differences and relationships amongcopepod factors, environmental variables and pollutants levels (cadmium, lead, copper, zinc, chrome andammonium-phosphate dissolved), were analysed among treatment using non-parametric multivariateanalysis. The copepod factors showed a negative association with pollutants levels and the turbidity. Nomortality was observed in C, P and D treatments, whereas 100% mortality was observed in treatment I.Females from C, showed the highest egg production (22.6 ± 6.5 egg/female.clutch), as well as gonadsregeneration and a second egg laying. Egg production, number of nauplli and faecal pellets were similarfor P and D treatments, but significantly lower than those registered in C. In P treatment, only 40% offemales showed regeneration of their gonads for a second egg laying (12.4 ± 2.9 egg/female.clutch) andin D treatment, no female regenerated their gonads for a second egg laying (12.5 ± 3 egg/female.clutch).The results indicate that bioavailable contaminants from dissolved phase of sewage effluent reduce thefertility in Eurytemora americana, while the bottom water at the sewage discharge site is undoubtedlylethal for this species.