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In this study, the toxic effects on the embryos and larvae of the common carp were used as a model to investigate the synthetic pyrethroid pesticide, cypermethrin, which contaminates aquatic ecosystems. Data obtained from the cypermethrin acute toxicity tests were evaluated using the Probit Analysis Statistical Method. The control and eight test experiments were repeated five times. The number of dead embryos significantly increased in response to cypermethrin concentrations 0.0001, 0.001, 0.01, 0.1, 1, 2, 4 and 8 lg l À1 (p<0.05 for each case). The 48 h LC 50 value (with 95% confidence limits) of cypermethrin for common carp embryos was estimated at 0.909 (0.256-5.074) lg l À1 . Dose-response decreases in hatching success were recorded as 87.4, 85.0, 80.2, 71.4, 56.3, 48.6, 38.8 and 23.5%, respectively. The lowest concentration of cypermethrin (0.0001 lg l À1 ) produced a significant increase in the number of dead larvae compared to the control group (p<0.05). The number of dead larvae significantly increased with increasing cypermethrin concentrations exposed for 1-96 h (p<0.05). The highest concentration (8 lg l À1 ) showed the highest larvae mortality. The 96 h LC 50 value (with 95% confidence limits) of cypermethrin for common carp larvae was estimated at 0.809 (0.530-1.308) lg l À1 . The results of the study suggest that low levels of cypermethrin in the aquatic environment may have a significant effect on the reproduction and development of carp.

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In this study, the ages of 76 individuals belonging to the Cyprinion macrostomus (Heckel, 1843) population caught from Murat River near Bing˛l city were determined from six di¡erent bony structures and the level of calcium mineral of each bony structure was measured using an atomic absorption spectrophotometer. The determined element was statistically examined according to the age, length, weight and sex of the ¢sh. The age, length and weight ranges of the ¢sh were found to be 2^6, 12.0^21.2 mm and 16.3^135.3 g respectively. The relationships between the accumulation of calcium in all bony structures and the ¢sh size (both length and weight) were found to be insigni¢cant (P40.05). However, a strong relationship was found between ¢sh weight and accumulation of the mineral in vertebra and otolith. A strong correlation was also found between ¢sh length and accumulation of calcium in the dorsal ¢n ray, followed by the otolith, vertebra and cleithrum bones respectively. Whereas the accumulation of calcium according to the age groups was found to be insignificant for scale and operculum (P40.05), it was found to be signi¢cant for all the other bony structures examined (Po0.05). In conclusion, the accumulation of calcium on some bony structures of C. macrostomus was observed to increase with an increase in age, length and weight of ¢sh, although the increases were not statistically signi¢cant at least for some bony structures (P40.05).

In this study, some biochemical responses of Beta-Cyfluthrin (β-CF), which is a commercial insecticide in Dreissena polymorpha, were investigated. The 96 hour LC50 value of β-CF on D. polymorpha was calculated as 509.62 µg L -1 . D. polymorpha was exposed to subletal concentrations (1/16, 1/8 and 1/4 of LC50 value: 32, 64 and 128 µg L -1 ) of β-CF for 24 and 96 hours. Malondialdehyde (MDA) and reduced glutathione (GSH) levels and Acetylcholinesterase (AChE) enzyme activities were determined in D. polymorpha individuals. In D. polymorpha exposed to β-CF, MDA levels increased compared to control and with increasing concentration. It was determined that GSH level decreased and AChE activity was inhibited compared to control and with increasing concentration.In conclusion, exposure to β-CF resulted in increased oxidative damage and has been found to cause neurotoxicity even at low concentrations.