Long-term exposure of the red cherry shrimp Neocaridina davidi to diclofenac: impact on survival, growth, and reproductive potential

Abstract

The current study was aimed at studying the long-term effects of diclofenac on the freshwater shrimp Neocaridina davidi, concerning survival, somatic growth, and reproduction. To this study, both ovigerous females and males of this species were exposed for 63 d to 0 (control), 0.1, or 1 mg/L of diclofenac. At the highest concentration, significant mortality was detected, and the somatic growth of females was significantly decreased. The percentage of females with a second spawn, observable from day 45, significantly increased at 1 mg/L, while the time between spawns was significantly reduced at both concentrations assayed. However, the gonadal analysis made at the end of the assay in the surviving females showed a significantly lower proportion of advanced oocytes in females exposed to 1 mg/L, as compared to control. Concerning hatching, the percentage of ovigerous females that could have successful hatching was reduced at 1 mg/L of diclofenac, especially for the first spawn. For the second spawn, the number of juveniles hatched from females exposed to 1 mg/L was reduced compared to control; these juveniles also showed a significantly higher incidence of morphological abnormalities, such as hydropsy and underdeveloped appendages. Taken together, these results showed that even when diclofenac was able to produce earlier spawns, the reproductive output of each spawn was reduced. No differences in the spermatophore structure were seen in the distal vas deferens of surviving males.