Chloride cell morphometrics of Common carp, Cyprinus carpio, in response to different salinities

Abstract

Salinity plays an important role in the survival, metabolism, and distribution of fish during development. The successful establishment of species in a given habitat depends upon the ability of each developmental stage to cope with salinity via osmoregulation. The present study was conducted to assess the effect of salinity on number and size of chloride cells or mitochondria rich cells and their relation to osmoregulatory ability in Cyprinus carpio, a freshwater (FW) fish. No mortality occurred when the Common carp was gradually transferred into brackish water. Branchial chloride cell numbers decreased after brackish water exposure, whereas a gradual increase was observed in chloride cell size. Chloride cells exist in both FW and brackish water. The number of chloride cell fish in 9 ppt salinity was greatly significant (p < 0.05) when compared with other treatments, while chloride cells with larger size were observed in 12 ppt salinity (p < 0.05). Hence, our data indicate that in culture conditions, adult Common carp can survive successfully in brackish water with salinity of up to 9 ppt.