Alteration in branchial NKA and NKCC ion-transporter expression and ionocyte distribution in adult hilsa during up-river migration.

Hilsa (Tenualosa ilisha) is a clupeid that migrates from the off-shore area through the freshwater river for spawning. The purpose of this study was to investigate the involvement of branchial Na/K-ATPase (NKA) and Na/K/2Cl cotransporter (NKCC) in maintaining ionic homeostasis in hilsa while moving across the salt barriers. Hilsa, migrating through marine and brackish waters, did not show any significant decline in NKA activity, plasma osmolality, and plasma ionic concentration.