The principal objective of the present study was to compare the
osmoregulatory and endocrine responses of euryhaline Mozambique
tilapia to acute changes in salinity with those of the less
SW tolerant Nile tilapia. Marked increases in plasma osmolality
were observed in both species at 2 h after transfer from FW to
SW. According to Wang et al. (2009), their strain of Mozambique
tilapia were also unable to survive for more than 6 h after direct
transfer from FW to SW, which resulted in a nearly twofold increase
in plasma osmolality. On the other hand, transfer from
BW to SW did not induce a change in plasma osmolality in Mozambique
tilapia, while in Nile tilapia, this transfer was associated with
a marked elevation in osmolality to above 450 mOsm. In the present
study, when BW-acclimated Mozambique or Nile tilapia were
transferred to FW, they showed no sign of distress, and plasma