Fish were transported to the laboratory Žduration of 4 h. at a density of 100 fishrm3
in tanks kept under half-shadow conditions and with a salinity of 5 ppt NaCl.
Temperature during transport was 19.6"0.58C and the pH was 6.8"0.3. Aeration was
provided to maintain dissolved oxygen near saturation levels Ž7.6"0.4 mgrl.. Immediately after arrival in the laboratory, groups of fish were stocked at 50 fishrm3 in two
indoor tanks with water at 0 and 5 ppt NaCl and allowed to recover for 1 week. A third
group held at a salinity of 20 ppt NaCl for recovery after transport was added to the
second experiment after the results of parallel experiments showed that fish transferred
to this salinity had lower plasma cortisol and glucose levels compared with those at the
other salinities ŽTsuzuki, 1999.. The water level in all tanks was adjusted according to
the number of fish removed due to sampling or mortality to maintain a constant rearing
density. The rearing water during the recovery periods was exchanged daily at a make
up rate of 70%. Tanks were inspected every 6–12 h to record temperature and survival
rates.