The experiment was carried out during a normal stocking haul from
Hanka-Taimen Oy in central Finland to the Gulf of Finland. Thus the experiment
included all aspects of transport stress: initial capture and loading,
crowding in the tanks, changes in water quality (during transport water pH
decreases, PC o, and NH3 concentration increase, see e.g. Barton and Peter,
1982), and release. The brown trout (S&no trutta, mean weight 76.2k1.7 g,
mean total length 20.420.1 cm, n = 65) had been starved for 24 h before
transport. During the 14-h transport in 300-l plastic containers the density of
fish was 100 g/l. Throughout transportation the water was oxygenated. The
water temperature was approximately 10%. One half of the fish were transported
in fresh and one half in salt water (NaCl added to fresh water to give
0.6% salinity). During recovery the fish were kept at 12°C in the natural
brackish water of the Gulf of Finland (salinity 0.6%) at TvPrminne Zoological
Station.