Rearing temperature had a significant effect on the occurrence of
apparent lordosis also at harvest time, and fish in the 20 °C group
exhibited significantly higher percentage (Table 1; Fig. 5). In both
temperature treatments, lordosis frequencies had decreased signifi-
cantly (P b 0.01, Table 1) and the 15 °C treatment group appeared to
be lordosis-free, based on external image evaluation. On the contrary,
of the fish reared initially at 20 °C, 17.5 ± 1.9% had heavy lordosis
(100–152° lordosis angle) and 20.6 ± 7.6% mild lordosis (152–166°
lordosis angle). Mild lordosis led to marketable fish (Fig. 5B), but
heavy lordosis rendered the fish unmarketable (Fig. 5C). Fish exhibiting
mild or heavy lordosis did not differ in mean WW from normal fish,
either in the 15 or 20 °C treatment groups (P = 0.45, Fig. 6).
Mortalities were monitored throughout the study and results were
grouped in periods representing hatchery rearing (0–74 dps), nursery
rearing (75–145), 1st year grow out (165–307 dps) and 2nd year
grow out (308–715 dps). With the exception of the nursery period,
there were no significant differences in mortalities between the
two temperature treatments (two-way ANOVA, P = 0.09) and mean
(±SEM) survival for both treatments were 94 ± 0.9% for the hatchery
period, 97 ± 0.3% for the 1st year grow out period and 98 ± 0.8% for
the 2nd year grow out period. Regardless of treatment, survival during
the nursery period was significantly lower than for all the other periods
(ANOVA, DNMR, P ≤ 0.01), and was also significantly different between
the 15 °C group (55 ± 4.3%) and 20 °C group (75 ± 9.9%)
Rearing temperature had a significant effect on the occurrence ofapparent lordosis also at harvest time, and fish in the 20 °C groupexhibited significantly higher percentage (Table 1; Fig. 5). In bothtemperature treatments, lordosis frequencies had decreased signifi-cantly (P b 0.01, Table 1) and the 15 °C treatment group appeared tobe lordosis-free, based on external image evaluation. On the contrary,of the fish reared initially at 20 °C, 17.5 ± 1.9% had heavy lordosis(100–152° lordosis angle) and 20.6 ± 7.6% mild lordosis (152–166°lordosis angle). Mild lordosis led to marketable fish (Fig. 5B), butheavy lordosis rendered the fish unmarketable (Fig. 5C). Fish exhibitingmild or heavy lordosis did not differ in mean WW from normal fish,either in the 15 or 20 °C treatment groups (P = 0.45, Fig. 6).Mortalities were monitored throughout the study and results weregrouped in periods representing hatchery rearing (0–74 dps), nurseryrearing (75–145), 1st year grow out (165–307 dps) and 2nd yeargrow out (308–715 dps). With the exception of the nursery period,there were no significant differences in mortalities between thetwo temperature treatments (two-way ANOVA, P = 0.09) and mean(±SEM) survival for both treatments were 94 ± 0.9% for the hatcheryperiod, 97 ± 0.3% for the 1st year grow out period and 98 ± 0.8% forthe 2nd year grow out period. Regardless of treatment, survival duringthe nursery period was significantly lower than for all the other periods(ANOVA, DNMR, P ≤ 0.01), and was also significantly different betweenthe 15 °C group (55 ± 4.3%) and 20 °C group (75 ± 9.9%)
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