3. Results
3.1. PO activity in mature oysters exposed to jets, chisel and jets+chisel
Two-way ANOVA comparing all three treatments against the control
over time showed there were significant differences in PO activity over
time (p=0.001) but not between treatments (p=0.391). One-way
ANOVAs showed that PO activity was significantly lower than controls
(by 56%) in oysters treated by chiseling after 48 h (Fig. 2; p=0.016).
Phenoloxidase activity in oysters treated with jets and chisel+jets
was also lower than controls (43% and 40% respectively). However,
one-way ANOVAs showed that these responses were not statistically
significantwhen compared to controls (jets, p=0.059 and jets+chisel,
p=0.060). Ninety-six hours after treatment, PO activity was significantly
greater than controls in oysters subjected to jets+chisel (p=
0.001; 2.61 fold increase), as well as in oysters treated with jets alone
(p=0.004, 2.06 fold increase). Oysters treated by chiseling only also
showed elevated levels of PO activity (1.74 fold increase). However,
this increasewas not statistically significantwhen compared to controls
(p=0.056). One-way ANOVAS also showed that PO activity in controls
did not differ significantly over time,while treatment with the jets, and
jets+chisel, had significantly higher PO activity at 96 h relative to the
0 h time-point (p=0.006 and p=0.004 respectively).