3.3. Tidal rhythms of digestive enzyme activities
Temporal variations in enzyme activities in the digestive gland are shown in Fig. 7. In
spring tides, only the activity of a-amylase (A ) showed significant correlation DG
(P , 0.05) with tides, while both the a-amylase and cellulase activity (C ) and the sum DG
of them (AC ) were correlated with tides ( DG P , 0.001) during neap tides. There was no
significant correlation (P . 0.05) between the activity of the a-amylase (A ), cellulase CS
(C ) and the summation of the a-amylase and cellulase (AC ) in the crystalline style CS CS
(Fig. 8) and tides. The activity of a-amylase in both the digestive gland and crystalline
style was higher than that of cellulase. There was no significant change (P . 0.05) in the
wet weight or protein content of the crystalline style during both spring and neap tides
(Fig. 9)