The exclusion of crabs from the experimental area could
successfully maintain an area free of crab activity (Fig. 2). The
initiation of reproductive season was evidenced by the increase of
courtship activity at the end of the experiment. Chlorophyll a content
of the upper 2 mm surficial sediment from areas with and without
crab activity showed cyclic changes across time (Fig. 2), which could
be explained by one Sine wave component (Table 4). Crab feeding
activity did not significantly influence temporal patterns in Chlorophyll
a content in sediment; both time series had the same frequency,
phase and amplitude (Likelihood Ratio Tests: χ2=0.85, df=3,
p=0.8365).