Male U. vocans borealis and U. lactea lactea were distinctly segregated on the upper
shore of the sandy beach at Lok Wo Sha (Table I). U. lactea lactea occupied only
region 1 of the upper shore, whereas small size U. vocans borealis were found primarily
in regions 2 and large size U. vocans borealis in region 4 of the shore. Both Uca
species were absent from region 3 on the beach. Figure 2 shows the sediment median
diameter, water content and total organic carbon in the 4 regions of the upper shore.
Region 3 had the highest median sediment diameter (480 mm) and total organic