The results showed an average diversity index ðH0Þ
and evenness ðJÞ was 2.47 and 0.57 respectively in
summer. Diversity indices varied from 1.36–3.55, and
the evenness index from 0.32–0.83 (Table 1). The highest
diversity index appeared at the bottom of station 9, and
the lowest was at the subsurface of station 16. Overall,
higher values were near Neilingding Island and lower
values in the southeastern waters of Hong Kong; distribution
of phytoplankton species was uneven at different
regions and water layers because of some key
species differences (i.e. Skeletonema costatum, etc.) and environmental changes. In winter, although the evenness
was almost the same as that in summer, biodiversity was
much less than that in summer (Table 1). The lowest
biodiversity appeared in the bottom layer of station 2,
while the highest appeared at the bottom layer of station
27. The average phytoplankton diversity of waters near
Neilingding Island was 1.92 which was lower than waters
near Hong Kong, at an average of 2.12.