3. Results and discussion3.1. Phyto

3. Results and discussion
3.1. Phytoplankton
The exclusive use of physicochemical indicators to assess
the water quality of intensive mariculture system is insuffi-
cient, particularly if there is an investigation into the extent
of the influence of the farm wastewater on the immediate
environs. This observation concurs with previous studies
concluding that the use of traditional water quality indices
to determine the effect of aquaculture effluent on the receiving
environment is mainly limited to areas near to the discharge
point (Samocha and Lawrence, 1995).

The use of phytoplankton biomass as an indicator for
this type of system is sufficient, but it has specific limitations.
Firstly, the total chlorophyll a values may be underestimated
in areas having high macroalgal populations.
The absorption of nutrients by the macroalgae may result
in an underestimated biomass value and, consequently,
an inaccurate characterization of the water quality. The
size fractions of the phytoplankton are important on a
microscopic level in the determination of water quality.
However, the presence of colonial phytoplankton species
may overestimate the contribution of a size class to the
total biomass at that site. Thus, it is important to know
the species composition, as phytoplankton undergoes a
continual succession of dominant species due to dynamic
changes of growth factors like light, temperature, and
nutrient concentrations in an aquatic environment (Goldman
and Mann, 1980; Yusoff and McNabb, 1997; Yusoff
et al., 2002).