Akvaplan-niva conducted a 2-year study in the Philippines to monitor the environmental impacts of aquaculture and develop predictive models. They trained government staff in monitoring equipment use, data analysis, and using models to assess impacts and estimate safe production levels. Baseline surveys were performed in 3 areas, collecting data on bathymetry, water quality, weather, and production levels. Models were developed to predict impacts and estimate carrying capacities based on water exchange, nutrient sources, and phytoplankton growth. The models suggested one area exceeded capacity while another may not, and management measures were recommended to reduce impacts and increase capacities.

1. EMMA – Environmental monitoring and modelling of
aquaculture in risk areas of the Philippines
Akvaplan-niva undertook a 2-year Norad funded research project to investigate the impacts of
aquaculture in the Philippines, to develop predictive models and make recommendations on ways
to mitigate impact. Akvaplan-niva trained Government staff in the operation of the monitoring
equipment, analysis of data collected and the use of models for predictive assessment of impact
and estimation of safe carrying capacity.
Environmental monitoring
Akvaplan–niva undertook 6 baseline environmental
and production surveys in three areas of the
Philippines, Bolinao Bay an enclosed marine bay,
Dagupan, a brackishwater estuary and Taal lake a
large freshwater lake.
These areas had suffered from fish kills in the past.
At the same time as the environmental surveys,
surveys of production were undertaken to determine
the standing biomass of fish, feed fed, food
conversion rate and annual production of the area.
Data collected
 Bathymetry (depth recordings) of the area
 Tidal range and current speed, direction and dispersion
 Physical parameters - Temperature, turbidity, salinity, oxygen, profile through the water
column
 Water quality – chlorophyll, phosphorous, nitrite, ammonia
 Sediment analysis (biological and chemical)
 Weather data wind direction, speed, temperature
Environmental monitoring equipment
Government staff were trained in the use of the monitoring equipment, analysis of the results and
ways to mitigate the impact of aquaculture.
The equipment used for collecting the data was;
 An echo sounder with GPS to collect bathymetry of
the area
 Current meters to collect current speed and
direction
 Drogues for the collection of water dispersion data
 CTDO to collect temperature, turbidity, salinity,
oxygen, profile through the water column
 Water quality analysis in the laboratory to analyse
chlorophyll, phosphorous, nitrite, ammonia
This equipment was donated to the Government Institute.

2. Modelling of aquaculture impacts
Hydrodynamic models were developed for predicting
aquaculture impacts and to estimate safe carrying capacity
for aquaculture.
Determining the characteristics of a water body.
Estimating the water being exchanged with neighboring
water where fish is not grown and hence has higher
oxygen conten. Estimating the intensities and locations of
other nutrient sources that enter considered water body.
Since fish is usually grown close to the coast, impact of land
based sources may be considerable and may cause
smaller carrying capacity for fish grown in aquacultures.
Estimation of phytoplankton growth based on nutrient
concentration from aquaculture and other sources.
Calculate if aquaculture production can be increased
(or should be decreased) until critical phytoplankton concentration is reached.
Figure 1. depicts the process graphically.
Carrying capacity calculations suggested that aquaculture production in the Taal lake and Bolinao
Bay is higher than sustainable carrying capacity, while in Dagupan section of the estuary this is
probably not the case. A series of management measures were suggested to decrease environmental
impact and increase present carrying capacity for each of the considered areas. Since case studies
represent a lake, an estuary and a marine area, the same methods may be applied to many other
localities in the Philippines, hence fulfilling the goal of this project to obtain results and arrive at
methods that can be applied elsewhere.