EMMA – Environmental monitoring and modelling of aquaculture in risk areas of the PhilippinesAkvaplan-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 monitoringAkvaplan–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 determinethe 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 equipmentGovernment 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.

Modelling of aquaculture impactsHydrodynamic models were developed for predictingaquaculture 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.