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Add To Calendar 27/04/2016 13:30:0027/04/2016 13:50:00America/ChicagoAsian-Pacific Aquaculture 2016THE USE OF NUMERICAL MODELLING TOOLS TO DETERMINE THE CARRYING CAPACITY AND SUSTAINABILITY OF FUTURE LARGE SCALE LOBSTER FARMING, SABAH, MALAYSIA   Diamond 2The World Aquaculture Societyjohnc@was.orgfalseanrl65yqlzh3g1q0dme13067DD/MM/YYYY


Marjorie Lim*, Neil D. Hartstein, Melissa M. Matthew, Tania Golingi, Tony Chiffings and Kim P. Jakobsen
11th Floor Wisma Perindustrian, Jalan Istiadat, Likas, 88400 Kota Kinabalu, Sabah, Malaysia

A numerical modelling study was conducted to determine the carrying capacity of a proposed lobster Aquaculture Industry Zone (AIZ), northwest of Semporna Town, Sabah, Malaysia. This study enabled the AIZ to be divided into a number of production zones, with each zone assigned a specific sustainable production tonnage (carrying capacity). The carrying capacity was based primarily on variables such as water depth, nutrient exchange, location of sensitive receptors and flushing (retention time).

The modelling focused on potential water column and seabed impacts of the proposed farming with special emphasis given to sensitive receptors such as corals, seagrass beds and mangroves. The modelling was undertaken using the MIKE by DHI numerical modelling suite, combined an ecological/food web model along with a well calibrated hydrodynamic model. The hydrodynamic model was calibrated against current meter measurements while the ecological model was calibrated against a number of seabed and water column parameters. This data was collected as part of a baseline survey for an EIA and included chlorophyll-a, ammonium, nitrate, seabed total organic carbon and dissolved oxygen with measurements taken across more than 30 sampling stations. Baseline sampling was also conducted within the surrounding catchments (major rivers and streams).

Two main types of waste products were considered in the model. These wastes were organic material in the form of faeces and uneaten feed and also the metabolic wastes from the lobster itself, in this case, ammonium. In addition nutrient loadings from the local catchments were also included within the model. Water column impacts were compared against known thresholds (i.e. levels of nutrient increase that are likely to have adverse impacts on corals). A number of scenarios were undertaken to ensure that production levels have no adverse impacts on sensitive receptors. The deposition impacts of the faeces were also assessed in this study. The depositional footprint information derived from the modelling tool was used to calculate a buffer zone between future farm locations and sensitive habitats such as corals. Depositional modeling indicates that in locations with low current flow the predicted organic deposition was restricted beneath the farm cages. Whereas areas with stronger water movement, organic carbon waste was more widely spread.

Modelling studies combined with in-situ measurements are a very useful tool in determining the carrying capacity of any water body for sustainable aquaculture production.

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