AquaPark Panabo Stakeholders meeting interim results AquaPark – Norad funded project Planning and management of aquaculture parks for sustainable development of cage farms in the Philippines

AquaPark Panabo Stakeholders meeting interim results TROPOMOD modelling of aquaculture zones Chris Cromey Map and Marine Ltd Out put from AquaPark Aquapark Project Partners –Bureau of Fisheries and Aquatic Resources –Akvaplan-niva AS –Map and Marine Ltd AquaPark Panabo Stakeholders meeting interim results

Model assumptions

AquaPark Panabo Stakeholders meeting interim results Simulation

TROPOMOD modelling approach 3 important aspects: 1.How severe is the impact – what is the maximum impact underneath cages? 2.How far to the boundary of the impact? (Allowable Zone of Effect) 3.How can husbandry practices be optimised to use the zone most productively? Objectives Predict if impact is SEVERE underneath cages as shown by this deposition footprint Zone colour Predict distance to boundary of MODERATE impact Zone colour Edge of Park

Maintain enough spacing between cage rows so that remediation of sediments can take place – impact should be LOW between rows in each zone Maintain enough space between cage rows to prevent reduction of currents by high aggregation of cages Zone colour TROPOMOD modelling Approach

Encourage careful feeding, so that there is less waste feed and less wastage of money Encourage better quality feed: Feed digestibility is increased Less feed is needed Better quality feed also breaks up less, so more goes to growth Distance between parks Prevent overlap of impact by predicting the extent of the zones – e.g. 600 m between zones for this site TROPOMOD modelling Approach

AquaPark Panabo Stakeholders meeting interim results Panabo sediment trap model validation studies Objective – to measure flux (deposition) of waste feed and faeces under cages and compare with model predictions – this helps us to verify the model predictions and test different scenarios Sediment traps were deployed in Spring 2010 survey: One transect for Milkfish (0 metres from cage, 10 m and reference) One for Grouper (0 metres from cage, 10 m and reference) Chris Cromey – EMMA2 project modeller using data from Akvaplan and BFAR survey teams

AquaPark Panabo Stakeholders meeting interim results Sediment trap model validation study – method for deploying sediment traps 75 cm H:D = 5:1 ratio Sea bed 1. Deploy traps 2. Retrieve, filter, dry solids 3. Calculate observed flux (total waste feed and faeces in traps = grams per m 2 bed per day) 4. Compare with TROPOMOD model Cage Current

AquaPark Panabo Stakeholders meeting interim results TROPOMOD model – method Cage positions were obtained from recent Google Earth image Feed ration for cages obtained from AquaPark production survey Production survey results summarised to include modelling of different stages of Milkfish monoculture (starter, grower and finisher), as well as other species (Milkfish-Siganid polyculture, Grouper, etc.)

AquaPark Panabo Stakeholders meeting interim results TROPOMOD model – method Settling velocity of feed obtained from EMMA2 project pellet break up experiments and PHILMINAQ project experiments Settling velocity of Milkfish faeces from PHILMINQ project Depth obtained from BFAR surveys Uneaten feed (27%), digestibiity (49%) and water content (9%) – data from PHILMINAQ project

AquaPark Panabo Stakeholders meeting interim results TROPOMOD model – method Current meter data from BFAR surveys used TROPOMOD set up with information and used to predict flux of waste feed and faeces (grams per m 2 bed per day) for Panabo Aquaculture park

AquaPark Panabo Stakeholders meeting interim results TROPOMOD predicted flux (deposition) of waste feed and faeces for Panabo The colours show different amounts of flux Sediment trap transects: Grouper (traps are in 6 m depth) Milkfish transect (traps are in 27 m depth) Reference traps Model predictions Higher flux and predicted impact in the inshore areas

AquaPark Panabo Stakeholders meeting interim results Milkfish sediment trap transect Problem – cage locations taken from recent Google Earth image and trap locations taken from survey do not match as station M0m should be at cage edge, and M10m should be 10 m from cage Solution – make minor adjustments to cage/station positions in model so they match Two stations (three traps at each) Feed ration = 50 kg per cage per day

AquaPark Panabo Stakeholders meeting interim results Grouper sediment trap transect These cages are in shallower water and feed ration is 10 kg per cage per day, which is less than for Milkfish monoculture Two stations (three traps at each)

AquaPark Panabo Stakeholders meeting interim results Milkfish – comparison of observed flux and predicted For both the 0 m and 10 m stations, the model slightly over-predicted flux Note the variation between traps at the same station Traps are adjusted for background sedimentation

AquaPark Panabo Stakeholders meeting interim results Grouper – comparison of observed flux and predicted Model predictions of flux were satisfactory for Grouper Note the variation between traps at the same station Traps are adjusted for background sedimentation

AquaPark Panabo Stakeholders meeting interim results All sediment trap data collected by Cromey et al. at SAMS Panabo measurements were less than 20 g m -2 d -1, which is at the low end of measurements taken

AquaPark Panabo Stakeholders meeting interim results Conclusions and next steps TROPOMOD predicted flux satisfactorily for Grouper, but over-predicted for Milkfish – we will look at this more carefully after refinements Modelling of the whole park showed higher impact in the inshore areas, where the depth is shallower and dispersion is lower Modelling the whole park requires care, as cage locations and feed inputs vary widely across the park depending on the source of data – for management scenarios, some randomness can be introduced to account for this

AquaPark Panabo Stakeholders meeting interim results Conclusions and next steps Next steps are to model the park by organising species into zones Identify areas for oysters and seaweed Further refinements of the modelling are needed, incorporating as much information from the Spring 2010 surveys as possible