1. TROPOMOD modelling for optimisation of AquaParks Chris Cromey EMMA2 project modeller using data from Akvaplan and BFAR survey teams Modelling objectives for each AquaPark Predict benthic impact for the existing situation and validate model with survey data Predict benthic impact for expansion/reorganisation Predict optimum location for Integrated Multi-Trophic Aquaculture units Estimate of production and recommendations from modelling viewpoint Other objectives TROPOMOD educational software showing different scenarios of impact

2. TROPOMOD educational software

3. Currents move in different speeds and direction at different depths. Faeces settle more slowly and so are transported further away from cages 0 Current Velocity Source Milkfish waste faeces settle very slowly Fine Coarse Medium Waste feed particles settle quickly

4. Contour map of waste flux Benthic community (grams waste feed and faeces m-2 d-1) -2 -1 grams solids m bed d 75 Severe impact (no animals) 75 15 High impact (some effect) Cages 15 1 Moderate impact 1

5. TROPOMOD validation with sediment traps Cage Current Sea bed 1. Deploy traps 75 cm 2. Retrieve, filter, dry solids H:D = 5:1 ratio 3. Calculate observed flux (total waste feed and faeces in traps = grams per m2 bed per day) 4. Compare with TROPOMOD model

6. TROPOMOD model validation comparison of observed and modelled flux Comparisons between modelled and observed flux for Sual (Offshore Milkfish) and Panabo (Inshore Milkfsh and Grouper) were satisfactory

7. TROPOMOD validation relationships between predicted flux and indicators of impact - Sual Where TROPOMOD predicted high flux, sediments contained higher % of organic material

8. TROPOMOD validation relationships between predicted flux and indicators of impact - Panabo Organic Carbon as also found to be high, where TROPOMOD flux predictions were high

9. Criteria for AquaPark zoning Regular spacing between cage groups to allow flushing Regular spacing between zones to allow flushing No cages near restrictions to allow current flow Only small Milkfish cages or Grouper cages in shallow areas near to shoreline Larger cages (polar circles) in deeper areas away from shoreline

10. Compare with the current situation Current flow restrictions due to high density of cages, with no gaps

11. Criteria for AquaPark zoning - impact Within each zone MODERATE impact (green) or less between cage groups MODERATE impact (green) or less between zones SEVERE impact (grey) under the cages was minimised

12. Suspended/raft culture (e.g. oysters) - majority of the wastes intersect the culture in the top 10 m; these wastes are mostly fine and slow settling Milkfish faeces Criteria for AquaPark zoning IMTA location 18% 5% 0-3m 3% 6% 3-6m 2% 6-9m Reversing current