Assessment of production and water quality impacts of shellfish aquaculture using farm-scale models

Transcription

1 ECosystem Approach for Sustainable Aquaculture ECASA Assessment of production and water quality impacts of shellfish aquaculture using farm-scale models ECASA Stakeholder Conference J.G. Ferreira, A. Sequeira, A.J.S. Hawkins, A. Newton, R. Pastres ECASA Final Meeting, Crete, 17 th -2 th September 27

2 Topics System-scale scale models: overview, drivers System-scale scale models: carrying capacity Farm-scale models: drilling down FARM: People - Planet - Profit Synthesis Slides Guincho, Portugal

3 Loch Creran EcoWin2 model Delft3D hydrodynamic model EcoWin2 ecological model 3 boxes 3 layers Many boxes 2 layers A much coarser grid is used in biogeochemical models than in hydrodynamic models.

4 Validation of growth drivers Loch Creran Box 4 (Oyster Farm) DIN (µmol l -1 ) SPM (mg l -1 ) J F M A M J J A S O N D J F M A M J J A S O N D Phytoplankton (µg Chl a l -1 ) POM (mg l -1 ) J F M A M J J A S O N D J F M A M J J A S O N D

5 Ria Formosa EcoWin2 model inlet N inlet Model boxes inlet inlet 9 boxes 1 vertical layer 4 ocean inlets Water fluxes simulated with the MOHID hydrodynamic model

6 EcoWin2 model Ria Formosa Residence time Water residence time: days units of tracer in all boxes at start Box 1 Box 2 Box 3 Box 4 Box 5 Box 6 Box 7 Box 8 Box 9 e-time e-folding time folding time: time for the concentration in a model box to be reduced by a factor of 1/e, i.e., from an initial concentration of 1% to about 37%

7 Validation of growth drivers BOX 2 Ria Formosa Box DIN J F M A M J J A S O N D Phytoplankton J F M A M J J A S O N D SPM J F M A M J J A S O N D POM J F M A M J J A S O N D

8 Aquaculture areas in Loch Creran (Mytilus edulis) (Crassostrea gigas) 6 % of the area is under cultivation BOX 1 (M) 1 (O) 3 (O) 4(O) 6 (M) 6 (O) 8 (O) 9 (O) Total Area (ha) Aquaculture % area

9 Loch Creran EcoWin2 model Synthesis of outputs (stable model) Pacific oyster Box Aquaculture TPP APP area (ton TFW) Total/Average 31.5 ~3 9.8 Higher APP values were obtained in the upper reaches of the Loch. Values for validation of boxes closer to the river were not available.

10 Loch Creran EcoWin2 model Oysters: Seed, harvest and Average Physical Product (APP) (Stable model - year 1) Ton TFW APP Seeded Harvested Box 1 Box 3 Box 4 Box 6 Box 8 Box 9 BOX APP Weight at harvest > 5 g Total production ~ 3 ton APP ~ 9.5

11 Loch Creran Biodiversity scenario Oyster production with and without wild species Production (tons) Weight (g) Length (cm) Indicator % reduction Production 13% Individual weight 27.6% Individual length 1.3% Without wild species With wild species The model indicates that oyster production is higher when competition for food due to wild species is not considered. 1 year run

12 Aquaculture areas in Ria Formosa 7 % of the area is under cultivation Ruditapes philippinarum (Manila clam) BOX Area (ha) Aquaculture % of area

13 Clams BOX Ria Fomosa: Individual length and weight Culture period April to September Ruditapes philippinarum (Manila clam) 13.5 (cm) (g) Clams mean length ~ 3.7 cm mean weight ~ 11.6 g Length (cm) Weight (g)

14 Ria Formosa EcoWin2 model Total production Total Production (ton TFW) Model starts stabilising after year Year SIMULATION: Total production: 4 ton of clams Clam harvest Clam seed Production in Ria Formosa has been fluctuating in recent years between 3 and 4 ton y -1 (Pers. com. President of the Algarve Aquaculture Association)

15 Productivity in Ria Formosa Comparison between model results in clam cultivation areas and potential productivity in different areas of Ria Formosa Tons (TFW) APP Average Physical Product APP APP Harvest Seed Box 4.8 Potential productivity

16 Ria Formosa - Average Physical Product APP obtained in EcoWin2 model for Manila clam culture Potential productivity in Ria Formosa

17 Farm-scale conceptual diagram 养殖区概念模型 Farm length Width Current Shellfish Current Chl a Depth n-1 n Chl a POM POM Sections

18 FARM results Loch Creran Ria Formosa Box 4 (aquaculture = 16.5 ha) Farm layout: 26 m x 8 m 5 m depth Culture practice: Pacific Oyster ~1 ton ha -1 (5 ind m -2 ) 73 day cultivation Box 7 (aquaculture = 11.4 ha) Farm layout: 71 m x 16 m 3 m depth Culture practice: Manila Clam 1.35 ton ha-1 (9 ind m -2 ) 18 day cultivation

19 Loch Creran Model outputs

20 TPP (tons TFW) Stage I Loch Creran Economic Analysis I Stage II Optimisation 13 ton VMP = MPP.P o VMP = P i For P i = 2% P o, MPP =.2 Stage III TPP APP Seed (tons TFW) C. gigas, 73 day cultivation period, drivers from EcoWin2 MPP APP and MPP (no units)

21 Loch Creran Economic analysis II Seed TPP APP MPP VMP TR TC Profit (ton) (ton) (k ) (TVP k ) (k ) (k ) Price of input (P i ) = 1 kg -1 ; Price of output P o = 5 kg -1

22 Ria Formosa Economic Analysis TPP (tons TFW) Stage I Stage II Optimisation 353 ton VMP = MPP.P o VMP = P i For P i = 1% P o, MPP =.1 Stage III TPP APP MPP 2 4 Seed (tons TFW) R. philippinarum, 18 day cultivation period, drivers from EcoWin APP and MPP

23 Ria Formosa Model Scenarios Seed = 15.3 tons Cost = 15.3 k Nitrogen TPP APP TR Profit Chl a DO ASSETS loading (ton) (TVP k ) (k ) (µg l -1 ) (mg l -1 ) Standard x x x Notes: Price of input (P i ) = 1 kg -1 ; Price of output P o = 1 kg -1

24 Loch Creran

25 Ria Formosa

26 Loch Creran Final comments Ria Formosa The recipe: : Field data + Experiments + Models = System-scale scale and farm- scale carrying capacity assessment (add databases, GIS and scaling); The toolbox: : (i) System-scale scale models which include watershed drivers and pressures, biodiversity, etc. (ii) Farm-scale models driven by the former, and/or by measured data. These models use ShellSIM to simulate individual i growth. Models are deployed on the web or are desktop-based for longer run times; The applications: : (i) System-scale scale - Management level decision-support support for licensing thresholds, agriculture inputs, WFD and Marine Strategy compliance, stakeholder consensus; (ii) Farm-scale: Screening models for determining optimal siting, culture densities, profit maximisation, eutrophication status and nutrient emissions trading and valuation.