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Ecosim Beth Fulton 2012 Ecosim Time dynamic Ecopath = initial conditions Define − Duration − Environmental drivers − Contaminants option − Fleet dynamics option ECOPATH, ECOSIM and ECOSPACE Ecosim Basic equation dBi gi Qji Qij Ii Mi Fi ei Bi dt j j ECOPATH, ECOSIM and ECOSPACE Ecosim – Group info Flow-control: (top-down to bottom-up) − Sensitive parameter − check with sensitivity analysis, time series fitting, twomodel comparison, Bunfished/B0 , Fmax/M) Feeding time adjustment rate Predator effect on feeding time − 1.0 = stop feeding if predation risk high − 0.0 = ignore predation risk high Other mortality (top predators sensitive to this) Catchability Environmental tolerances Ecosim – Group info ECOPATH, ECOSIM and ECOSPACE Ecosim Covers… Ontogenetic changes (growth vs reproduction, egg production) Feeding related changes (diets, feeding time, handling time) Trophic effects (predator/prey dynamics) ECOPATH, ECOSIM and ECOSPACE Ecosim – Forcing functions Forcing functions (seasonal, long-term, environmental, productivity…) ECOPATH, ECOSIM and ECOSPACE Ecosim Covers… Drawn or imported Apply to different groups / interactions on ‘Apply FF’ Primary productivity over time (apply to primary producers or their interactions) ECOPATH, ECOSIM and ECOSPACE Ecosim - Mediation Mediation effects ECOPATH, ECOSIM and ECOSPACE Ecosim - Mediation How you put in non-trophic interactions − done in very similar way to forcing (apply using ‘Apply FF’ sheet but select mediation option) Ecosim – vulnerabilties Vulnerability = rate become vulnerable to predators ECOPATH, ECOSIM and ECOSPACE Ecosim – vulnerabilties Parameterise which wins out hunger or fear Depending on parameterisation can create many alternative functional responses (LV, Holling types, ratio dependent etc) ECOPATH, ECOSIM and ECOSPACE Ecosim – vulnerabilties Vulnerable prey Predator P aVP Unavailable prey B-V v(B-V) Available prey V vV B = Total prey biomass; V = Vulnerable prey biomass; v = Behavioral exchange rate; P = Total predator biomass; a = Predator rate of search. Fast equilibration between B-V and V implies V=vB/(2v+aP) Ecosim – forecasts fishing effects Biomass/original biomass Fishing effort over time Ecosim – check Ecopath Output ► Run Ecosim − is everything flat (or changing according to the Biomass Accumulation)? − if ‘wild’ look at balance, small plankton, discard effects ECOPATH, ECOSIM and ECOSPACE Ecosim – check Ecopath Input ► Fishing rate − pick fleet − sketch a disturbance (fishing rate change) ECOPATH, ECOSIM and Ecosim – check Ecopath Go to Output and rerun − if everything OK the trajectories come back to initial value (eventually) − are all groups reacting at the speed you expect them to? Ecosim – using past time series Relative or absolute biomasses Mortality rates, F, Z, catches Effort data Forcing factors (primary productivity) Incorporates goodness of fit measure (weighted SS) Anomaly fitting (productivity, recruitment) Fit to data Similar to single species assessment Compare time series Ecosim – sensitivity analysis Group info parameters Vulnerabilities − high v = Lotka-Volterra like with small perturbations = top-down − low v = bottom-up − explore settings to edge of stability − fit to data Ecosim – sensitivity analysis Remove fishery − check system evolution − should maintain all species − recheck vulnerabilities (higher less stable) − fit to data Ecosim Extras Fisheries policy search (economic, social, biological objectives) Ecosim Extras - MSE Management Strategy Cycle (reproducing management cycle) Ecosim Extras - MSE Enter options, regulations etc Ecosim Extras - MSE Multiple runs to see probability of outcomes Ecosim Example Ecosim Example Catch and effects at different levels of depletion Example Compared to other models Thank you