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Published byJeremiah Richardson Modified over 11 years ago
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Modelling Vertebrates Beth Fulton 2012
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End to End Model
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Difference equation time step assumed (agreed upon) Differential equation instantaneous (or really tiny time slices) D.E.
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Life history ReprodGrowthMetab.MoveAgingMortality
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Biomass Aggregate Biomass Recruitment, Migration & Growth Mortality & metabolism e.g. Ecopath
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Numbers Abundance Recruitment & Migration Mortality
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Age Structure Aging & Growth Recruitment Mortality Stock assessments
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Can be simple (just age structure) Can be complex (spatial, genetic stocks etc) Age Structure
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Disease/Oxygen limitation Vertebrate Reserve Structure Nutrients Detritus Pred C Pred B Pred A Prey C Prey B Prey A Prey availability Gape limitation Reproduction Age structure & Condition
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Basic form: Senescence and disease considered Age structured (age phases; distribution within phases) computationally efficient allows ontogenetic shifts, recovery delay, overfishing effects Gape limited & can starve (condition impacts survival and reproduction) oxygen deficient, starvation or quadratic Atlantis
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Transition matrices Explicit formulations (density & food dependent; sedentary; forced; mixed) Weighting for seasonal migrations (can migrate in & out of model domain) Smooth and interpolate old to new based on cruising speed Kalman filter Vertical movements Movement
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Stock-recruitment relationships Adults Recruits Beverton Holt Fixed # offspring / adult Ricker Reproduction Others = lognormal, plankton-based…
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Stock-recruitment relationships Based on parental condition and environmental characteristics (e.g. temp or salinity) Live birth and parental care Reproduction
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Maternal Care
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Stock-recruitment relationships Based on parental condition and environmental characteristics (e.g. temp or salinity) Live birth and maternal care Young of year recruits no explicit larval phase (miss predator-prey switch unless use plankton-based recruitment) Explicit larvae (advection or connectivity matrices) Reproduction
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Forced distributions Movement
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Forced (seasonal) distributions Density or forage dependent Sedentary Mixed Seasonal migrations must intersect with prey or starve spawn near rearing habitat or juveniles eaten Movement
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Forced (seasonal) distributions Density or forage dependent Sedentary Mixed Seasonal migrations must intersect with prey or starve spawn near rearing habitat or juveniles eaten Include if needed to represent ecology of interest vertical (access prey, benthopelagic coupling), seasonal (within model), migration (out of domain) Movement
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Non-zero values = commitment interaction that seems unimportant may become critical Connections can have non-symmetric impacts Use local (cogener) data preferentially Size-relationships predator-prey are consistent across systems Stomach content problems (soft bodies digest rapidly, patchy data, too few links can impact predictions) Isotopes Diets
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Diet Time Series
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e.g. seabirds (ontogeny, seasonal migrations) Quillfeldt et al 2010 Diet & Migration
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Bowhead whales – Northern Pacific Hobson et al 2010 Diet & Migration
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Ontogenetic shifts Flexible in space and time Model vs Obs
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Modelling theory System dynamics Impacts of perturbation Form of effective management vision statements vs realised outcomes effective monitoring ecosystem-based management multiple use management Questions tackled
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Atlantis – What, How, Why small pelagics squid zooplankton baleen whales birds pelagic sharks toothed whales pelagic fish demersal fish demersal sharks infauna macrophytes filter feeders zoobenthos detritus jellies phytoplankton 1910
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Community Structure
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Atlantis – What, How, Why 1910
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Atlantis – What, How, Why 2000
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Primary Producers ZooplanktonJelliesSquidBenthos Forage Fish Demersal FishTop Predators 2 -6 Index of effect size Temperature + Acidification Griffiths et al (in review) Antagonistic interaction Synergistic interaction All human pressures together Interacting Stressors
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Audzjionyte et al (in review) > 20% fishing mortality per year = selecting for smaller fish FECUNDITY 10-50% 50-90% Evolution
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Audzjionyte et al (in review) Mortality implications
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Evolution Audzjionyte et al (in review) Biomass implications Predator-prey implications Distribution implications
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Possible, but heterogeneity hard… better to use ABM Behaviour
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Thank you
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