Modelling Vertebrates Beth Fulton 2012

End to End Model

Difference equation time step assumed (agreed upon) Differential equation instantaneous (or really tiny time slices) D.E.

Life history ReprodGrowthMetab.MoveAgingMortality

Biomass Aggregate Biomass Recruitment, Migration & Growth Mortality & metabolism e.g. Ecopath

Numbers Abundance Recruitment & Migration Mortality

Age Structure Aging & Growth Recruitment Mortality Stock assessments

Can be simple (just age structure) Can be complex (spatial, genetic stocks etc) Age Structure

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

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

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

Stock-recruitment relationships Adults Recruits Beverton Holt Fixed # offspring / adult Ricker Reproduction Others = lognormal, plankton-based…

Stock-recruitment relationships Based on parental condition and environmental characteristics (e.g. temp or salinity) Live birth and parental care Reproduction

Maternal Care

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

Forced distributions Movement

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

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

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

Diet Time Series

e.g. seabirds (ontogeny, seasonal migrations) Quillfeldt et al 2010 Diet & Migration

Bowhead whales – Northern Pacific Hobson et al 2010 Diet & Migration

Ontogenetic shifts Flexible in space and time Model vs Obs

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

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

Community Structure

Atlantis – What, How, Why 1910

Atlantis – What, How, Why 2000

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

Audzjionyte et al (in review) > 20% fishing mortality per year = selecting for smaller fish FECUNDITY 10-50% 50-90% Evolution

Audzjionyte et al (in review) Mortality implications

Evolution Audzjionyte et al (in review) Biomass implications Predator-prey implications Distribution implications

Possible, but heterogeneity hard… better to use ABM Behaviour

Thank you