Changes between Version 1 and Version 2 of EwEugEditMultiStanzaGroups
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 20100205 15:13:37 (13 years ago)
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EwEugEditMultiStanzaGroups
v1 v2 1 1 == 6.3 Edit multistanza groups == 2 Multistanza groups are defined using the [ [Edit groups.htmEdit groups]] form, accessible from the ''Ecopath menu'' on the ''Menu bar''. Multistanza groups represent life history stages or stanzas for species that have complex trophic ontogeny. Mortality rates (''M0'', predation, fishing) and diet composition are assumed to be similar for individuals within each stanza (e.g., larvae having high mortality and feeding on zooplankton, juveniles having lower mortality and feeding on benthic insects, adults having still lower mortality and feeding on fish). For Ecosim and Ecospace it is advised to split top predators into multistanza groups as this makes their dynamics more realistic, provides insights on stockrecruitment relationships, and allows consideration of stanzaspecific habitat use. See the introductory material on [[Representation of multi stanza.htmmultistanza groups]] and [[Using Ecosim to study compensation.htmUsing Ecosim to study compensation in recruitment relationships]] (Chapters 2 and 3 of the EwE6 User Guide) for more information on how these groups are modelled in Ecopath, Ecosim and Ecospace.2 Multistanza groups are defined using the [wiki:EwEugEditGroups Edit groups] form, accessible from the ''Ecopath menu'' on the ''Menu bar''. Multistanza groups represent life history stages or stanzas for species that have complex trophic ontogeny. Mortality rates (''M0'', predation, fishing) and diet composition are assumed to be similar for individuals within each stanza (e.g., larvae having high mortality and feeding on zooplankton, juveniles having lower mortality and feeding on benthic insects, adults having still lower mortality and feeding on fish). For Ecosim and Ecospace it is advised to split top predators into multistanza groups as this makes their dynamics more realistic, provides insights on stockrecruitment relationships, and allows consideration of stanzaspecific habitat use. See the introductory material on [wiki:EwEugRepresentationOfMultiStanza multistanza groups] and [wiki:EwEugUsingEcosimToStudyCompensation Using Ecosim to study compensation in recruitment relationships] (Chapters 2 and 3 of the EwE6 User Guide) for more information on how these groups are modelled in Ecopath, Ecosim and Ecospace. 3 3 4 4 Once you have defined a multistanza group(s) you must go to the ''Edit multistanza groups'' form to set the parameters needed to calculate the biomass and numbers in each age category. To open the ''Edit multistanza groups'' form, choose the ''Edit multistanza groups...'' option on the'' Ecopath menu''. Features of the ''Edit multistanza groups'' form are shown in Figure 6.1. … … 26 26 '''Relative biomass accumulation rate (BA/B)''' 27 27 28 The ''BA/B'' term represents effect on the numbers at age of the population growth rate (e.g. the cohort born one year ago should be smaller by the factor ../Resources/Images/0800001E.png than the cohort born “''a''” years ago (see [[Representation of multi stanza.htmMultistanza groups]]). See [[Other production.htmOther production]] for notes about estimating the relative biomass accumulation rate.28 The ''BA/B'' term represents effect on the numbers at age of the population growth rate (e.g. the cohort born one year ago should be smaller by the factor [[Image(wiki:EwEugImages:0800001E.png)]] than the cohort born “''a''” years ago (see [wiki:EwEugRepresentationOfMultiStanza Multistanza groups]). See [wiki:EwEugOtherProduction Other production] for notes about estimating the relative biomass accumulation rate. 29 29 30 30 '''Weight at maturity/W_infinity''' … … 34 34 '''Forcing function number for hatchery stocking''' 35 35 36 Multistanza populations can be designated as hatchery populations (see [ [Hatchery populations in Ecosim.htmHatchery populations in Ecosim]]), and hatchery production can be varied over time in Ecosim using time forcing functions. To turn off natural reproduction select the hatchery forcing function from the pulldown menu in the ''Forcing function number for hatchery stocking'' box.36 Multistanza populations can be designated as hatchery populations (see [wiki:EwEugHatcheryPopulationsInEcosim Hatchery populations in Ecosim]), and hatchery production can be varied over time in Ecosim using time forcing functions. To turn off natural reproduction select the hatchery forcing function from the pulldown menu in the ''Forcing function number for hatchery stocking'' box. 37 37 38 Note, you must already have a forcing time series loaded in Ecosim (see [ [Time series.htmTime series]] and [[Forcing function.htmForcing function]]). Note that forcing functions to represent historical changes in stocking rates can be entered via the same csv files as used to set up historical fishing and model fitting scenarios. Enter stocking rates as values relative to the stocking rate of 1.0 assumed for the Ecopath base year.38 Note, you must already have a forcing time series loaded in Ecosim (see [wiki:EwEugTimeSeries Time series] and [wiki:EwEugForcingFunction Forcing function]). Note that forcing functions to represent historical changes in stocking rates can be entered via the same csv files as used to set up historical fishing and model fitting scenarios. Enter stocking rates as values relative to the stocking rate of 1.0 assumed for the Ecopath base year. 39 39 40 40 At each simulation time step, the base recruitment for the population (calculated from Ecopath input parameters) will be multiplied by the current time value for the designated forcing function.