Changes between Version 2 and Version 3 of EwEugEditMultiStanzaGroups


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Timestamp:
2010-11-23 00:44:21 (8 years ago)
Author:
shermanl
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  • EwEugEditMultiStanzaGroups

    v2 v3  
    11== 6.3 Edit multi-stanza groups == 
    2 Multi-stanza groups are defined using the [wiki:EwEugEditGroups Edit groups] form, accessible from the ''Ecopath menu'' on the ''Menu bar''. Multi-stanza 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 multi-stanza groups as this makes their dynamics more realistic, provides insights on stock-recruitment relationships, and allows consideration of stanza-specific habitat use. See the introductory material on [wiki:EwEugRepresentationOfMultiStanza multi-stanza 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. 
     2Multi-stanza groups are defined using the [wiki:EwEugEditGroups Edit groups] form, accessible from the ''Ecopath menu'' on the ''Menu bar''. Multi-stanza groups represent life history stages or stanzas for species that have complex trophic ontogeny. Mortality rates (''M,,0,,'', 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 multi-stanza groups as this makes their dynamics more realistic, provides insights on stock-recruitment relationships, and allows consideration of stanza-specific habitat use. See the introductory material on [EwEugRepresentationOfMultiStanzaLifeHistoriesInEcopathEcoSimAndEcospace multi-stanza groups] and [EwEugUsingEcosimToStudyCompensationInRecruitmentRelationships 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. 
    33 
    44Once you have defined a multi-stanza group(s) you must go to the ''Edit multi-stanza groups'' form to set the parameters needed to calculate the biomass and numbers in each age category. To open the ''Edit multi-stanza groups'' form, choose the ''Edit multi-stanza groups...'' option on the'' Ecopath menu''. Features of the ''Edit multi-stanza groups'' form are shown in Figure 6.1. 
    55 
    6 You must enter baseline estimates of total mortality rate ''Z'' (i.e., ''P/B'') and diet composition for each stanza, and biomass and consumption (''Q/B'') for one “leading” stanza only (the oldest stanza). Biomass and consumption are then computed for the other stanzas, assuming a stable age distribution. 
     6You must enter baseline estimates of total mortality rate ''Z'' (i.e., ''P/B'') and diet composition for each stanza, and biomass and consumption (''Q/B'') for one "leading" stanza only (the oldest stanza). Biomass and consumption are then computed for the other stanzas, assuming a stable age distribution. 
    77 
    88[[Image(wiki:EwEugImages:EditMultiStanza_sc.bmp)]] 
     
    2020'''Recruitment power''' 
    2121 
    22 This parameter is used by Ecosim and sets the degree of density dependence in juvenile survival for juveniles outside the modelled area. Set a low value, (e.g., 0.1-0.5) for this parameter if the juveniles for a group spend some time ‘outside’ the system in a nursery area where they are subject to density-dependent juvenile mortality rate, (e.g., juvenile Pacific salmon abundance may be limited by freshwater nursery habitat, so that numbers recruiting to a coastal oceanic area can be practically independent of adult abundance in the oceanic area, especially if juvenile production is ‘enhanced’ by hatchery systems). 
     22This parameter is used by Ecosim and sets the degree of density dependence in juvenile survival for juveniles outside the modelled area. Set a low value, (e.g., 0.1-0.5) for this parameter if the juveniles for a group spend some time 'outside' the system in a nursery area where they are subject to density-dependent juvenile mortality rate, (e.g., juvenile Pacific salmon abundance may be limited by freshwater nursery habitat, so that numbers recruiting to a coastal oceanic area can be practically independent of adult abundance in the oceanic area, especially if juvenile production is 'enhanced' by hatchery systems). 
    2323 
    24 Note that you should not need to change other basic parameters defining trophic ontogeny for split groups. When it is the very early juvenile stage that is spent in some rearing habitat outside your modelled area (e.g. a stream or coastal lagoon), you may model the effect of limiting factors within that rearing habitat just by adjusting the recruitment power parameter, without bothering to account factors such as  ‘Import’ of food to the juvenile biomass while juveniles are in the rearing area (cumulative effect of such trophic development are automatically calculated when scaling the juvenile body sizes within Ecosim based on Ecopath juvenile pool biomass).  You can also use a low recruitment power parameter to make juvenile recruitment ‘flat’ with respect to modelled adult biomass due to recruitment of juveniles from some adult population ‘egg source’ outside the modelled area. 
     24Note that you should not need to change other basic parameters defining trophic ontogeny for split groups. When it is the very early juvenile stage that is spent in some rearing habitat outside your modelled area (e.g. a stream or coastal lagoon), you may model the effect of limiting factors within that rearing habitat just by adjusting the recruitment power parameter, without bothering to account factors such as  'Import' of food to the juvenile biomass while juveniles are in the rearing area (cumulative effect of such trophic development are automatically calculated when scaling the juvenile body sizes within Ecosim based on Ecopath juvenile pool biomass).  You can also use a low recruitment power parameter to make juvenile recruitment 'flat' with respect to modelled adult biomass due to recruitment of juveniles from some adult population 'egg source' outside the modelled area. 
    2525 
    2626'''Relative biomass accumulation rate (BA/B)''' 
    2727 
    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 Multi-stanza groups]). See [wiki:EwEugOtherProduction Other production] for notes about estimating the relative biomass accumulation rate. 
     28The ''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 [EwEugRepresentationOfMultiStanzaLifeHistoriesInEcopathEcoSimAndEcospace Multi-stanza groups]). See [wiki:EwEugOtherProduction Other production] for notes about estimating the relative biomass accumulation rate. 
    2929 
    3030'''Weight at maturity/W_infinity''' 
     
    5252'''Biomass''' 
    5353 
    54 You must enter estimated absolute biomass (in appropriate units) for one “leading” stanza (i.e., the oldest stanza). 
     54You must enter estimated absolute biomass (in appropriate units) for one "leading" stanza (i.e., the oldest stanza). 
    5555 
    56 '''Z (Production/Biomass)''' 
     56'''Z (Production / Biomass)''' 
    5757 
    5858You must enter estimated total mortality rates for each stanza. A single-species age-structured model can be used to help estimate these parameters. 
    5959 
    60 '''Consumption/Biomass''' 
     60'''Consumption / Biomass''' 
    6161 
    62 You must enter estimated consumption/biomass (''Q/B'') for one “leading” stanza (i.e., the oldest stanza). 
     62You must enter estimated consumption/biomass (''Q/B'') for one "leading" stanza (i.e., the oldest stanza). 
    6363 
    6464A plot showing numbers at age, biomass age and weight at age is shown at the left of the form. This plot can be used to guide you in setting parameters for the group. To update the plot after changing parameters, click the ''Calculate'' button. To close the form and implement changes, click the ''OK'' button. To exit without implementing any changes, click the ''Cance''l button.