Changes between Version 8 and Version 9 of EwEugMortalityForaPreyIsConsumptionForaPredator


Ignore:
Timestamp:
2010-11-21 22:22:51 (9 years ago)
Author:
shermanl
Comment:

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  • EwEugMortalityForaPreyIsConsumptionForaPredator

    v8 v9  
    5959For parameterization Ecopath sets up a system with (at least in principle) as many linear equations as there are groups in a system, and it solves the set for one of the following parameters for each group: 
    6060 
    61   Biomass;Production/biomass ratio;Consumption/biomass ratio; orEcotrophic efficiency. 
     61 * Biomass; 
     62 * Production/biomass ratio; 
     63 * Consumption/biomass ratio; or 
     64 * Ecotrophic efficiency. 
    6265 
    6366If, and only if, all four of these parameters are entered, the program will prompt you during basic parameterization whether to estimate the biomass accumulation, or, alternatively, to estimate the net migration rate. If a positive response is given, the program will use all the four basic parameters and it will establish mass-balance by calculating one of the two other parameters. If only three of the basic parameters are entered the following parameters must be entered for all groups: 
    6467 
    65   Catch rate;Net migration rate;Biomass accumulation rate;Assimilation rate; andDiet compositions. 
     68 * Catch rate; 
     69 * Net migration rate; 
     70 * Biomass accumulation rate; 
     71 * Assimilation rate; and 
     72 * Diet compositions. 
    6673 
    6774It was indicated above that Ecopath does not rely on solving a full set of linear equations, i.e., there may be less equations than there are groups in the system. This is due to a number of algorithms included in the parameterization routine that will try to estimate iteratively as many 'missing' parameters as possible before setting up the set of linear equations. The following loop is carried out until no additional parameters can be estimated.