12.2. Model Structure
235
1 0 . 160
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I
Month
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12.00
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1:
as
1 0 . 000
...........
1.000
o
based on both test size and the relative density at which urchins can be
found. Relative density is calculated by dividing the biomass of urchins in a
cohort by the total biomass of all cohorts.
Urchins in this model do not have a constant growth rate to move them
through the cohorts; rather , the time it take s to grow depends on the size of
RecruitRate
die2
tto 2
Urchin 1115
dead1
Biomass 30plus