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Exercise 16
SMALL
MEDIUM
LARGE
VERY LARGE
EGGS··· .. ·
~ MATURATION WITH ATTENDANT MORTALITY
............. ~ EGG PRODUCTION
S
SURVIVORSHIP PER DAY FOR A SPECIFIC STAGE
o DAILY AGE GROUP (SIZE CLASSES)
Figure 16.1. Discrete time interval model pathways with assumed directions of survivorship
and mortality. Se = egg survivorship; Ss = small survivorship; Sm = medium survivorship; SI =
large survivorship; and Sv = very large survivorship per day.
with the assumptions made below. Then,
Number in the size
.
I
1
= [(survlVal rate) (number in size class at t or in egg class)]
c ass at t +
(number that
(number of survivors
advances to the + recruited in from
next size class)
smaller size class)
Biomass for size
(numbers in size class
(biomass of that
x
class at t + 1
at a given day)
size class)
Then the sum of all biomass of the different size classes = zooplankton biomass
on daYn.