FRAC_PEAK_LEFT(t) ¼ FRAC_PEAK_LEFT(t À dt) + (PEAK_RATE) * dt
INIT FRAC_PEAK_LEFT ¼ 0
INFLOWS:
PEAK_RATE ¼ IF (F1 > PSG) AND (F1 > F2) AND (F1 > 50000) THEN
F1/4250000 ELSE 0
NO_AT_T2(t) ¼ NO_AT_T2(t À dt) + (NT2) * dt
INIT NO_AT_T2 ¼ 0 {This section calculates the average age of the fish in years.
It averages the fish of the second pulse with the age of the remaining fish from
the first pulse.}
INFLOWS:
NT2 ¼ IF TIME ¼ TIME_2 THEN NUMBER ELSE 0
NUMBER(t) ¼ NUMBER(t À dt) + (STOCK_RATE À MORTALITY) * dt
INIT NUMBER ¼ 0
INFLOWS:
STOCK_RATE ¼
PULSE(NUM_1,TIME_1,1000) + PULSE(NUM_2,
TIME_2,1000) {These are the Pulse functions. They only work with Euler
integration and dt ¼1.00. See Specs Menu.}
OUTFLOWS:
MORTALITY ¼ PRED_MORT + WINTER_MORT + STARVE_MORT
PLANT_MAX(t) ¼ PLANT_MAX(t À dt) + (PLT_STOCK À FLOW_1) * dt
INIT PLANT_MAX ¼ 0
INFLOWS:
PLT_STOCK ¼ PLANT_STOCK_G {This section computes the total area under
the plant curve for the ten-year test run and then divides it by the total area under
the undisturbed (by grazing) curve of plant growth.}
OUTFLOWS:
FLOW_1 ¼ IF TIME ¼ 519 THEN PLANT_MAX/45300000 ELSE 0 {Divides
the cumulative area under the plant stock (Grams) vs. time curve by the area
under the standard curve (10 years), no variation in the avg. temp. curve}
PLANT_STOCK_G(t) ¼ PLANT_STOCK_G(t À dt) + (PLANT_GROWTH À
PLANT_MORT À GRAZE_MORT) * dt
INIT PLANT_STOCK_G ¼ 5000 {Grams Dry Weight per 1000 Square Meters.
To change veg. type, change variables: A, B, FCC3, G, PC, PCC, TEMP
SWITCHG, and DRY WETPLT}
INFLOWS:
PLANT_GROWTH ¼ IF PLANT_STOCK_G > 0 THEN 7 * TEMP_SWITCH_
G * G * PLANT_STOCK_G * (1-PLANT_STOCK_G/PCC) ELSE 0 {Grams dry
weight per 1000 Square Meters–Week}
OUTFLOWS:
PLANT_MORT ¼ IF P_MORT_TENAT >¼ PLANT_STOCK_G À 5000 THEN
(PLANT_STOCK_G À5000) ELSE P_MORT_TENAT
GRAZE_MORT ¼ IF DESIRED_GRAZE <¼ PLANT_STOCK_G À 5000
THEN DESIRED_GRAZE ELSE GRAZE_MORT_1 {Dry Weight Grams per
Week. A 5000 Gram/Square Meter-Week reserve is maintained.}
322
36 The Grass Carp