INFLOWS:
GR ¼ PULSE(SMALL_PRED,8,104) {Individuals per Week}
OUTFLOWS:
PRED_DEATH_RATE ¼ IF PREDATOR <1 THEN 1 ELSE (PRED_DEATH * REGULATION_STRENGTH) * PREDATOR {Individuals per Week}
SMALL_PRED(t) ¼ SMALL_PRED(t À dt) + (JUV_MAT À GR À
SM_PRED_DEATH) * dt
INIT SMALL_PRED ¼ 100 {Individuals}
INFLOWS:
JUV_MAT ¼ PULSE(JUV_PRED,8,52) {Individuals per Week}
OUTFLOWS:
GR ¼ PULSE(SMALL_PRED,8,104) {Individuals per Week}
SM_PRED_DEATH ¼ (PREDATOR_GROW * REGULATION_STRENGTH)
* SMALL_PRED {Individuals per Week}
YEARLING(t) ¼ YEARLING(t À dt) + (LATE_JUV_GROW À
YEARLING_GROW À YEAR_DIE) * dt
INIT YEARLING ¼ 60 {Individuals}
INFLOWS:
LATE_JUV_GROW ¼ PULSE(LATE_JUV,9,52) {Individuals per Week}
OUTFLOWS:
YEARLING_GROW ¼ PULSE(YEARLING,7,52) {Individuals per Week}
YEAR_DIE ¼ IF YEARLING <1 THEN 0 ELSE (YEARLING * SIZE_RATE_4)
+WINTERKILL_4 {Individuals per Week}
ZOOP(t) ¼ ZOOP(t À dt) + (ZOOP_GROWTH À CONSUMPTION_SHAD) * dt
INIT ZOOP ¼ 1000 {Units of Biomass}
INFLOWS:
ZOOP_GROWTH ¼ ZOOP * GROWTH_ZOOP {Units of Biomass per Week}
OUTFLOWS:
CONSUMPTION_SHAD ¼ IF ZOOP <1 THEN 0 ELSE (ZOOP * CONSUMPTION_RATE_SHAD) {Units of Biomass per Week}
ADULT_GROWTH ¼ ADULT/ZOOP * .0009
BIOMANIPULATION ¼ PULSE(DEGREE,50,TIMING) {Individuals per Week}
CONSUMPTION_RATE_SHAD ¼ GRAPH(SHAD_BIOMASS)
(0.00, 0.00), (100, 0.065), (200, 0.155), (300, 0.25), (400, 0.345), (500, 0.46),
(600, 0.54), (700, 0.66), (800, 0.775), (900, 0.895), (1000, 1.00)
CONSUMPTION_RATE_ZOOP ¼ GRAPH(ZOOP )
(0.00, 0.01), (10.0, 0.34), (20.0, 0.52), (30.0, 0.625), (40.0, 0.73), (50.0, 0.805),
(60.0, 0.865), (70.0, 0.905), (80.0, 0.94), (90.0, 0.98), (100, 1.00)
DEGREE ¼ 0 {Week}
EARLY_JUV_GROWTH ¼ GRAPH((EARLY_JUV+LARVAL)/ZOOP)
(0.00, 1.00), (100, 1.00), (200, 1.00), (300, 0.99), (400, 0.965), (500, 0.705),
(600, 0.435), (700, 0.34), (800, 0.31), (900, 0.3), (1000, 0.3)
EGG_SURVIVAL ¼ ABS(RANDOM(SURVIVAL,.009))
GROWTH_ALGAE ¼ GRAPH(ALGAE)
(0.00, 14.8), (1e+07, 12.0), (2e+07, 9.30), (3e+07, 7.95), (4e+07, 6.83), (5e+07,
6.45), (6e+07, 6.22), (7e+07, 6.22), (8e+07, 6.22), (9e+07, 6.08), (1e+08, 6.08)
37.2 Gizzard Shad Model Equations
345