TEMP_LAG(t) ¼ TEMP_LAG(t À dt) + (TEMP_RATE À LAG_RATE) * dt
INIT TEMP_LAG ¼ 0 {Degrees C}
INFLOWS:
TEMP_RATE ¼ AIR_TEMP {Degrees C per Time Period}
OUTFLOWS:
LAG_RATE ¼ TEMP_LAG/3 {Degrees C per Time Period}
A ¼ .11E-12 {from fig 3À11, page 3À27, part 3}
ACTIV_FAC ¼ TC/(1.06 * C)+1
ACTUAL_INGEST ¼ IF NUMBER > 0 THEN GRAZE_MORT * FCC1/
DRY_WETPLT/NUMBER ELSE 0 {Converting the actually allowed ingestion
back to Wet Standard Calories per Fish-Week from Dry Vegetation Grams per
Week.}
AIR_TEMP ¼ À2.8474-1.025 * WEEK+.2114 * (WEEK)^2-.0066 * (WEEK)^3+5.548E
À5 * (WEEK)^4 + NORMAL(1,3) {Degrees C}
ASSIMILATION ¼ IF (WATER_TEMP > 1) AND (G_SIZE > 1) THEN À.026.058 * LN(G_SIZE) + .213 * LN(WATER_TEMP) ELSE 0 {see eqn 8, page
859, Wiley & Wike, AFS, 1986.}
AVG_AGE ¼ IF TIME >¼ TIME_2 THEN (NO_AT_T2 * TIME_2/52)/
(NO_AT_T2 + NUM_2) + (TIME - TIME_2)/52 ELSE TIME/52
B ¼ 3.45
BWPD ¼ IF G_SIZE <15000 THEN 0.52 ELSE .21 {Average consumption rate
for Elodea; Grams Wet Vegetation per Gram Fresh Fish–Day}
C ¼ IF DESIRED_INGEST > INGESTION THEN 2 ELSE 1 {Reduces assimilation rate during starvation}
DESIRED_GRAZE ¼ NUMBER * DESIRED_INGEST * DRY_WETPLT/FCC1
{Dry Vegetation Grams per Week. Conversion: from Standard Calories by /
FCC1; from Wet Grams to Dry Grams by * DRY WETPLT}
DESIRED_INGEST ¼ 7 * BWPD * G_SIZE * TC * PLOIDY * FCC1 {Regular Calories per Fish–Week}
DRY_WETPLT ¼ .24 {This is the dry to wet weight ratio for Elodea.}
FCC1 ¼ IF (G_SIZE < 30) AND (G_SIZE >¼ 0) THEN 500 ELSE FCC2
{Calories per gram of wet weight of Elodea c.}
FCC2 ¼ IF (G_SIZE >¼ 30) AND (G_SIZE < 100) THEN 1000 ELSE FCC3
{Calories per gram of wet weight of Elodea c.}
FCC3 ¼ IF G_SIZE >¼ 100 THEN 430 ELSE 0 {430 Calories per gram of wet
weight of Elodea c.}
FSIZECAL_2 ¼ 827.18 * F_SIZE_G_2^1.0968 + .0115 * F_SIZE_G_2^2.1936
F_SIZE_CAL_1 ¼ 827.18 * F_SIZE_G_1^1.0968 + .0115 * F_SIZE_G_1^2.1936
{See Ref. under FSizeCal_2; eqn is multiplied by FSize_g_1 to get total Standard Calories per Fish}
F_SIZE_G_1 ¼ 200 {Grams fresh weight, per fish. This variable is set by the user.}
F_SIZE_G_2 ¼ 200 {The size of the average fish in the second pulse, in g fresh
weight. This variable is set by the user.}
G ¼ .125 {Instantaneous growth rate of Elodea c., Grams per Gram-Day}
36.2 Grass Carp Model Equations
323
INIT TEMP_LAG ¼ 0 {Degrees C}
INFLOWS:
TEMP_RATE ¼ AIR_TEMP {Degrees C per Time Period}
OUTFLOWS:
LAG_RATE ¼ TEMP_LAG/3 {Degrees C per Time Period}
A ¼ .11E-12 {from fig 3À11, page 3À27, part 3}
ACTIV_FAC ¼ TC/(1.06 * C)+1
ACTUAL_INGEST ¼ IF NUMBER > 0 THEN GRAZE_MORT * FCC1/
DRY_WETPLT/NUMBER ELSE 0 {Converting the actually allowed ingestion
back to Wet Standard Calories per Fish-Week from Dry Vegetation Grams per
Week.}
AIR_TEMP ¼ À2.8474-1.025 * WEEK+.2114 * (WEEK)^2-.0066 * (WEEK)^3+5.548E
À5 * (WEEK)^4 + NORMAL(1,3) {Degrees C}
ASSIMILATION ¼ IF (WATER_TEMP > 1) AND (G_SIZE > 1) THEN À.026.058 * LN(G_SIZE) + .213 * LN(WATER_TEMP) ELSE 0 {see eqn 8, page
859, Wiley & Wike, AFS, 1986.}
AVG_AGE ¼ IF TIME >¼ TIME_2 THEN (NO_AT_T2 * TIME_2/52)/
(NO_AT_T2 + NUM_2) + (TIME - TIME_2)/52 ELSE TIME/52
B ¼ 3.45
BWPD ¼ IF G_SIZE <15000 THEN 0.52 ELSE .21 {Average consumption rate
for Elodea; Grams Wet Vegetation per Gram Fresh Fish–Day}
C ¼ IF DESIRED_INGEST > INGESTION THEN 2 ELSE 1 {Reduces assimilation rate during starvation}
DESIRED_GRAZE ¼ NUMBER * DESIRED_INGEST * DRY_WETPLT/FCC1
{Dry Vegetation Grams per Week. Conversion: from Standard Calories by /
FCC1; from Wet Grams to Dry Grams by * DRY WETPLT}
DESIRED_INGEST ¼ 7 * BWPD * G_SIZE * TC * PLOIDY * FCC1 {Regular Calories per Fish–Week}
DRY_WETPLT ¼ .24 {This is the dry to wet weight ratio for Elodea.}
FCC1 ¼ IF (G_SIZE < 30) AND (G_SIZE >¼ 0) THEN 500 ELSE FCC2
{Calories per gram of wet weight of Elodea c.}
FCC2 ¼ IF (G_SIZE >¼ 30) AND (G_SIZE < 100) THEN 1000 ELSE FCC3
{Calories per gram of wet weight of Elodea c.}
FCC3 ¼ IF G_SIZE >¼ 100 THEN 430 ELSE 0 {430 Calories per gram of wet
weight of Elodea c.}
FSIZECAL_2 ¼ 827.18 * F_SIZE_G_2^1.0968 + .0115 * F_SIZE_G_2^2.1936
F_SIZE_CAL_1 ¼ 827.18 * F_SIZE_G_1^1.0968 + .0115 * F_SIZE_G_1^2.1936
{See Ref. under FSizeCal_2; eqn is multiplied by FSize_g_1 to get total Standard Calories per Fish}
F_SIZE_G_1 ¼ 200 {Grams fresh weight, per fish. This variable is set by the user.}
F_SIZE_G_2 ¼ 200 {The size of the average fish in the second pulse, in g fresh
weight. This variable is set by the user.}
G ¼ .125 {Instantaneous growth rate of Elodea c., Grams per Gram-Day}
36.2 Grass Carp Model Equations
323