96
5. Impact of Fishing Pressure on Mean Length of Fish
BIRTH_RATE_1_2[LONG]*(2/3) *(1RAND_1_2[LONG])*YEAR_1_2[LONG]+
BIRTH_RATE_2_3[LONG]*(2/3)*(1RAND_2_3[LONG])*YEAR_2_3[LONG]
BIRTHS [LONG] =
BIRTH_RATE_1_2 [LONG] *RAND_1_2 [LONG] *YEAR_1_2 [LONG] +
BIRTH_RATE_2_3 [LONG] *RAND_2_3 [LONG] *YEAR_2_3[LONG] +
BIRTH_RATE_1_2[SHORT]*(1 /3)*(1RAND_1_2[SHORT])*YEAR_1_2[SHORT]+
BIRTH_RATE_2_3[SHORT]*(1 /3)*(1RAND_2_3[SHORT])*YEAR_2_3[SHORT]+
BIRTH_RATE_1_2[MED] *.5* (1-RAND_1_2[MED])*YEAR_1_2[MED]+
BIRTH_RATE_2_3[MED]*.5*(1-RAND_2_3[MED])*YEAR_2_3[MED]
OUTFLOWS:
AGE_O_1[LENGTH] = (1TOTAL_MORTALITY_O_1[LENGTH])*YEAR_O_1[LENGTH]
DEATHS_O_1[LENGTH] =
TOTAL_MORTALITY_O_1[LENGTH] *YEAR_O_1 [LENGTH]
YEAR_1_2[LENGTH] (t) = YEAR_1_2[LENGTH] (t-dt) +
(AGE_O_1[LENGTH]-AGE_1_2[LENGTH]-DEATHS_1_2[LENGTH]) *
dt
INIT YEAR_1_2[LENGTH] = 76
INFLOWS:
AGE_O_1[LENGTH] = (1TOTAL_MORTALITY_O_1[LENGTH])*YEAR_O_1[LENGTH]
OUTFLOWS:
AGE_1_2[LENGTH] = (1TOTAL_MORTALITY_1_2[LENGTH])*YEAR_1_2[LENGTH]
DEATHS_1_2[LENGTH] =
TOTAL_MORTALITY_1_2[LENGTH] *YEAR_1_2 [LENGTH]
YEAR_2_3[LENGTH] (t) = YEAR_2_3[LENGTH] (t-dt) +
(AGE_1_2[LENGTH]-DEATHS_2_3[LENGTH]) * dt
INIT YEAR_2_3[LENGTH] = 67
INFLOWS:
= (1TOTAL_MORTALITY_1_2[LENGTH])*YEAR_1_2[LENGTH]
OUTFLOWS:
DEATHS_2_3[LENGTH] = YEAR_2_3[LENGTH]
BIRTH_RATE_1_2[LENGTH] = .6
BIRTH_RATE_2_3[LENGTH] = .8
FISHING_MORTALITY [SHORT] = °
FISHING_MORTALITY [MED] = .2