6.3. Fishery Reserve
111
J = .2 2
Ki[Region] = 20000
Mi[Region] = .8
N = ARRAYSUM(Ni [ *])
N_DOT = ARRAYSUM(Ni_DOT [*])
P = 2.9
RAND [P12] = RANDOM( O,l , l)
RAND [P13] = RANDOM ( 0 ,1 , 2 )
RAND [P14] = RANDOM( 0,1, 3)
RAND [P21]
RANDOM(0 ,1, 4)
RAND[P23] = RANDOM(0 ,1 ,5)
RAND [P24] = RANDOM (0 , 1,6)
RAND[P31] = RANDOM(0,1,7 )
RAND[P32] = RANDOM(O,l,8)
RAND[P34] = RANDOM(0 ,1,9)
RAND[P41] = RANDOM(O,l,lO)
RAND[P42] = RANDOM(O,l ,ll)
RAND[P43] = RANDOM(O ,l, 1 2)
RAND_Nl = RAND[P1 2] +RAND[P13]+RAND[P14]
RAND_N2 = RAND [P21]+RAND[P23]+RAND[P24]
RAND_N3 = RAND[P31]+RAND[P32]+RAND[P34]
RAND_N4 = RAND[P41 ]+RAND[P42]+RAND[P43]
Ri [Region] = . 6
TOTAL_M = ARRAYSUM (M[ * ] )
V = .00006
6.3. Fishery Reserve
What are the effects on population size and effort if we close part of an
area to fishing? For simplicity, assume that we restrict fishing to only take
place in Regions 1, 2, and 3. No effort gets allocated to Region 4, and all effort that would have been used in Region 4 will be redistributed to the
other regions . To calculate effort-redistribution in the presence of a reserve ,
we need to change our model as shown in Figure 6.13. We compute the
population size outside the reserve (N minus N) , use that population size
to determine the population densities D, outside the reserve , set D 4 =0, and
then calculate E,=
analogous to the way we have done before.
Set M j = 0 for all four regions, choose ALPHA = .8, and leave all the
other parameters and initial conditions as before . Make an educated gues s,
and then run the model. Do the results coincide with your expectations ? If
not , why not? In Figure 6.14 are the results for our model run. The reserve
111
J = .2 2
Ki[Region] = 20000
Mi[Region] = .8
N = ARRAYSUM(Ni [ *])
N_DOT = ARRAYSUM(Ni_DOT [*])
P = 2.9
RAND [P12] = RANDOM( O,l , l)
RAND [P13] = RANDOM ( 0 ,1 , 2 )
RAND [P14] = RANDOM( 0,1, 3)
RAND [P21]
RANDOM(0 ,1, 4)
RAND[P23] = RANDOM(0 ,1 ,5)
RAND [P24] = RANDOM (0 , 1,6)
RAND[P31] = RANDOM(0,1,7 )
RAND[P32] = RANDOM(O,l,8)
RAND[P34] = RANDOM(0 ,1,9)
RAND[P41] = RANDOM(O,l,lO)
RAND[P42] = RANDOM(O,l ,ll)
RAND[P43] = RANDOM(O ,l, 1 2)
RAND_Nl = RAND[P1 2] +RAND[P13]+RAND[P14]
RAND_N2 = RAND [P21]+RAND[P23]+RAND[P24]
RAND_N3 = RAND[P31]+RAND[P32]+RAND[P34]
RAND_N4 = RAND[P41 ]+RAND[P42]+RAND[P43]
Ri [Region] = . 6
TOTAL_M = ARRAYSUM (M[ * ] )
V = .00006
6.3. Fishery Reserve
What are the effects on population size and effort if we close part of an
area to fishing? For simplicity, assume that we restrict fishing to only take
place in Regions 1, 2, and 3. No effort gets allocated to Region 4, and all effort that would have been used in Region 4 will be redistributed to the
other regions . To calculate effort-redistribution in the presence of a reserve ,
we need to change our model as shown in Figure 6.13. We compute the
population size outside the reserve (N minus N) , use that population size
to determine the population densities D, outside the reserve , set D 4 =0, and
then calculate E,=
analogous to the way we have done before.
Set M j = 0 for all four regions, choose ALPHA = .8, and leave all the
other parameters and initial conditions as before . Make an educated gues s,
and then run the model. Do the results coincide with your expectations ? If
not , why not? In Figure 6.14 are the results for our model run. The reserve