410
18. The Global Shrimp Market
Cumulative_lbs_other_species(t) =
Cumulative_lbs_other_species(t-dt) +
(monthly_impact_on_other_species) * dt
INIT Cumulative_lbs_other_species = °
INFLOWS:
monthly_impact_on_other_species
bycatch_fisheries+other_species_in_fishmeal
Good_Practice(t) = Good_Practice(t-dt) +
(gaining_good-ponds + becoming_goodabandoning_good-ponds-becoming_bad) * dt
INIT Good_Practice
Hectares_of_Ponds*.l
INFLOWS:
gaining_good-ponds
MIN((finishing__development*fraction_good_new_developme
nt)+additional_good-practice , (finishing__development))
becoming_good = MAX(ha_converted_to_good ,O)
OUTFLOWS:
abandoning_good-ponds =
Good_Practice /time_to_abandon_good
becoming_bad = °
additional_good-practice =
annual_good-practice_incentives /cost_of_good-practice_h
a
annual_good-practice_incentives = 1
bycatch_fisheries =
catching*lbs_bycatch-per_lb_shrimp_fisheries
coastal_effluents =
Hectares_of_Ponds*effluents_discharged\pond
cost_of_good-practice_ha = 60000
fraction_good_new_development =
(good-practice_switch*effect_of_stock_loss_on_good-pr a c
tice)+((1-good-practice_switchl* .02)
good-practice_switch = °
ha_converted_to_good = additional_good-practicefinishing__development
lbs_bycatch-per_lb_shrimp_aquaculture = 5
lbs_bycatch-per_lb_shrimp_fisheries = 5
other_species_in_fishmeal =
Shrimp_in_Ponds* lbs_bycatch-per_lb_shrimp_aquaculture
percent_good =
Good_Practice /(Bad_Practice+Good_Practice)