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12. Kelp, Urchins, and Otters in the California Coastal Region
INFLOWS:
Kelp_Die_off
Standing_Kelp_Biomass*Die_off_Rate
{kg/mon t h }
OUTFLOWS :
Urch_eat_Drift = if Drift_Kelp_Biomass <
((Drift_Graze *Total_Urchins) /DT) then
Drift_Kelp_Biomass else
((Drift_Graze *Total_Urchins) /DT) {kg/month}
Drift_Kelp_Exits_System = 0 .9*Drift_Kelp_Biomass
{kg/mon t h }
Standing_Kelp_Biomass(t ) = Standing_Kelp_Biomass(t-dt)
+ (Biomass_Accumulation-Kelp_Die_off-Urch_eat_Stand) *
dt
INIT Standing_Kelp_Biomass = 1e6 {kg}
INFLOWS :
Biomass_Accumulation
Growth_Rate*Standing_Kelp_Biomass* (1(Standing_Kelp_Biomass /Carry_Cap»
OUTFLOWS:
{kg /month}
Kelp_Die_off = Standing_Kelp_Biomass *Die_off_Rate
{kg /month}
Urch_eat_Stand = ((1 -
Die_off_Rate ) *Standing_Kelp_Biomass ) * ((Total_Urchins *St
and_Graze) /DT ) {kg /m onth}
Carry_Cap = 22e6 {kg}
Die_off_Rate = 0. 166 {kg k e l p per kg k e l p per month}
Drift_Graze = 0.043 {kg}
Growth_Rate = 0.3 {kg ke l p per kg kelp per month}
Total_Kelp_Biomass = Standing_Kelp_Biomass +
Drift_Kelp_Biomass
Stand_Graze = GRAPH(Drift_Kelp_Biomass)
(0.00, 0.0417), (0 .1, 0.017), (0.2 , 0 .00924), (0 .3,
0.00602), (0 .4, 0.00451), (0.5, 0 .00365), (0.6,
0.00279), (0 .7 ,0.00193), (0.8 , 0 .00108), (0 .9,
0.000645) , (1,0.00)
Sea Otters
Female_01 (t ) = Female_01(t-dt) + (Female_BornGo_to_ 2yrs-Die_Youngf) * dt
INIT Female_01 = 0 {otters }
TRANS IT TIME
INFLOW LIMIT =
1 2