Carbaryl, Carbofuran, and Methomyl - National Marine Fisheries ...

For Figure 3C, an exposure pulse would result in a 1-day spike followed by a decline to
the impacted level based upon the prey toxicity. During exposures resulting in low prey
toxicity, toxicity-limited recovery can occur. After exposure ends a constant rate of
recovery proceeds until control drift is reached or another exposure occurs
preyavail=preydrift(day-1)-floor;
preytox=1/(1+(concentration)^preyslope);
preyrecrate=0.01;
preydriftrec = preyrecrate*preytox.
time=start; spike=(-1+10^(1.654*preyavail))*(1-preytox)
preydrift =preydrift+spike
start ≤ time ≤ end; preydrift=(preyavail*preytox)+preyrdriftrec+floor;
time>end; preydrift = preydrift(day-1)+preydriftrec
Figure 2F is generated by using the output of Figure 2C for a given time as the input for
2D and using the resulting output of 2D as the input for 2E. The resulting output of 2E
produces a single time point in the relationship in 2F. Performing this series of
computations across multiple days produces the entire relationship in 2F. 4D is generated
by taking the outputs of 4A and 4B for the same day. Note the relationship of 4A is
equivalent to 2F. The resulting outputs of 4A and 4B are multiplied to produce a final
ration for a given day. The prey abundance (4B) available for consumption during a prey
spike is capped at a maximum of 1.5*control drift to provide a limited benefit to the
individual fish. The final ration is used as input for 4C to generate 4D.
Population Model
The weight distributions from the organismal growth portion of the model are used to calculate
size-dependent first-year survival for a life history matrix population model for each species and
life history type. This incorporates the impact that reductions in size could have on population
growth rate and abundance. The first-year survival element of the transition matrix incorporates
a size-dependent survival rate for a three- or four-month interval (depending upon the species)
which takes the juveniles up to 12 months of age. This time represents the 4-month early winter
survival in freshwater for stream-type Chinook salmon, coho, and sockeye models. For ocean-
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