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

Risk Characterization
We follow the framework presented in Figure 2 to conduct the analysis and risk
characterization phases. First we conduct exposure and response analyses to
estimate/determine the type, likelihood, magnitude, and frequency of adverse responses
resulting from predicted exposure based on the best available information. We evaluate
species information and pesticide information to determine when, where, and at what
concentrations listed salmonids and their habitat may be exposed. We then correlate
those exposure estimates with probable response based on available toxicity data. Once
we have conducted the analysis phase, we move to the risk characterization phase (Figure
2).
In the risk characterization phase, we revisit the risk hypotheses and apply tools to
address whether any individual fitness consequences assessed in the analysis phase would
be expected to impact populations and ultimately species. One of the tools we employ is
individual-based population models predicated on a juvenile salmonids’ probability of
survival in its first year of life. We also assess interactions between the stressors of the
action and stressors in the Environmental Baseline (Figure 2). Some pesticides’ toxicity
profiles are influenced by environmental parameters such as pH and temperature.
Temperature can affect pesticide metabolism in fish and is seasonally elevated in many
salmonid supporting watersheds. As described earlier in this section we translate
expected effects to identified PCEs by evaluating the available information to support
risk hypotheses. If we expect PCEs to be reduced we discuss whether the expected
reductions translate to reductions in the conservation value of designated critical habitat.
To conclude consultation, cumulative effects are described and the extent to which
species and habitat are affected is documented. Cumulative effects as defined in 50 CFR
§404.2 include the effects of future, state, tribal, local, or private actions that are
reasonably certain to occur in the action area of this Opinion. Integrating the Effects of
the Proposed Action, the Status of Listed Resources, and the Environmental Baseline,
NMFS determines whether EPA’s pesticide registration action jeopardizes the continued
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