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

In the final steps of our analyses, we establish the risks posed to listed species and to
designated critical habitat. Our jeopardy determinations for listed species must be based
on an action’s effects on the continued existence of threatened or endangered species as
those “species” have been listed, which can include true biological species, subspecies, or
distinct population segments of vertebrate species. Because the continued existence of
listed species depends on the fate of the populations that comprise them, the viability
(that is, the probability of extinction or probability of persistence) of listed species
depends on the viability of the populations that comprise the species. Similarly, the
continued existence of populations are determined by the fate of the individuals that
comprise them; populations grow or decline as the individuals that comprise the
population live, die, grow, mature, migrate, and reproduce (or fail to do so).
The structure of our risk analyses reflects the relationships between listed species, the
populations that comprise each species, and the individuals that comprise each
population. Our risk analyses begin by identifying the probable risks actions pose to
listed individuals that are likely to be exposed to an action’s effects. Our analyses then
integrates those individual-level effects to identify consequences to the populations those
individuals represent. Our analyses conclude by determining the consequences of those
population-level risks to the species those populations comprise.
We evaluate risks to listed individuals by measuring the individual’s “fitness” defined as
changes in an individual’s growth, survival, annual reproductive success, or lifetime
reproductive success. In particular, we examine the scientific and commercial data
available to determine if an individual’s probable response to an action’s effect on the
environment (which we identify in our Response Analyses) are likely to have
consequences for the individual’s fitness.
Reductions in abundance, reproduction rates, or growth rates (or increased variance in
one or more of these rates) of the populations those individuals represent is a necessary
condition for reductions in a population’s viability, which is itself a necessary condition
for reductions in a species’ viability. On the other hand, when listed plants or animals
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