WSP07668

• File Number: 8240.200.10.C.5
• Description: UCRBRIP
• Basin: Colorado Mainstem
• Date: 3/21/1994
• Author: USFWS
• Title: Federal Register - Determination of Critical Habitat for Four Colorado River Endangered Fishes - Final Rule
• Water Supply Pro - Doc Type: Publication

13382 . Federal Register I Vol. 59, No, 54 I Monday, March 21, 1994 I Rules and Re~,'ulations

. Congress believed that the "worth" or
value of a species is incalculable and
invaluable. 'This is supported by the
Supreme Court interpretation of the Act
in TVA v, Hil1.437 U.s, 153,178 (1978).
This concept is applicable to the Basin
as it represents one of the most
distinctive collections of flora and fauna
in North America.
The economic analysis and data used
duting the exclusion process addressed
impacts to: river basin or sub-basin by
State, each State as a whole, the region,
and the Nation. Direct and indirect
impacts on.employment, wages, and
State and Federal revenues from .
business and personal income taxes also
were considered during the exclusion
process, . ..'

Threshold ofS;gmficant Economic
Impact . . " .
To establish the threshold for
significant economic impact, impacts
were evaluated in the context of the
nonnal fluctuations of the economy
(Brookshire,et al..1994). Over the period
1959-1991. the growth rate of the .
national economy (measured'as .
percentage-change in Gross Domestic
Product) varied from - 2.2 percent to
6.2'percenl.'.The'mean growth rate was
2;85 percent.{with a standard deviation
(SD) of 2.26 percent), Over.the same
period, tJui:average unemployment rate
was 5.95 perilsnt (SI>=1.52 percent), '
Impacts thatlie:mthin this range are
. within thelimmal fluctuations of the
economy.andlll8 able to be absorbed by
the economy. A 'conservative threshold
forsill"i!;""~impactswould be a 1"
percent SD from the projected baseline.
If changes in'employment or output due'
to critical habitat at a State level exceed
this threshold, then that area of critical
habitat should be considered for
economic exclusion.
Various flow and nonflow impacts
were evaluated in the economic analysis
(Brookshire at aL1993. 1994), Impacts
associated with providing flows for
fishes. including reoparation of
mainstream dams. constituted the
greatest mcmetary impacts, Flows in one
reach may.be dependent on the flows
from reaches upstream. Therefore, e_ven
though a reach may be excluded fot
economic reasons, those economic
impacts may not disappear due to
downstream flow requirements of the
fish. Thus,.the sma1lest unit examined
for economic impact was an individual
river exceptforthe mainstem Colorado
River, wbich was by river reach,
Many of the critiCal habitat reaches
were designated for more than one of
the endaDgered.fishes. Therefore, some
reaches were needed for the eventual
recovery of one species, and also needed

to prevent extinction of another. The
dual nature of many of the designated
reaches and other issues made the
exclusion process. complex.

Conservation and Extinction as Factors
in Designating Critical Habitat

The Act defines "conservation" to
include the use of all means necessary
to bring about the recovery of an
endangered or threatened species.
Section 7(a)(2) prohibitions against the
destruction or adverse modification of
critical habitat apply to actions that
would impair survival and recovery of
a listed species. As Ii result of the link
between critical habitat and recovery.
these prohibitions should protect the
value of critical habitat until recovery.
SurVival and recovery, mentioned in the
. definitions of adverse modification and
jeopardy. are conceptually related, The
survival of a species may be viewed. in
part, as a progression between .
extinction and recovery of the species.
The closer a species is to recovery, the
greater the certainty of its continued
survival. Theterms,usurvival" and..
"recovery" differ by the degree of
confidence about the ability .of a species
to pemst in nature over s given period.
Critical habitat consists of areas that
contain elements that are esSential to
the conservation of a listed species.
, Critical habitat identifies areas that.
should be considered in the
conservation'effort and provides
additional protection to those areas
through section 7 consultation. Critical
habitat is designated to contribute to a
species' conservation; however, not all
areas proposed as critical habitat may be
necessary to prevent extinction.
Consequently, some areas or portions of
ereas may be excluded due to economic
considerations, provided that such
exclusions would not result in the
extinction of the species.
In its designation of critical habitatior
the four Colorado River fishes, the
Service has identified habitat required
for recovery of esch speCies and
delineated reaches that contain habitat
features needed for.spawning, rearing.
feeding, and migration. Species
conservation is related to s number of
factors. such as the number of
individualS, the amount of habitat, the
condition of the species and its habitat,
the species' reproductive biology, and
the genetic composition of the
rem.ining populations. Through its
previous efforts (e.g.. section 7
consultation, research), the Service also
has identified biologically important
ereas that still support.these endangered
fish. Additiona1ly, important reaches
have been identified in recovery plans
for the Colorado squawfish, humpback

chub, and bonytail chub, The Recovery
Implementation Programs in the Upper
Colorado River and San Juan River
Basins have also identified essential
reaches for these species, Although all
ereas proposed are important to
conservation, those areas currently
supporting the largest remaining
populations may be key to the long.term
survival of these species, Additionally,
the physical and eCological
relationships between these ereas ere an
important consideration.
Extinction of the four Colorado River
fishes would most likely occur as a
result of the presence and continued
introductions of nonnative fishes.
significant changes in the .hydrologic
cycle. increased fragmentation and
channelization of their habitat, and
decreased water quality. Although a
single action could result in extinction,
the cumulative reduction in suitable
habitat resulting from many actions also
could lead to species extinction,
Because these species are long-lived, the
specific effects of some impacts are
difficult to establish:''I'berefore; the
exclusion analysiS' focuses not only on '
specific rivers and/or reaches, but also
on their relationship to othei'reaches in
evaluating whether or not extinction
would be proba'blelf ared Wiire'
excluded. Such factors as: (t) Current
population status, (2) habitat quality .
(e.g., presence Ilf l!Pllwning site<;"" .
nursery areas. and condition of the .
habitat), (3) geographical distribution of
the populations, (4) genetic v~bility
within the population, and (5) the
relationship between critical habitat
units were considered.... ".
In order to detertnine'river reaches
required to prevent extinction (ensure
survival) of these fishes. the Service
relied upon available biological .
information and approved recovery
plans. Information relating to the
species' biological and ecological needs,
such as habitat, reproduction, rearing,
and genetic<;, was used in determining
if an erea was needed to prevent
extinction of the species. Where enough
information was available, specific
recovery plans presented downlisting
and delisting criteria; Downlisting
criteria were generally equated to the
survival level; delisting criteria were
related to the recovery level. Because no
recovery plan has been prepared for the
razorback sucker, reaches required for
its survival (downlisting) and recovery
(delisting) may change as a recovery
plan is developed by the Service and the
Colorado River Fishes Recovery Team.

Exclusion'

After considering the economic and
other factors that may be pertinent to