Rio Grande cutthroat
trout (Oncorhynchus clarki viriginalis):
Historic range:
The historic range of the Rio Grande cutthroat trout-the state fish
of New Mexico-likely encompassed all cool waters in the Rio Grande drainage,
including the Chama, Jemez and Rio San Jose drainages, along with suitable
waters of the Pecos and Canadian drainages.
Habitat requirements:
Like most members of the trout family, Rio Grande cutthroat trout require
clear, cold water, naturally-fluctuating flows, low levels of fine sediment
in channel bottoms, well-distributed pools, stable streambanks, and
abundant stream cover.
Current population status:
One of North America's most beautiful fish, pure populations of
the Rio Grande cutthroat trout have been reduced to fewer than 100 tiny
headwater streams, occupying roughly 1% of the subspecies' historic
range. Most remaining populations continue to be threatened by the factors
that lead to this significant diminution of range, including competition
with and predation by non-native trout, and habitat degradation related
to livestock grazing, logging, roads, mining and water diversion. Because
of the small size and isolation of Rio Grande cutthroat streams, most
remnant populations are also vulnerable to environmental perturbations,
such as drought, fire, or freezing temperatures, and problems associated
with small population size, such as loss of genetic diversity and random
fluctuations in population size.
Threats to persistence:
Habitat loss, caused mainly by livestock grazing, water diversions,
logging, road building and urban and agricultural development, and introduction
of exotic fishes are the primary causes of decline. All but the latter
activities adversely affect the habitat requirements of these trout.
Listing Status (as of 02/03):
Center for Biological Diversity and a coalition of groups filed a petition
to list the Rio Grande cutthroat trout as endangered in February of
1998. The U.S. Fish and Wildlife Service initially rejected the petition,
but after CBD and other groups filed suit, they settled, agreeing to
complete a status review by June, 2002. On June 11, 2002, Fish and Wildlife
completed their status review again determining that the species does
not merit listing. The Fish and Wildlife Service's finding admits the
trout has been eliminated from as much as 99% of its historic range,
and that most populations continue to be threatened by introduction
of non-native trout, livestock grazing, logging, road building, dams,
water diversions, and disease. They argue that the existence of just
13 populations with a barrier and over 2,500 individuals is sufficient
to make the species safe from extinction. Even these populations, however,
are not secure because they are found in tiny headwater streams subject
to disturbance from drought, fire or other factors, reinvasion by non-native
trout, and ongoing habitat degradation. CBD, Biodiversity Conservation
Alliance, Carson Forest Watch, Center for Native Ecosystems, Pacific
Rivers Council and New Mexican fisherman Michael Norte filed suit to
overturn this latest finding February 25, 2003.
Note of interest: The Rio Grande cutthroat
was the first North American trout ever observed by Europeans- in 1541
Pedro de Castaņedade Najera, a member of Coronado's expedition, first
saw it, writing of "a little stream which abounds in excellent trout
and otter" (the otter is now extinct in the Southwest) This stream was
in all likelihood Glorieta Creek, southeast of present day Santa Fe,
which is now a barren, ephemeral wash for most of its length probably
because of a combination of livestock grazing and other impacts.
Suit filed to protect Rio Grande cutthroat trout:
PRESS RELEASE
Rio Grande cutthroat trout NEGATIVE
FINDING
CBD COMMENTS on
Rio Grande cutthroat status
