The Greenback Cutthroat Trout
The following information discusses the recovery plan for the
green back cutthroat trout, a currently threatened species.
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| Arkansas River, Habitat of the Greenback Cutthroat Trout http://upload.wikimedia.org/wikipedia/commons/8/8f/Arkansas_head_waters.jpg |
Important Key Terms to Know:
- Threatened – vulnerable to endangerment in the near future
- Angler Pressure – rod and line fishing
- Brood stock – population of mature individuals used for breeding purposes
- Non-Salmonids – fish from a distinct subspecies (not salmon family)
- Spawning – deposit of eggs
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| Drawing of a greenback cutthroat trout http://www.brucelbunch.com/images/Greenback_Cutthroat.JPEG |
Description and Ecology of Organism
The Greenback Cutthroat Trout, commonly referred to as a greenback,
is the only trout species endemic to the headwaters of the South Platte and
Arkansas River Drainages. The subspecies of trout inhabits cold-water streams
and lakes that have sufficient springtime spawning habitats. Like its name suggests, a mature male greenback displays a green colored back and a crimson red underbelly. The greenback is one
of the most colorful and rare subspecies of trout. It is difficult to find pure
populations of greenback that have not hybridized with other subspecies.
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| Historic distribution of greenbacks, location of historic sites, and stable reproducing populations.
Behnke, R. j. and M. Zarn. 1976. Biology and management of threatened and endangered western trout. USDA Forest Service, Rocky Mountain Forest and Range Experimental Station. General Technical Report RM-28.
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Geographic and Population Changes
Although once abundant, the greenback’s numbers started
declining in the late 1800s. By the early 1900s, the majority of greenbacks
were extirpated from their native range. In 1973, only two small populations of
greenbacks were confirmed. These two populations represented less than roughly
2,000 greenbacks in less than 4.6 kilometers of stream.
Today, and post restoration, greenbacks are present in 62
sites in a total of 179 hectares (442 acres) of lakes and ponds and 164
kilometers (102 miles) of stream habitat. 47 of these sites are open to catch-and-release.
20 populations (both historic and restoration populations) are stable, meaning
the populations are self-sustaining. 17 of these populations are in the South
Platte drainage and 3 are in the Arkansas drainage.
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| Arkansas River Drainage http://upload.wikimedia.org/wikipedia/commons/2/27/Arkansasrivermap.jpg |
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| South Platte River Drainagehttp://upload.wikimedia.org/wikipedia/commons/0/05/Southplatterivermap.png |
Listing Information
The greenback trout was initially listed as “endangered” in
1973, but the subspecies was down listed to “threatened” in 1978. The recovery
objective is to restore the greenback subspecies to a non-threatened status within
their native range. Recovery is considered complete when at least 20 stable
populations covering at least 50 hectares (124 acres) of lakes and ponds and 50
kilometers (31 miles) of stream habitat have been established. Although these
criteria have been met, the greenback cutthroat trout remains listed as “threatened”
because according to the US Fish and Wildlife Service and their Greenback
Cutthroat Trout recovery plan, two main things need to occur in order for the
species to be delisted:
- Two additional stable populations established in the Arkansas River drainage
- Preparation of long term management plan to guide management post recovery
Cause of Listing and Main Threats to its
Continued Existence
The greenback population declined due to the loss of habitat
caused by mining and agriculture, over harvest, and the introduction of
non-native trout species. Competing non-native species are rainbow trout, brook
trout, brown trout, and Yellowstone cutthroat trout.
Primary limiting factors include: (according to US Fish and Wildlife Service)
- Other spring spawning trout that hybridize with the green back
- Competing fall spawning species (these species compete for food and space)
- Over harvest of greenbacks
Description of Recovery Plan
As a result of the recovery efforts, captive brood stock
populations have been established, non-native trout were removed from suitable
habitat, and greenbacks were re-introduced into their native range. Lastly,
stable populations of greenbacks were developed and catch-and-release fisheries
were created. The year of recovery was
supposed to be in 2000 and the overall cost of recovery was estimated to be $634,000.
Check out this video and article explaining detailed efforts to create brood stock populations of green backs in Leadville, Colorado: http://www.denverpost.com/environment/ci_26420672/greenback-cutthroat-trout-recovery-gets-stronger-colorado-project#ooid=VqMWl3bzpNM2M5WnuIOXiXFDN95h42xK
According to the U.S. Fish and Wildlife Service, the
recovery process for the greenback species consists of seven main objectives.
The following list can be found online in the official green back recovery plan
(see link listed below).
- Maintain or enhance all known Type A greenback cutthroat trout populations and their habitats
- Establish or document the existence of 20 stable populations of pure greenback cutthroat trout within the subspecies’ historic range.
- Establish hatchery and wild populations of pure greenback trout for brood stock.
- Document response to angler pressure, stocking rates, fish diseases, fishing regulations, and native non-salmonids
- Conduct an information and education program.
- Promote partnerships with conservation groups and explore alternative management and funding strategies
- Prepare a long-term management plan and cooperative management agreement for the greenback cutthroat trout
Fortunately, several aspects of the plan have been met and
the greenback cutthroat trout species has greatly recovered within its native
range. However, before greenbacks can be de-listed the two main criteria
(listed above in section #3 must be met). Until these two criteria are met, the
Greenback Cutthroat Trout remains a threatened species.
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