Bonneville cutthroat trout
Once thought to be extinct, the Bonneville cutthroat trout is making a comeback.
The Bonneville cutthroat trout, Oncorhynchus clarki utah, is a subspecies native to the Bonneville basin. Click here Bonneville cutthroat trout evolved primarily as a lake-dwelling population in Lake Bonneville during the Pleistocene Epoch. As Lake Bonneville shrunk to remnant lakes at the end of the last ice age, the subspecies became increasingly restricted to stream-dwelling populations in the isolated river drainages that formerly emptied into Lake Bonneville. Because the river systems are naturally isolated, biologists divide the Bonneville basin into Geographic Management Units or GMUs.
Within the Bonneville Basin, human activities have altered aquatic habitat and the physical processes that create and maintain that habitat, resulting in a significant decline in fish populations. Bonneville cutthroat trout were thought to be extinct in the early 1970s, but recent work has revealed several genetically pure populations interspersed throughout its range. In order to prevent its listing as a sensitive species by state and federal agencies, a conservation agreement was signed by the state and federal entities responsible for Bonneville cutthroat trout conservation.
Population status in Utah
In 1978, only six Bonneville cutthroat trout populations were known to exist in Utah. Field investigations by many agencies and groups have increased our knowledge of Bonneville cutthroat trout occurence throughout its range. Known population numbers increased to 29 by the early 1990s. By the year 2000, 261 populations of Bonneville cutthroat trout had been identified in Utah. Over the last 30 years, Bonneville cutthroat trout populations have been expanded in every management unit in Utah. Presently, Bonneville cutthroat trout brood populations exist in all the management areas of the state. With these brood populations, Bonneville cutthroat trout can be stocked into even more areas within their historic range to provide both sportfisheries and population expansion.
The Utah Division of Wildlife Resources (DWR) is the lead agency in developing and implementing the Range-Wide Conservation Agreement (Utah, Wyoming, Idaho, Nevada, Goshute Tribe, several federal agencies and nonprofit groups). The DWR sponsored a genetics conference for the western states and developed a position paper that is recognized as a very important document regarding genetic verification protocol for all cutthroat trout in the western United States. The conservation of this subspecies has involved biologists at all levels and regions of many agencies and organizations. Funding and conservation efforts continue and have been instrumental in preventing this subspecies from being listed.
The objectives of the conservation agreement are as follows:
- Restore and maintain at least 53 conservation populations throughout 294 stream miles and 35,775 surface acres including a sufficient number of metapopulations where possible within five GMUs.
- To eliminate or minimize threats to Bonneville cutthroat trout and its habitat to the greatest extent possible.