Burbot (Lota lota) Conservation Status Review
Review Date = 04/08/2010
Population Size
ScoreF - 10,000-100,000 individuals
CommentProbably 10,000 to 100,000 reproductive adults statewide based on known numbers in Clark Canyon Reservoir, Missouri River Reservoirs, Newlon Creek and Smith River Reservoir, and Kootenai River.
Range Extent
ScoreF - 20,000-200,000 km squared (about 8,000-80,000 square miles)
Comment75,616 square kilometers based on Natural Heritage Program range maps
Area of Occupancy
ScoreF - 500-2,000 km squared (about 125,000-500,000 acres)
Comment605 square kilometers based on Heritage Range Maps and occupancy of 1% of landscape by streams and occupancy of 80% of stream reaches and/or tributaries.
Long-term Trend
ScoreF - Increase (increase of >25%)
CommentLong term trend has been for an increase in numbers of fish and area of occupancy as a result of dams that have created cold water habitats that were not present prior to European arrival. These changes to habitat have likely resulted in an increase of g
Short-term Trend
ScoreE - Stable. Population, range, area occupied, and/or number or condition of occurrences unchanged or remaining within ±10% fluctuation
CommentThe only population in the state that has solid evidence for declines is the Kootenai River population below Libby dam. However, there is anecdotal information of recent declines below Fort Peck Reservoir due to intensive ice fishing and there is concern amongst some biologists about the Clark Canyon Reservoir population and the Missouri and Yellowstone populations in general. Evidence indicates that other populations and the overall statewide population numbers have remained stable within +/-10% over the last 10 years or 3 generations.
Threats
ScoreF - Widespread, low-severity threat. Threat is of low severity but affects (or would affect) most or a significant portion of the population or area.
CommentClimate change, drought, agricultural dewatering, and high winter flows below Libby dam on the Kootenai River all represent threats to the species in Montana.
SeverityLow - Low but nontrivial reduction of species population or reversible degradation or reduction of habitat in area affected, with recovery expected in 10-50 years.
CommentSpecies is capable of recovering quickly if suitable habitat is available (within 10-50 years). Prevention of agricultural dewatering is probably the best opportunity for management action that will improve and protect Burbot habitat. Dams may mitigate
ScopeModerate - 20-60% of total population or area affected
Comment20-60% of the population in Montana is likely to be impacted by reduced water flows and increased water temperatures that will make it difficult for them to persist in these areas within the next 15 years.
ImmediacyLow - Threat is likely to be operational within 5-20 years.
CommentSpecies managed recent drought years reasonably well.
Intrinsic Vulnerability
ScoreB/C -
CommentSpecies has relatively high fecundity with up to 3.5 million eggs laid per large adult female, age to sexual maturity is 3-5 years, and animals can live to 30+ years.
Environmental Specificity
ScoreB - Narrow. Specialist. Specific habitat(s) or other abiotic and/or biotic factors (see above) are used or required by the Element, but these key requirements are common and within the generalized range of the species within the area of interest.
CommentSpecies is dependent on cold water habitats throughout its range (10-12 degrees C preferred and avoid temperatures above 13 degrees C), but cold water habitats are still reasonably widespread in Montana.
Raw Conservation Status Score
Score
3.5 + 0.0 (population size) + 0.0 (area of occupancy) + 0.0 (short-term trend) + 0.0 (threats) = 3.5
