Cooperative Research Units
Education, Research And Technical Assistance For Managing Our Natural Resources
Home | Intranet | Digital Measures | Help

Lake trout population modeling and annual assessment of suppression netting


September 2016 - August 2021


- The Native Fish Conservation Plan specifies that the goal for lake trout suppression is to reduce lake trout population growth rate to 0.85 for 10 years (secondary desired outcome). Thus, lake trout catch per unit effort (C/f) in distribution netting (i.e., assessment netting) will decrease 15% per year to 0.1 fish per 100-m net night if suppression is successful. The goal for Yellowstone cutthroat trout abundance is to increase C/f above 10.

Annual distribution netting conducted by the National Park Service is a prerequisite for assessing population metrics. Data from distribution netting will be used to estimate temporal change in C/f using linear models and paired t-tests. Distribution netting data will be used to estimate size structure for Yellowstone cutthroat trout and lake trout using length-frequency histograms and cumulative-frequency distributions. Lake trout and Yellowstone cutthroat trout age data collected by the National Park Service will be used to create an age-length key to estimate age structure and total annual mortality will be estimated using catch curves. Lake trout total annual mortality will be converted to an estimate of exploitation (Miranda and Betolli 2007). Exploitation represents the fraction of the population being removed; therefore, lake trout abundance will be reconstructed by dividing total catch by the exploitation rate (Syslo et al. 2011). Reconstructed population estimates for will be evaluated for trend (Syslo et al. 2011).


Current Staff

Federal Staff: 101

Masters Students: 239

Phd Students: 154

Post Docs: 55

University Staff: 241

5 Year Summary

Students graduated: 695

Scientific Publications: 1962

Presentations: 4417



Funding Agencies

  • Yellowstone National Park


Cooperative Research Units Program Headquarters Cooperators

  1. U.S. Geological Survey