Project Overview

Redd counts are a commonly applied tool in fisheries science and

management and have been used to assess population status and trends of Finespotted Snake River Cutthroat Trout spawning in groundwater-fed tributaries of the upper Snake River watershed since the 1960s. However, considerable rates of redd superimposition have been observed in these streams and is thought to affect the accuracy and precision redd count data and potentially limit recruitment via the destruction of previously laid eggs and fry. The goal of the project is to evaluate the relationships between redd count data and spawning population size, spawning success, and fry emergence. This information will allow for recommendations on how to most effectively conduct redd counts moving forward and if these counts can be compared to historical data. Additionally, understanding how an individual redd contributes to the population will provide managers with better information regarding the importance of groundwater-fed spawning tributaries to the overall abundance of Finespotted Snake River Cutthroat Trout in the Snake River drainage.