Gerrard Rainbow Trout Stock Productivity at Low Abundance
This project will get recruitment information at low stock abundance, which is critical in defining important biological reference points for conservation and management of Gerrard Rainbow Trout on Kootenay Lake. The data will provide important information on the maximum reproductive rate, which can only be obtained when stock abundance is low. Nighttime snorkel surveys will be conducted to estimate the abundance of age one juvenile Gerrard Rainbow Trout in the Duncan River. The data will be combined with information obtained from the Lardeau River to provide whole river estimates and annual production of age one juvenile Gerrard Rainbow Trout.
As a result of the recent collapse of Kokanee, and subsequent decline in the Gerrard Rainbow Trout population, benefits of this work will provide a better understanding of the expected timeframe for the recovery of the stock. In addition, spring survey information will be useful for managers to determine the extent of the declining Gerrard juvenile recruitment and potential reduction in predation to Kokanee on Kootenay Lake.
Final Report: Executive Summary
Annual stock assessment of the juvenile Gerrard Rainbow Trout (Oncorhynchus mykiss) population in the Lardeau and Duncan rivers is considered a management priority within the Kootenay Region. Assessing and determining the Gerrard rainbow trout stock’s reproductive capacity and productivity is essential for managing this highly exploited population. Assessment of the in-river juvenile abundance in unison with adult escapement data provides important information for defining a stock-recruitment relationship used in determining useable biological reference points for management of this unique population. The recent unprecedented collapse of the lakes’ Kokanee population has provided an ideal opportunity to obtain information on the population dynamics at low stock abundance, a key data piece required for determining stock status. This report summarizes spring 2016 survey work conducted on the Lardeau and Duncan rivers to assess juvenile recruitment at low stock abundance.
Click the provincial database link below to read the full final report for this project.