To address key data gaps identified in recovery planning for Puntledge summer Chinook, a freshwater survival study was initiated as part of the larger Bottlenecks Project in partnership with the Department of Fisheries and Oceans Salmon Enhancement Program (DFO-SEP). The study focuses on assessing juvenile Chinook mortality during downstream migration in relation to hydroelectric infrastructure and habitat conditions. Paired groups of PIT-tagged fall-run Chinook juveniles (as a proxy for summer Chinook) were released upstream and downstream of the BC Hydro diversion dam to estimate survival and migration rates through this critical reach. This approach is informed by prior PIT-based research in other systems (e.g., Cowichan River) that has shown the effectiveness of this method in identifying areas of loss during emigration.

Visual of Mobile Scans conducted. (test)

This is the first draft of the Bottlenecks Weekly Update Report. The objective is to provide ourselves and project partners (First Nations, DFO, Streamkeepers etc.) with an up to date report that provides a good overview of the current return data.

The impact of climate change on salmon stocks along the Pacific Northwest is a crucial issue, given that the muting or complete removal of specific life-history characteristics in salmon stocks have altered run timings and depressed adult returns. Climate change-related impacts and ecosystem alterations are uniquely present worldwide, and a recent report published by the Cowichan Valley Regional District (CVRD) has outlined these potential impacts on the Cowichan Valley and, specifically related to this study, the Cowichan River. Understanding the impacts of different hydrological and temperature regimes on the expression and success of certain traits in salmon species is essential in understanding climate change impacts. Fish otoliths have been used extensively for providing the most accurate fish age determinations due to their continued growth throughout life. Juvenile Chinook salmon life histories can be determined using minor elements, and the ability of managers to utilize data that demonstrates the impacts different hydrological regimes have on the success of certain traits can be of great use in regulated systems such as the Cowichan River.