Habitat Role of Lakes for Atlantic Salmon – Terra Nova River

This project will contribute to better understanding of how salmon use lacustrine habitat in the face of changing climate conditions.

The study will assess the function of lakes in the Terra Nova watershed in providing habitat for upstream migrating salmon, their role in providing cold water refugia during high summer water temperatures and determine the length of time that salmon remain in lakes during both the pre- and post-spawning periods. During their pre-spawning residency, it will identify the spatial distribution of salmon as well as the water temperatures and depths frequented by salmon. It will help determine if shoreline spawning is occurring in the lakes and also identify frequently used and critical areas of lakes to add in future stock protection and/or habitat improvements. It will also determine if salmon use lakes post-spawning to take advantage of higher water temperature than in riverine habitat and avoid extreme winter flow conditions.

Acoustic receivers will be deployed at the main inlets and outlet of lakes to monitor salmon movement and residency times in addition to water temperature. In Terra Nova Lake, up to forty receivers will be distributed widely around the lake such that they will communicate with each other. This will allow triangulation between receivers to pinpoint where the tagged fish spend their time over their residency in the lake. A smaller number of specialized sensor transmitters will be supplied by DFO to record water temperature and depth over the salmon’s period in the lake. Data from the receivers will be downloaded at the appropriate time in the autumn and again in the spring. FABEC will also tag forty to fifty salmon with acoustic transmitters in the vicinity of Big Falls, which is located about 5 kilometres below the outlet of Terra Nova Lake. Options for capturing the fish include a temporary fish trap at the fishway, using a pole seine, or carefully electrofishing in the pool area above the falls.

The project results will be compiled in a concise report to help improve knowledge and understanding of salmon use of lakes in Newfoundland rivers and aid in other efforts related to watershed planning.