Diet of anadromous brook trout in the Saguenay Fjord and River

Fishing success for anadromous brook trout (sea trout; Salvelinus fontinalis) has declined in recent years in both the Saguenay Fjord and River, suggesting a population decline. This ecotype therefore needs to be managed as a priority to ensure the sustainability of the resource. This study will focus on sea trout feeding in the Saguenay River–Fjord system to assess whether the availability of food resources is a factor that could limit brook trout growth.

Sampling will be conducted in collaboration with the MELCCFP, through the Pêcheurs Repères program, in which volunteer citizens donate the heads and viscera of anadromous brook trout they have caught during the fishing season. The brook trout stomach contents will be analyzed, and all organisms found will then be identified, counted and weighed. These analyses will allow us to detect seasonal and spatial patterns in feeding and determine any changes in feeding or food resources over recent years.

Anadromous brook trout prey (fish, crustaceans and others) will also be sampled as part of a larger-scale project assessing the Saguenay food web. The energy density of the prey, i.e., the number of calories per gram, will be calculated with the long-term aim of using this data to construct an energy budget for brook trout in the Saguenay River–Fjord system.