Tench in the St. Lawrence River Seaway
Project Title
Population dynamics and distribution of tench (Tinca tinca) in the St. Lawrence River: managing a problematic invader
Project Code
Project Duration
May 2019 - November 2020
Project Description
Tench (Tinca tinca) is an invasive Eurasian freshwater fish that is undergoing a rapid population expansion in the St. Lawrence River (SLR). Introduced to Quebec through the release of live fish into the Richelieu River, it rapidly established self-sustaining populations throughout the SLR and Lake Champlain and has recently been reported in Ontario. Tench is a highly opportunistic fish, which reduces biodiversity, while simultaneously increasing inorganic nitrogen cycling and sediment resuspension, thus compromising water quality and submerged macrophyte beds. An aggressive competitor with native cyprinids for food and space18-20, it is of additional concern in Quebec, where it may adversely affect the endangered copper redhorse. Despite confirmed establishment, little is known about SLR tench populations, aside from increases in reported catches by fisherman. As successful mitigation and management of aquatic invasive species (AIS) requires a clear understanding of establishment, distribution and spread, this project aims to (1) elucidate the scale of the SLR tench invasion and (2) provide a mitigation strategy based on fishery exploitation models.
Participating Organizations