Identify important fish habitats and protect them or restore their connections

Context and project description

Most species of fish need several habitats to complete all stages of their life cycle: salt water, rivers, flood plains, marshes, etc. To ensure the survival of these species, it is essential that we protect each of one of their habitats, and also that we maintain the physical links that allow them to move from one habitat to another.

This project has two components: development of an atlas listing important fish habitats throughout the St. Lawrence system and the development of a geomatics tool for identifying sectors with the best conservation potential, while considering the obstacles to the free movement of fish into tributary streams of the St. Lawrence. The goal is to give priority protection to sequences of interconnected habitats that correspond to several stages of the life cycle of fish (such as spawning-fry rearing-growth), as well as major migration corridors.


The Atlas of important fish habitats and their connectivity is a geomatics tool that brings together, in a common knowledge base, many sources of information about numerous fish species in the St. Lawrence. The current version contains information about the spawning, rearing and feeding habitats of many sport-fishing species or species at risk such as the copper redhorse. The Atlas’s content is updated as the project advances: historical field observations (1928–2015), ongoing surveys (1995–2015) and simulations based on numerical habitat modelling. For example, innovative simulations are also being conducted along the St. Lawrence between Montreal harbour and Trois-Rivières to measure the connectivity of habitats used by juvenile stages of northern pike. For now, the Atlas’s source data cover the freshwater and brackish water sections of the St. Lawrence, from Lake Saint-François to Isle-aux-Coudres. Much of the data from the fish surveys carried out by the Quebec Department of Forests, Wildlife and Parks (MFFP) is available in the “Biodiversity” section of the St. Lawrence Global Observatory website. That information is updated annually.

At the same time, a decision-support tool for the free passage of fish is being designed. This tool could potentially be used for conducting risk analyses on invasive exotic species. Ultimately, these new tools will inform decision making concerning conservation and protection of fish habitat in the St. Lawrence and its tributaries, and particularly the preparation of a new version of the conservation plan for the St. Lawrence Lowlands. The next step in this project is to determine the criteria for identifying the aquatic habitats to be prioritized for conservation, protection or restoration.

Responsible department

Government of Quebec

  • Ministère des Forêts, de la Faune et des Parcs

Participating departments

Government of Canada

  • Fisheries and Oceans Canada
  • Environment and Climate Change Canada

Government of Quebec

  • Ministère du Développement durable, de l'Environnement et de la Lutte contre les changements climatiques