Describing how fish use the shipping channel

Project context and description

Wildlife desert or bountiful environment? For more than 150 years, the bottom of the river has been dredged, dug and excavated to allow seaway navigation upstream from Lake Saint-Pierre to beyond Montreal. What effect does this shaping have on fish populations that are likely to be found in a channel thus created? Would it not be an environment inimical to fish because of its depth, the speed of the current and the lack of plant cover?

The question has been moot so far because of the difficulty of safely sampling that part of the River, where the current is strong and the shipping traffic is heavy. The research vessel Lampsilis, acquired by the Université du Québec à Trois-Rivières and designed for sampling this kind of habitat, has enabled the Quebec Ministère des Forêts, de la Faune et des Parcs to explore a long stretch of the shipping channel and gain a better understanding of its use and importance in the life cycle of the fish of the St. Lawrence River.

Results

This inventory program looked at the portion of the fluvial stretch of the St. Lawrence between Lake St Francis and Deschaillons-sur-Saint-Laurent, including Lake of Two Mountains, and comprised four sampling missions from 2007 to 2009. In all, 133 trawls took samples of fish communities in four types of habitat: the channel, its slopes, the shoreline and the deep natural trenches away from commercial shipping.

The results show that the shipping channel is home to a diverse fish community (27 species) distinct from those populating the other habitats sampled. Lake Sturgeon, Sauger, Walleye and Channel Catfish, species of interest to sports and commercial fisheries, are particularly widespread in deep habitats (channel and natural trenches). Deep habitats are used by the juveniles of several species, such as the Lake Sturgeon, Channel Catfish and American Shad. Lake Sturgeon over 30 years old were found mainly in the natural trenches.

This first inventory of the fish of the shipping channel now raises the question of the coexistence of aquatic wildlife and marine traffic, a key issue for St. Lawrence fisheries in a context of sustainable development of the shipping industry. From the standpoint of conservation of biodiversity and sustainable management of species of interest to the fishery, the results of this first description highlight the importance of working to maintain a diversity of habitats in the fluvial stretch of the St. Lawrence.

The authors of the report wish to thank the Fondation de la faune du Québec for their support in publishing the results of this inventory.
Consult the report Les poissons du chenal de navigation et des autres habitats profonds du fleuve Saint-Laurent :
•    Full report  (PDF version) (French version)
•    English summary  (PDF version/ HTML version)

Consult the interactive maps showing the breakdown of species caught on the Web site of the St. Lawrence Global Observatory: https://slgo.ca/bio/?lg=en (select “Fish” – “MFFP-UQTR-Lampsilis”).

Participating departments

Government of Canada

  • Environnement et Changement climatique Canada

Government of Quebec

  • Ministère du Développement durable, de l’Environnement et de la Lutte contre les changements climatiques
  • Ministère des Forêts, de la Faune et des Parcs