The Zec River to Mars is a "zone d'exploitation contrôlée" (controlled harvesting zone) (ZEC) in the unorganized territory of Lac-Ministuk, in the Le Fjord-du-Saguenay Regional County Municipality, in the administrative region of Saguenay-Lac-Saint-Jean, in Quebec, in Canada.

Established in 1995, the ZEC is administered since May 2008 by the non-profit organization "Contact Nature Rivière-à-Mars", whose mission is the operation of this river that runs through public lands.

From its source in Lake Mars in the Laurentides Wildlife Reserve, the river flows on 106 km north to "La Baie des Ha!

Mars River has cold water, many rapids and falls, and a rocky bottom that are well suited to the Atlantic salmon for his journey from the sea to the pits of reproduction.

The "Association des pêcheurs sportifs de la rivière à Mars" (APSRM) was formed in 1983 to administer the operation of the river.

Apart the Atlantic salmon, seven major species abound in the waters of the basin of the "Mars River": the brook trout, the longnose dace, red miller, the "black suckers", the American eel, the stickleback and northern pearl dace.