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Fish Habitat

What is a fish habitat?

A fish habitat is made up of a set of living environments providing food resources, shelter, reproduction sites (spawning grounds) or growth sites (fry rearing areas), and migratory routes necessary for fish survival (source: Department of Fisheries and Oceans).

Why should we protect these habitats?

  • To ensure fish survival.
  • Because fish is an essential food source for our communities and for other animal species.
  • The protection of fish habitats ensures quality water for our consumption or recreational activities.

How do fish habitats degrade?

Erosion

  • When the shores lack vegetation (due to agriculture, logging or modification of the riparian strip), minerals, fertilizers and chemical products accumulate in the water. Sand and earth also accumulate, which causes sedimentation.
  • Sediments, minerals and fertilizers transported in the water favor the growth of algae and aquatic plants. In large quantity, the plants reduce the quantity of oxygen available for the fish. Certain kinds of algae are even dangerous and can render a lake unfit for bathing (Ex: Blue-green algae)
  • Destruction of spawning grounds: sand falling into the water can cover spawning grounds, reducing the level of oxygen required for fry and thereby destroying these spawning grounds.
  • Irritation of gills: Fish gills filter water, which allows them to breathe. Spawning grounds affected this way can remain unavailable for several years.
  • Sedimentation also reduces the availability of fish food, which mainly consists of insect larva living on the bottom of watercourses. After the deposit of sediments, this food is no longer accessible. In addition, this reduces visibility, which reduces fish movement and hinders their feeding.

Documents of reference

  • Construction of dams: The construction of dams fragments fish habitats. Lakes, rivers and brooks that were previously accessible for spawning, feeding or migration become unattainable for fish.
  • Household activities: Household activities such as washing and cleaning often involve products containing chemicals and phosphates. These pollutants are found in the environment and can lead to the proliferation of aquatic plants.
  • Acid rain: Acid rain reduces the water quality by acidifying it; the direct effects of acidification on fish include a high mortality rate, disturbance of growth rate and reproduction, and chronic damage to organs and tissues. The indirect effects of acidification are the degradation of fish habitats and changes to predator-prey relationships (interruption of the food chain).
  • Introduction of new species: Several species have been introduced into watercourses and have replaced indigenous species. In certain watercourses, fishing with live minnows has caused the introduction of several species. In other watercourses, fishing fanatics have introduced their favorite species in bodies of water to the detriment of indigenous species. Certain plants such as Eurasian water-milfoil (introduced from Europe) have also been introduced. These plants proliferate very quickly and take the place of other plants. They create uninhabitable environments for fish since they are anoxic (without oxygen). They also cause problems for bathing and boating.

How can we protect these habitats?

  • Use household cleaning products and soaps that are phosphate-free and biodegradable: Small everyday actions have a big impact if everybody gets involved!
  • Avoid the disposal of toxic products in our watercourses: For example, be careful not to spill oil or gas into the water. Never throw out toxic products such as old batteries, pesticides, or paint in our household garbage; special collections exist for these waste matters!
  • Reduce the use of motor boats
  • Conserve and maintain plants on the shoreline (riparian strip) : These plants provide shelter and reproduction areas for certain species, filter pollutants, cool the water with shade and prevent erosion. It is best to leave the riparian strip intact! Do not circulate there.
  • Do not drive through watercourses or remove gravel: This destroys fish habitats; use the bridges!
  • Clean the boat and propeller thoroughly before moving to another body of water: This way you avoid carrying plants and undesirable organisms to other watercourses.

How can we get more information ?

To obtain a list of projects related to fish habitats, contact us.