Aquatic Species at Risk – Atlantic Salmon (Anticosti Island population – DU9)

Description
Habitat
Threats
Scientific Information
Further Information

Description
The Atlantic Salmon has a fusiform body shape that is somewhat compressed laterally and has an average length of about 457 mm. Its back is blue-green, its sides are silvery with several markings that are either round or x-shaped, and its belly is white. During the reproduction period, the Atlantic Salmon loses its silver colour and takes on a greenish or reddish hue; a few large, white-edged spots then appear on its sides.

School of Atlantic Salmon
D. Danvoye

Habitat
Atlantic Salmon spawn in fresh water, generally in their native river. Juveniles spend one to eight years in fresh water before migrating to salt water in the North Atlantic. After staying at sea for one to four years, adults return to fresh water to spawn. Salmon rivers are generally clear, cool and well oxygenated, with gravel, cobble and boulder substrates.

Did you know that...

• Salmon spawn in freshwater during the fall, the eggs incubate during the winter, and hatch in the spring.
  
  
• Eggs hatch as fry and developp into parr over their first two to four years of life in freshwater.
  
  
• Parr develop into smolts which leave their freshwater environment in the spring and migrate to the ocean.
  
  
• Smolts that grow in the ocean for one year before they return to their native rivers to spawn are called grilse but smolts that grow in the ocean for two or more years before returning to spawn are called salmon.
  
  
• After spawning in the fall, salmon and grilse are called kelts or black salmon and remain in rivers under the cover of ice until spring at which time they return to the ocean environment.
  
  
• Salmon and grilse can spawn multiple times during their life.

Because Atlantic Salmon have a high degree of fidelity to their natal rivers and given their adaptation to the stream they frequent (e.g., difference in morphology, life cycle and behaviour), the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) has identified 16 designatables units (DU) of Atlantic Salmon, 11 of which are considered at risk. Atlantic Salmon of the Anticosti Island population (DU9) reproduce only in the island's tributaries. This population has 25 known salmon rivers.

Distribution range for the Anticosti Island
population of Atlantic Salmon
S. Proulx, DFO 2012

Threats
The causes of the widespread decline of Atlantic Salmon are not well understood. Several major reviews have attempted to identify and prioritize the causes of this situation. The low rate of survival at sea was cited as the primary cause of the decline. The populations are also threatened by climatic changes and environmental changes in the ocean; Aboriginal, recreational and illegal fishing; obstacles in fresh water (e.g. dams); agriculture; urbanization; aquaculture and invasive species. In some cases, the habitat used for freshwater spawning is degraded.

The small size of the Anticosti Island population (about 2,400 individuals in 2008) is cause for concern. Over the past three generations, the number of small (that spent one winter at sea) and large (that spent more than one winter at sea) individuals has decreased, representing a net decline of approximately 40% in the total number of mature individuals.

Further Information
The Atlantic Salmon commercial fishery was closed progressively in Canadian waters from the mid-1980s until the complete closure in 2000. Aboriginal peoples continue to fish in several salmon rivers for food, social and ceremonial purposes. Salmon represents an important cultural tradition to which they attach great value. Lastly, recreational fishing is still authorized. Restrictive management measures are imposed for each river based on abundance estimates. These measures include catch limits, mandatory release of large salmon to the water, and closures of certain watercourses. Salmon habitat is protected under the fish habitat protection provisions of the Fisheries Act.

See also:

Atlantic Salmon, Quebec Western North Shore population.
Species at Risk Public Registry.

Scientific Information

Scientific name: Salmo salar
SARA Status: No status
COSEWIC Status: Threatened (November 2010)