Canada’s Oceans Now: Arctic Ecosystems 2023 - Response of Arctic Char to habitat change

Response of Arctic Char to habitat change
Arctic char are responding to more than one change in their habitat. This creates opportunities and challenges.

In the center, two people are seen hanging char to dry on a frame.

Text above states:

• Char typically winter and spawn in lakes and migrate to the ocean in summer to feed

Text below states:

• “Arctic char is culturally important for Indigenous communities. They are critical for nutrition, local food security, culture, and well-being.”

 A large river flows from the top right of the infographic, down to the center, and back up to the top left. Many char are seen swimming along this river; they are large and abundant on the right side, while those on the left are small, sparse and one is floating belly up.

The left side of the river is colored in orange and yellow, with text scattered throughout explaining the risks arising from warming river water:

• Some rivers are already warming to over 20°C
• Warming habitats can harm Arctic char activity and health
• Char will need to change their behaviors to find cooler habitats
• Char may be forced to change the timing or location of upstream migrations to avoid high river temperature

The right side of the river is colored in blue, yellow and red shapes represent char prey. Text scattered throughout explaining the benefits gained from a longer ice-free season, two prey items of the char (orange amphipod and red krill) are enlarged and shown in circles:

• Char can access the ocean earlier and stay there longer to eat more marine pray (such as the amphipod and shrimp illustrated within this side of the river)
• Char may be more fat and be in better condition
• May result in higher quality fish for community harvest.

At the bottom left, a box highlights the risks of increasing temperatures shown by measuring char activity. At 16°C, char hearts are stressed but the fish remain active; a char silhouette is shown in a dynamic pose with many wavy lines behind it, a heart icon above is nearly full . At 20°C, their hearts begin to fail, and activity slows; a char silhouette is shown in a more static pose with slightly wavy lines behind it, a heart icon above is half full. At 23°C, swimming is no longer possible; a char silhouette is shown in a limp pose with no wavy lines behind it, a heart icon above is nearly empty. A separate box off to the right states:

• previous exposure to warm waters may help char tolerate some warming temperatures.