Salmon Migration and Ecosystem Interactions

Salmon spend years in the ocean before returning to their natal streams to spawn. They navigate using Earth's magnetic fields and the smell of their home stream. During migration, they undergo physical changes and stop feeding, relying on stored fats. Despite facing numerous challenges, only a few survive to spawn. In death, salmon provide essential nutrients to ecosystems, benefiting vegetation and maintaining stream health. The relationship between salmon and trees is symbiotic, as trees prevent erosion and provide shade, while salmon contribute nutrients.

What natural event transforms small streams into rivers, allowing salmon to migrate inland?

• Spring snowmelt

• Summer droughts

• Heavy autumn rains

• Winter ice melt

How do salmon find their way back to their natal streams?

• Using ocean currents

• Using Earth's magnetic fields and the smell of their home stream

• By tracking the sun's position

• By following the stars

What physical transformation do male salmon undergo during their migration?

• They lose their scales

• They develop a prominent hump and hooked jaw

• They grow larger fins

• They develop a silver sheen

Approximately how many eggs does a single female salmon lay?

• 3,000

• 4,000

• 2,000

• 1,000

What is the average number of salmon that return to spawn from the thousands of eggs laid?

• 5

• 20

• 10

• 2

What nutrients do adult salmon contribute to the ecosystem when they return to spawn?

• Nitrogen and phosphorus

• Calcium and potassium

• Iron and magnesium

• Zinc and copper

How much faster do trees grow along salmon-bearing waterways compared to those without salmon?

• Twice as fast

• Three times faster

• The same rate

• Four times faster

What role do tree roots play in supporting salmon populations?

• They increase water temperature

• They prevent soil erosion and sedimentation

• They filter pollutants from the water

• They provide food for salmon

How do trees help maintain suitable water temperatures for salmon?

• By providing shade that prevents water from warming

• By absorbing excess water

• By releasing cooling chemicals

• By increasing water flow

What is the relationship between salmon and trees described as?

• Independent

• Parasitic

• Symbiotic

• Competitive