Animals and plants of the ocean and land rely on one another. Marine and forest ecosystems are joined in a complex web of life.
Salmon Feed the Forest
The interconnection between ecosystems can be seen in Gwaii Haanas National Park Reserve, British Columbia. There, salmon follow rivers into the heart of the forest, past the great Sitka spruces that grow on the banks.
- Upon spawning, the salmon die.
- Their bodies are hauled up on land by scavengers such as bears and eagles.
- The scavengers feed on the salmon and leave some of the carcass behind.
- The carcass eventually breaks down, leaving nutrients in the soil.
- Those nutrients become available to other living things, such as Sitka spruce (Picea sitchensis), which are fertilized through their roots.
Salmon Need the Forest
The exchange of nutrients works both ways. The fish give to the forest, but they also require the nutrients and stability of a healthy forest to survive as young fish.
- A healthy forest supports a healthy ecosystem. The salmon rely on the animals in this ecosystem for food.
- Inshore, where salmon feed, depends on a healthy forest.
- The creatures that live along the shore are fed by nutrients from the forest, which are washed from the interior by rain and streams.
Nutrients from Fish Found in the Trees!
Researchers at the University of Victoria, in British Columbia, have found that salmon contain a form of nitrogen that doesn't occur in terrestrial (land) animals.
The nitrogen can be tracked throughout the entire forest ecosystem, from Sitka spruce to maggots. The traces show how nutrients from the salmon's body are absorbed by other plants and animals.
Salmon farming is a topic rife with controversy. Some ecologists say that the activity is a danger to marine ecosystems.
On the other hand, businesses and governments say that the farming can be done in a controlled and safe way.
Check out these links to explore both sides of the issue:
David Suzuki Foundation
Fisheries and Oceans Canada