Using King Salmon as an example:
- Average adult produces 5,000 eggs
- A run of 1000 fish (assuming equal gender distribution) produces 2.5 million eggs
- To maintain a steady population, 2 eggs from each female must survive to return as adults
- 2 out of 5,000 is 0.04%
- Roughly 10% of the eggs survive to outmigrate, 250,000 smolt
What's happening to the other 249,000?