Salmon divergence. Salmon eggs are laid in freshwater streams typically at high latitudes. The eggs hatch into alevin or sac fry. The fry quickly develop into parr with camouflaging vertical stripes. The parr stay for six months to three years in their natal stream before becoming smolts, which are distinguished by their bright, silvery colour with scales that are easily rubbed off. Only 10% of all salmon eggs are estimated to survive to this stage. The smolt body chemistry changes, allowing them to live in salt water. While a few species of salmon remain in fresh water throughout their life cycle,
Salmon run as vertical slot fishways to provide increased access for a range of biota, including poor swimmers. Skilled predators, such as bears, bald eagles and fishermen can await the salmon during the run. Normally solitary animals, grizzly bears congregate by streams and rivers when the salmon spawn. Predation from Harbor seals, California sea lions, and Steller sea lions, can pose a significant threat, even in river ecosystems. Black bears also fish the salmon. Black bears usually operate during the day, but when it comes to salmon they tend to fish at night. This is partly to avoid competition with the more