Salmon life cycles
The salmon’s life cycle has changed little since it’s origins 100 million years ago, only evolving with the glaciers and the earth’s environmental change. Biologically they are primitive fish compared to other fish. They have primitive air bladders and no spines on their fins. Their life cycle is also very primitive, salmon are anadromous which means they hatch in fresh water but spend most of their life in the ocean and return only to fresh water streams to spawn.
When salmon hatch they stay in the gravel for 180 days depending on the certain conditions like the water’s oxygen content and temperature. Many of the other eggs die before they even hatch due to disease and not being fertilized. While in the gravel the young salmon use their yolk sac as their source of food, but when they run out they eat insects. Salmon stay in fresh water for 1-3 years until they go to the oceans.
While in the ocean they eat other fish, plankton, crustaceans, and squid. While they may be big time predators for some animals they are also prey to whales, harbor seals, and just about anything with webbed feet. Harbor seals are becoming a big problem for salmon, as their populations have been increasing 6-10%, decreasing an already low population of salmon. About 20% of salmon show signs of escaping harbor seals.
Salmon remain in the ocean for 1-7 years to grow and mature. Female salmon mature faster then males. When salmon are ready they come back to their home streams that they were born in to spawn. They know that it’s a good place to spawn which is the reason why they come back to that same stream. They save time trying to find some other stream to spawn in.
In order for salmon to prevent extinction, 2% of young salmon need to survive and at least 6% of those need to return as adults. Salmon make great journeys just to reach their home streams, going 1,000 miles Inland. During this journey they will not eat. They use stored body materials for their energy and developing eggs. The salmon’s appearance changes during these trips. Its color changes, jaw becomes hooked, and develop humps on their backs.
Female salmon prepare their nests, called redds and deposit their eggs; then a male comes and he deposits his sperm. After the salmon have spawned, they will die days later. It takes around 2 months for the eggs to hatch and the cycle continues.
Fish Alaska this summer !!!