Life Cycle of the Salmon

Life Cycle of Salmon

Salmon are one of the few fish species which can live in salt and freshwater. They spend their juvenile lives in rivers, then migrate to the sea and return later to the place they were born. - The migration to the spawning habitat may commence up to a year before spawning takes place in autumn or winter. The salmon ceases to feed to direct all their energy to reproduction. The fertilized eggs are covered with gravel to a depth of several centimeters by the female. The parents then leave the eggs in the nest, and there is no further parental care. The eggs will hatch after about 180 days at normal water temperatures in March or April.

The just-hatched fish, and still have a yolk sac attached to their bodies containing the remains of food supplied from the egg. When most of their yolk sac has been consumed, the fish become active and begin their journey up through the gravel.

This critical period exposes the young to dangerous predators for the first time. They will remember the stream and will return to spawn as their parents did and eventually die.

Russian River Restoration

The population of Coho in the Russian River was down to, from 100 fish, to a population of about 10. NOAA's involved in various restoration projects throughout the Russian River and the types of projects that we're involved in are fish passage, habitat restoration for in-stream complexity, riparian projects to reduce temperature, erosion control, and projects to reduce streamflow velocity. The flows are elevated seven times above the natural flow level on the main stem Russian River. And the flows in Dry Creek are also elevated because of the releases out of Warm Springs Dam to supply water supply to nearly half a million people in Marin and Sonoma counties. The demand for water can spread the flows with projects like these to reduce the velocities, which is important because that creates the ideal rearing habitat for Coho salmon.

The stream right now is running at about 200 cubic feet per second. When there are winter floods at the damn and the fish need to get out of the way of that high water the flow goes up to 3,000 or 4,000 cubic feet per second. That fills this channel behind, it's actually designed to backwater, so it fills from the downstream end up, so fish can enter, hold there when the flow is really high, and as the water recedes, they swim out without getting trapped. These habitat improvements will increase the number of fishes in the stream. Small tags are implanted in juvenile fish when they're at the hatchery or they're collected in the wild. This backwater channel has two antennas in it, those antennas just look like a loop of PVC pipe, they're designed to detect the fish that carry these small tags as they enter these habitat features in the winter time. Data are collected to when those fish that have been tagged are out in the main part of Dry Creek are coming and going from these habitat features. Data collection during the winter at Quivira, had hundreds of detections of fish coming and going from this habitat feature and they stay in it during these high flood events for up to a week at a time. So, it's an early indication that the fish are detecting and using these places There are Steelhead and Coho salmon that have been detected coming and going from this habitat feature so early indications are that it's working.