Commercial, sport and pirate fisherman stress our fisheries. New fishing techniques are wiping out entire schools of fish, leaving them unable to reproduce. In response to such over-fishing, hatcheries are responsible for the release of five billion salmon in the North Pacific Ocean, yearly.
Invasive fish species have been released around the world intentionally, carelessly and optimistically. Invasive species are responsible for the destruction of fauna and the extinction of native fish.
Hydro-powered dams affect migration patterns and spawning. Fish ladders are largely unsuccessful at allowing fish to pass through. Dams change seasonal water flow as well as natural water temperatures.
The creation of dams and reservoirs force fish to compete with man for water.
Hatcheries began opening their flood gates over a hundred years ago in North America to aid decreasing fish runs.
Constructed in 1909, Bonneville Hatchery is ODFWÕs largest hatchery facility. Today, it operates harvest and conservation programs. More than 26 Oregon hatcheries are responsible for releasing roughly 45 million salmon each year.
Oregon Department of Fish and Wildlife personnel corralled the remaining coho salmon to finish off the spawning season. Fish exit the rivers through fish ladders, which lead to holding tanks, where they are held between one to three months before they are spawned.
An electronic crowder pushes the fish towards the elevator leading them to the spawning room.
Members of the ODFW work at hatcheries year-round, regardless the season.
Just a few drops of extracted Coho semen can fertilize a few thousand eggs. At the Bonneville Hatchery, one male is paired with two females.
Before the eggs are extracted, the fish are bled to death.
Diseases can be devastating to hatcheries and wild populations. Kidney samples are taken from all the fish eggs collected. If the lab results are positive for disease, then the eggs are terminated.
A variety of tools are needed tools to clean tanks and transfer fish.
Egg development is calculated in thermal units. The temperature of the water is monitored and regulated to speed up or slow down the development.
After the yolk sack is completely absorbed, the fish are then transferred to larger tanks. Depending on the intended purpose of rearing, the fish may spend anywhere from a month to a year and a half at the hatchery.
Once inseminated and the eyes have developed, they are shocked, dropped a short distance, to eliminate the weak from the healthy eggs.
The fish are fed daily rations to meet growth expectations. Some facilities feed the fish by hand and others use electronic feeders.
The Oregon Research Hatchery Center located in Alsea is responsible for carrying out experiments to learn how to improve hatchery procedures. They designed three artificial rivers with cameras underwater to conduct experiments about fish behavior.
Radio frequency identification device tags allow researches to track fish. RFID readers are placed along rivers and dams to monitor migration patterns.
Fish are released at different sizes depending on the species and purpose of rearing. If they do not swim out the same fish ladder their parents came in from, they are put on trucks and transferred.
