California Department of Fish and Wildlife

Mad River Fish Hatchery - The Facility

Mad River Fish Ladder. The fish ladder provides a series of pools for the steelhead to jump up on their way back to the hatchery. Six-hundred-fifty gallons per minute of water goes down the fish ladder when it is in operation during the spawning season (generally January to March). There is no fishing within 250 feet either upstream or downstream of the fish ladder.
Image of spawning and egg incubation building. At the top of the fish ladder, fish swim right into the adult holding pond. On spawning days you can see the crowder (the little cart with gate-like structure hanging down into the water) scoot the adult steelhead through a door right into the spawning and egg incubation building.
Fish swimming in dope tank where they are anesthetized. Immediately upon entering the spawning and egg incubation building the fish are anesthetized in the carbon dioxide supersaturated dope tank.
Fish are sorted by CDFW workers. The dope tank raises up from the level of the holding pond up to where they will be sorted.
CDFW worker squeezes fish. The staff squeeze the fish to check the status of the eggs - this requires a great deal of experience.
Image of fish being sorted. Fish that have hard bellies, which means their eggs are not ready, are called green fish. Green fish will be put into the green tub to recover from the anesthesia. After the fish recover they will be dropped down a chute that goes back out to the Mad River.
Workers place ripe fish in blue box. Fish who have soft bellies, which means their eggs are ready to be spawned, are called ripe fish. The ripe fish are put into the blue box. Every fish gets a hole punched in its tail on its first visit.
Air is injected into fish to force eggs out.
Image of worker checking for fish which need to be burped.

Ripe fish will next be taken from the blue box to be spawned. To spawn the steelhead, 3-5 psi of air is injected into the abdomen of the females to force the eggs out.

Because of this method, when the steelhead are placed in the recovery tank they may float and have to be burped to remove air left in their abdomens. To burp the fish, the tail fin is held and gently pressed from the top of the abdomen towards the anal fin/vent until the excess air is removed.

Container of eggs and sperm

During the spawning process the hatchery spawns 1 female and 2 males in the following order: male-female-male. Fertilization takes place in approximately 3 minutes.

Eggs are stirred gently to keep them from sticking together. An iodine solution is used to disinfect water and eggs for 15 minutes. This removes any impurities that may have been introduced during the spawning procedure from humans or, male or female fish. Eggs, at this stage, are soft, absorbing water and getting larger. Eggs are left in water for 2-3 hours, then counted.

Egg trays in the spawing and incubation building Next the fertilized eggs are put into trays in the spawning and egg incubation building that have water flowing from above onto them and let the water flow out the bottom. There are 16 trays stacked on each other in each stack and 48 stacks total at the hatchery. Each tray can hold 30 ounces of eggs. Steelhead eggs generally have 200 eggs in each ounce, so each tray can hold approximately 400 eggs.
Eyed fish eggs

Eyed eggs are more stable and can handle being moved. This is the stage at which classes receive eggs for their incubators. Once the eggs become alevin, they will also live in the trays.

As the eggs continue to grow, some may die. These dead eggs will turn a whitish color and will start to grow fungus. The hatchery must dispose of these, as they can infect other eggs. The warmer the water temperature the quicker the eggs hatch and the colder the temperature the slower they hatch. Normal water temperature for eggs ranges between 48-52 degrees Fahrenheit.

alevin with visible egg sacks still attached As the eggs develop they go through several stages. From day 1-3 they go through the green stage. They are undergoing mitotic cell division and are especially fragile. From day 3-15 the eggs are in the tender stage and any moving may shock the eggs leading to their death. The eggs become eyed eggs from day 16-40.
fry Fish will be ready to move to troughs within the spawning and egg incubation building starting around March when they have become fry. The fry will begin eating 2% of their body weight per day and approximately 4x/day. The fish food contains herring, cotton-seed, wheat kelp, tuna viscera, crab meal, and vitamin supplements. At approximately 3 months, the fry are moved outside into the raceways.
View of Mad River Raceway.

Raceways are made up of 6 connected cement ponds with each pond being 100 ft long, the raceways are 600 ft long in total. There are 10 raceways at the Mad River Fish Hatchery but currently only two are being used to raise steelhead. The water recirculates through the raceways through a system of flumes and pumps.

While outside in the raceways, the steelhead are vulnerable to predators like osprey, raccoons, kingfishers, herons and egrets. Overhead wires are strung above the raceways to control birds, but some birds, like Osprey can dive through the wires by holding in one position above the wires to gauge the space and then descending into the raceways. They pick out fish, and fly out the side.

Close up view of raceway.

The steelhead are raised at the hatchery for approximately one year, and released in March or April. In the wild, steelhead stay for 1 year or more in the streams and estuary. All of the fish are returned to the river. Before they are released they will have their adipose fin clipped off to mark them as hatchery fish. Outside the hatchery building is a small shed used for clipping fish before release.

There are two flumes at the end of the raceways. The deeper flume is not currently in use. The shallow flume supplies water to the recirculating and fish ladder pumps.

Ultra violet light buildings used to kill micro organisms that build up in water At the top of each raceway is an ultra violet (UV) light building that kills micro organisms that build up in the water while it recirculates through the raceways. The UV tubes can cause blindness in minutes and retinal burns in 2 minutes or less so they are kept out of sight in the buildings. There is a separate UV light in the spawning and egg incubation building that filters the water there.
Filter ponds being viewed by school group The past few years the filter beds are only being used to move water through to the settling ponds near the river. In the past the filter beds were full of 4 ft of oysters and 4 ft of water. The convoluted surfaces of the oyster shells trapped microorganisms that cleaned water. Now the water is filtered as it settles through the substrate of the setting ponds back to the river.

More Hatchery Terms

Well fields
The hatchery uses water from 18 wells that are on the property. Currently, only 4 are in, operation. Each well is 150’ – 250’ deep.
Generator building
The generator operates wells and pumps in case of a power failure. Diesel tanks hold 1,000 gallons and use 14 gal per hour providing back up power for 71 hours or 3 days.
The aerator replaces oxygen in the water that was removed by the fish in the raceways. The aerator can pump 6 cubic feet per second or 2,500 gals/minute. Currently the hatchery does not need this much water but this is how much water is needed to keep the water flowing from the aerator to the top of the raceways.
The weir was used when salmon were raised at the hatchery to block the salmon from continuing upstream and guiding them into the fish ladder up to the hatchery. The hatchery is not currently using the weir because the steelhead are so attracted to the well water they were born in that is coming down the fish ladder they come back to the hatchery on their own. Although the gate-like panels are removed you can still see the wave created by the cement base in the winter and the cement base itself in the summer.