"This is cruel!" Katie Arata screams "They're hitting them in the head with a hammer and there's blood everywhere!"
She looks at her teacher earnestly, but the answer comes instead from another classmate, Mia Knipper.
"But they need to do it if they want to have new fish," Knipper explains.
The two seventh graders from Stockton's Waverly Elementary School have just witnessed the gruesome side to the spawning procedure at the Mokelumne River Fish Hatchery, where more than 8,000 salmon came to end their life cycle last year.
It's a necessary process to keep the salmon population and the river healthy.
Through two large windows the students see the sorting area, where they watch salmon move down two metal platforms - one side for the males and one for the females - two workers wait with orange rubber hammers, with which they hit the salmon on the head.
A third worker sprays water through the females' gills to get all the blood out before moving them down to where workers will remove their eggs.
At the end of the two platforms one worker sits with an empty white tub. She slits open a salmon's belly with a knife while another worker picks up a male salmon and squeezes its belly until a white liquid squirts out near its tail.
The white liquid, or milt, the scientific word for salmon sperm, is squirted into the white tub before, and while, the eggs are removed from the female's belly and scooped in.
A little swish of the tub and the workers have the beginnings of up to 5,000 salmon, which will be reared at the hatchery and released in the San Francisco Bay in late April.
John Precissi, the science teacher who took his sixth-, seventhand eighth-grade classes to see the salmon on Monday, said he gets mixed reactions from the children each year, but he finds it important to impress upon them how necessary it is to have the hatchery at the foot of Camanche Dam.
"Sure, it's an eye-opener cruelty-wise, but these fish die anyway so it's important for (the children) to know why its done," Precissi said.
By the end of the tour most onlookers understand the need to artificially spawn the salmon, said Shazana Gardner, the California Department of Fish and Game employee who leads group tours of the fishery hatchery.
"We really try to explain that this is done for the good of the salmon," Gardner said. "It may not be pleasant, but it's a reality of keeping the salmon population strong."
But not everybody agrees.
Some, like Bill Jennings, think hatcheries create fish that don't know how to survive in the wild.
Fish raised in hatcheries may also be more prone to diseases and could lead to a diluted gene pool, said Jennings, the executive director of the California Sportfishing Protection Alliance.
"A hatchery is a poor substitute for the natural cycle," Jennings said. "It breeds dumb fish and truncates the genetic diversity of the fish."
But without the hatchery, the Mokelumne River salmon run may not have survived long past 1964, when the natural spawning habitat was destroyed and Camanche Dam was built.
Results at the hatchery have been promising with numbers increasing from 2,000 total spawning salmon in 1964 to 16,128 returning last year, half of which spawned naturally in the river.
While salmon may not naturally be slit open and milked to reproduce, they do die after they've finished the process. And biologists found more than 2,400 salmon nests in the Mokelumne River last year, meaning at least 5,000 salmon spawned and died in their natural habitat.
Hatchery by the numbers16,128: Total number of fish to return to the Mokelumne River in 2005.
8,187: number of salmon to return to the hatchery in 2005.
5,000: possible number of eggs from one salmon.
506: number of female chinook salmon to enter hatchery this year (as of Nov. 9).
425: number of male chinook salmon to enter hatchery this year (as of Nov. 9).
58: optimum water temperature in degrees fahrenheit for spawning salmon.
15: average weight in pounds of a spawning salmon.
Source: Department of Fish and Game.
Located on McIntyre Road, off Highway 88 in Clements, the fish hatchery is composed of a visitors center, the spawning area with rearing tanks, where the fry, or baby salmon, develop for about six weeks, and 20 or more concrete raceways outside, where the young salmon, also called fingerlings, are raised alongside steelhead, which have a longer spawning period that begins around January.
Gardner said people are sometimes shocked by the spawning process, but are appeased when they see the final result at the end of the tour. The tour finishes at the concrete raceways, where students are able to feed the fingerlings and watch them swim and jump.
Even without the hatchery operation, the salmon would have died said Steve Boyd, an East Bay Municipal Utility District fishery biologist working at the hatchery. He said the hatchery process just allows a larger portion of the population to finish the life cycle than would be possible in the limited habitat.
Boyd said spawning the fish is one of the main tasks at the hatchery, but there are several other important projects taking place within the hatchery.
Workers do research to determine the age of the salmon returning for spawning. They keep track of the salmon population. They track salmon migration patterns. And they manage river flows and temperatures to give salmon an opportunity to spawn in the wild.
In addition, nearly 50,000 pounds of salmon is donated each year to the San Joaquin County Commodities Program, which provides food for the needy.
"I thought it was mean until I knew what they were doing," said Ashlynn Poggio, one of Precissi's seventh graders, "I guess if it helps it's a good thing even though there's a good and a bad side to it."
First published: Tuesday, December 5, 2006