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By DANELLE LANDIS
Daily News Staff Writer
Elizabeth Avila’s third-grade class flowed into the Deer Mountain Hatchery near City park early on this past chilly, damp Thursday morning. The Ketchikan Charter School students chatted and fidgeted in the bare entry room that smelled faintly of salt water and disinfectant.
Hatchery Manager Matt Allen greeted the students, and outlined the morning’s agenda.
“What we’re going to do today, is we’re going to give you an opportunity to look at some coho that came from Whitman Lake out at Herring cove. This is about the time of year that we’re spawning them, so we’re going to take you through some basic fish anatomy, we’re going to do spawning demonstrations, and then if you guys would like, we’ll have the opportunity to feed some of the chinook we have out here in the raceway,” he said.
He invited questions, and Ezekiel Avina’s hand shot up.
“Why do you keep the fish here?” Ezekiel asked.
“The hatchery’s a good place to take care of them when they’re young,” Allen said. He further explained that the young fish in a hatchery are protected from predators, and can be fed in a way that gives them the heft and strength that will benefit them as they mature.
Nayomi Vassas, who asked if the hatchery had smoked salmon, was disappointed to hear from Allen that none of the hatchery’s fish come in a snackable form.
The group then moved to a covered area near the net-covered fish pens, swirling with tiny salmon. Voices rose with excitement as they approached a table with two adult coho salmon, a female and a male, lying side by side. Inches away, a little aquarium held two-month-old king salmon in alevin form, their skinny bodies and bulging yolk sacs giving them an alien appearance.
Allen had prepared the adult coho salmon for the students’ viewing by cutting the fish open to reveal their body cavities and removing the gill plates to expose the gills. The salmon’s organs, including skeins packed full of orange-pink eggs, were lying next to them in the order they would appear in the gut.
The students pressed forward to examine the parts, gently stroking them.
“Can anyone guess about how many eggs a female coho might have?” Allen asked.
The first guess was 100. The second guess was 3,000.
“3,000, that’s actually pretty close,” Allen said. “On average, they have about 3,500 eggs.”
He added that sometimes the number of eggs can depend on the size of the fish.
Allen walked them through the salmon’s anatomy, and the children quieted as they listened.
“This is the gill plate, or operculum,” he said, replacing it over the gills. “The gills are simply the fish’s lungs. And, you can see, without this gill plate, the lungs would be exposed and they might get damaged.”
He continued, showing them the heart, pyloric caeca, esophagus, stomach, intestines, kidney and air bladder.
Allen fielded a question about the long, bloated air bladder.
“Normally, this organ would be right up along the top of the backbone here,” he said, stroking the underside of the fish’s spine. “It acts just like a life preserver,” he said. “It allows those fish to navigate up and down the water column, so if it wants to be up at the surface, this would be filled with air. If it wants to go and swim deep, the air would leave this bladder, and the fish would be able to go into deeper water.”
He then guided them through the external anatomy, pointing out the male’s larger size, redder color, hooked jaw and larger teeth. He said the female’s belly tends to be more rounded, as her eggs mature.
He pointed to and named each fin, describing the function of each and explained the purpose of the hatchery’s practice of marking tagged salmon by cutting off the adipose fin before release. When that fin is missing, fishermen know the salmon has had a metal coded tag implanted in the snout when they were juveniles at the hatchery.
The tags in commercially caught fish are tracked at fish processing locations by Alaska Department of Fish & Game employees. When sport fisherman catch salmon, they can submit the heads for scanning, Southern Southeast Regional Aquaculture Association General Manager David Landis said by phone.
Allen explained, “That allows us to evaluate our programs; it allows us to know where that fish came from, when it was released.”.
The Deer Mountain hatchery is one of seven run by the nonprofit SSRAA.
Lauralye Boor was curious about another organ that hadn’t been laid out for view.
“Does the female and the male have a brain?” she asked.
Allen assured them that they both indeed, do have brains.
“Do you want to see the brain?” Allen asked.
“Yeah!” agreed a raucous chorus of kids.
Their teacher, Avila, laughed and explained they’d recently studied the spelling word “zombie,” and that had sparked their high interest in brains — or in the case of zombie behavior — the undead’s appetite for them.
Fish culturist Michelle Leitz led the next demonstration with two more coho salmon laid out on a tarp on the concrete floor near the table.
Leitz began by brushing an iodine solution over the two salmon, also a male and a female.
“It’ll just keep anything that’s on their body out of the eggs that might cause disease,” Leitz told the students.
She then picked the female coho up by the head, belly toward the students, over a clean plastic tub. She held up a small, plastic-handled hooked knife to the fish’s vent, at the bottom of the fish’s abdomen.
“I’m going to put this knife in the vent so the eggs don’t fall out and I don’t lose a bunch, and I have to pull the knife around those fins,” she explained.
She then slit the fish’s belly and eggs poured out. The children gasped, giggled and exclaimed as the eggs fell into the tub.
Leitz’s next step was to express the male’s sperm-filled milt over the puddle of eggs, simply by squeezing his middle.
“Sometimes we’ll use two males, so that way, you get some genetic diversity,” Leitz said as she laid the male fish down then began to stir the milt into the eggs.
The mixture began to bubble slightly.
“They start getting excited and they foam up,” Leitz said, laughing.
She poured the fertilized eggs into a tray and gently spread them out.
“This tray gets put in an incubator that also has an iodine solution in there — kept in there with the water off for one hour,” she said. “That makes sure that any disease that’s on the outside of the eggs gets washed off.”
When the hour is up, the water is turned on, Leitz said, then told the students that the fragile eggs are not touched again until an eye can be seen inside. At that time, they’re quite resilient.
“Then, they’re really strong. They almost bounce like a ball,” Leitz said.
She said when the developing eggs show enough maturity, the culturists shock them by bouncing them against a hard surface. That makes the non-viable eggs turn white, and the culturists can pick them out before they “turn fungus-y” and damage the other embryos.
Allen brought a little netful of eyed eggs out for the students to hold and study. The students exclaimed over the shiny eyes peering out of the plump globes as they gingerly balanced them in their palms.
“They’re cute,” Logan Grissom declared, as he examined the eyed egg on his palm.
The last project for the field trip was to toss the brown pellet feed into the churning king salmon fry tanks alongside the walkways near the covered area. The children laughed and chatted while the fish flipped and spun to catch the bits they scooped from their paper cups.
Back in the entry room, there were a few more questions.
“Did this place ever hold any other salmon besides king salmon?” Kyle Peterson asked Allen.
“In the past, they’ve done summer coho,” Allen answered, “they’ve done steelhead, which is a rainbow trout that lives in saltwater. They’ve done multiple species.”
James Iverson asked why the hatchery raises so many fish.
“Part of the reason we raise a half a million is because the vast majority probably get eaten or predated upon by something that likes to eat salmon,” Allen answered.
He then asked the students to offer their ideas of what animals might eat salmon, and the kids tossed out their ideas, which included bears, eagles, squid, octopus, sharks and whales.
“How long do they live?” Amanda Sivertsen asked.
“The coho that you saw, that we spawned today, they were taken as eggs three years ago. So, they basically only go out in the ocean for about a year and a half before they come back,” Allen said. He added, “Now, king salmon are different. King salmon might spend two, three, four or five years in the ocean. That’s why they get larger”
Ezekiel Avina raised his hand for one last turn to talk to Allen.
“Thank you for teaching us about the salmon,” he said as he joined his classmates to line up for the walk back to their school.