Fishy business: DOW assists Kokanee salmon spawn
summit daily news
GRAND LAKE – Just below Grand Lake, at the Shadow Mountain Reservoir dam, Ed Schlottach roamed between the spawn shack and the egg cleaning tent, donning heavy wool pants and a fur-lined hat with ear flaps flipped up to ward off the freezing temperatures.
As he and other men, mostly from the Colorado Division of Wildlife, set up for Monday’s Kokanee salmon spawn, fish the color of the last rays of sunset moved upstream to lay their eggs and begin the reproduction process.
What the salmon didn’t know – but what the DOW officials and Schlottach did – was that the fish would be herded into the spawn shack and become part of an artificial fertilization process.
Ultimately, the fish swimming upstream would die. Their eggs would be taken immediately to the Glenwood Springs hatchery, where they are incubated and raised through the winter before being released as 2-inch fingerlings back into Lake Granby and other Kokanee salmon-stocked fisheries in the area.
Schlottach, who has been a DOW volunteer for 30 years, was among a host of full-time professionals and seasonal technicians as well as other volunteers who’d assembled to gather the salmon, squeeze out their eggs and sperm and send the new offspring off to be raised in a controlled environment.
After the first seine, the spawn shack was alive with activity. The water rippled as the fish swam around, and as they were netted into an aluminum tub, their tails smacked against each other and against the walls. Men in waders grabbed them and began the process.
“Green! Ripe! Spent! Harvested male! Returned male!”
All are terms to describe the fish and recorded for data collection. A green fish is tossed back and might be harvested later. A salmon that’s ripe is squeezed – her eggs going into a small bin – and tossed into a bucket. So are spent salmon, which are fish that have already laid eggs. A harvested male has had his sperm squeezed to fertilize the eggs in the bin. A returned male goes back to the stream.
It’s a complex procedure. To prevent the spread of invasive species into Colorado’s hatcheries, the fish squeezing is completely separate from the egg washing next door.
Schlottach headed up the latter. Holding a bin of fertilized eggs, he ran it under water pulled and filtered from the stream bed. The water activates the sperm, he said, fertilizing the egg within 90 seconds, but that’s not the end of it. If the batch of eggs has any impurities, such as feces, broken eggs or bacteria, it could ruin it in its entirety. So, Schlottach and his crew focused on the bins, carefully extracting what they could see with the naked eye.
“When you think you’ve got them all out, you don’t,” he said as he instructed one volunteer on how to wash the eggs. Turning to her bin, he added, “and you’ve got a piece of poo-poo in there, too.”
After washing, iodine does the rest as the eggs are deposited into a larger bin headed for the hatchery.
“We need every egg we can get,” Schlottach said. The Shadow Mountain spawn starts in early November each year and goes until the crew has at least 1.2 to 1.3 million eggs. Preferably, they pull more, said DOW aquatic biologist Jon Ewert.
Ewert explained the mortality rate for naturally spawning Kokanee salmon in Colorado is extremely high. In the hatchery, it goes down to about 20 to 30 percent. So, to be able to restock Lake Granby with 1 million Kokanee salmon each year, it’s ideal to have a few more eggs.
If they get more eggs, the additional offspring are placed in other reservoirs, such as Green Mountain Reservoir, where spawns don’t take place, Ewert said.
Monday’s collection put the total egg collection from Lake Granby close to 1.5 million, he said. The goal is 2 million, so several more egg collections will likely take place – until the harvest drops below 100,000.
Kokanee salmon were introduced to Colorado waters in the 1950s as a sport fish.
The Pacific Northwest fish had evolved to die after spawning. Their decomposing bodies would provide nutrients lacking in their stream habitats that are lined with conifers, not deciduous trees. Those nutrients would feed bugs that would in turn feed the fish offspring, said Billy Atkinson, aquatic biologist with the Steamboat Springs DOW office.
“They transfer nutrients from the ocean to their offspring,” he said.
Ewert said it was about a decade after Kokanee salmon’s first Colorado introduction that DOW officials introduced lake trout. They quickly realized they’d created a food chain: Kokanee salmon feed off a type of plankton in the water, and lake trout feed off Kokanee salmon.
But between the Kokanee life cycle and the frigid Colorado river and lake environments and the area’s predators, DOW officials would have to intervene in the spawning process annually.
Atkinson did point out, though, that there’s an active and naturally reproducing population of Kokanee salmon in Dillon Reservoir. The fish swim up the Snake River inlet and have successfully reproduced there for years.
On Monday, about three dozen individuals with fishing licenses waited in line with coolers, trash bags, buckets and more for about two to three hours as the spawning operation took place.
Eventually, they would show their licenses and be handed up fish – sometimes up to a few dozen – to take home. The average giveaway is a few hundred fish, Ewert said.
The egg collection process is completely open to the public, he added, and especially to those holding fishing licenses.
“They foot the bill,” he said, meaning that the fishing licenses pay for the full-time and seasonal labor that makes things such as the Kokanee salmon spawn possible.
Because of that and because the fish naturally die after spawning, they’re handed out when the operation is complete. During the operation, they’re welcome to poke their heads into the spawn shack or the egg washing station, ask questions, and see how it’s done.
SDN reporter Janice Kurbjun can be contacted at (970) 668-4630 or at firstname.lastname@example.org.
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