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Spawning season underway

Pike eggs delivered to hatchery

Ben Oldenburg, Garrison Dam National Fish Hatchery, uses a small vacuum to remove unfertilized northern pike eggs from a hatching jar containing thousands of eggs. The eggs were harvested from Devils Lake pike. Kim Fundingsland/MDN

RIVERDALE – It’s quite a site. More than a million northern pike eggs incubating in jars at the Garrison Dam National Fish Hatchery.

The source of the eggs was Devils Lake, where North Dakota Game and Fish crews had a brief but very outstanding spawning effort.

“We had a nice little pike run this spring,” said Randy Hiltner, NDG&F fisheries biologist. “It was early. We set our first nets on March 29. Usually it’s closer to April 20th.”

It took just three takes of trap nets to produce more eggs than the 160-quart goal.

“We easily surpassed that,” said Hiltner.

That assessment was confirmed at the Garrison Hatchery where 190 quarts of northern pike eggs are in hatchery jars. Earlier this week some of the pike were emerging from their eggs, still carrying their yolk sacs which will be their source of nourishment for about 10 days.

“We have 190 quarts, so that is a lot of extra northern pike fry,” said Jerry Tishmack, Garrison Hatchery.

According to Tishmack, the eye-up rate for this year’s take of pike is 80% or better. That compares to an average expectation of 50-60% eye-up. Eye-up is when the development of the tiny pike in the eggs reaches the stage where the eyes become visible, which indicates the productivity of the eggs.

“Last year we took 115 quarts of eggs and the female pike were about three pounds,” remarked Hiltner. “This year they’ve grown some, a little better average size this year with four to five pounders. You get more eggs per fish that way.”

The largest pike in the nets this year, said Hiltner, measured 47 inches, which would put it at well over 20 pounds. A few other pike in the 40-inch class were netted too. Regardless of size, it is the quality of the eggs that has left an impression on biologists.

“They are good eggs. The Devils Lake eggs have been awesome for the last couple of years, for sure,” said Tishmack.

This year’s request from NDG&F was for 750,000 pike fry. That number is expected to be surpassed quite easily given the number and quality of this year’s eggs. An 80%-plus eye-up on approximately 1.5 million eggs means the potential is there for the hatchery to produce a lot more pike than requested by Game and Fish.

“We’ll put a feeler out there to see if any other states are interested in surplus northern pike fry because when you take 190 quarts of eggs and end up with more than 80% eye-up, you are going to have about 20% extra fry,” stated Tishmack.

The pike will be moved to the hatchery’s outdoor ponds as they reach the final stages of absorbing their yolk sacs and transition to feeding on their own. The hatch rate is controlled in the hatchery by regulating water temperature in the hatching jars, generally from 45 to 52 degrees. The goal is to move the pike outdoors to water of similar temperature.

“We’ll take them straight out of the jars and into the ponds,” explained Tishmack. “They’ll go on food right away. We can actually match the pond temperatures exactly or pretty close.”

The pike will be removed from the ponds when they reach 1 1/4 to 1 1/2 inches in length and transported for stocking into various waters in the state.

“If you leave them in any longer than that they start to eat each other. They are cannibalistic, that’s for sure,” remarked Tishmack.

Northern pike spawn earlier in the year than walleye. Game and Fish crews are expected to begin netting walleye as early as next week. Artificial spawning greatly increases the survival rate of young-of-the-year northern pike and walleye.

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