Invasive species are a curse to people who value native fish and wildlife.
But some people consider exotics a prize in their backyard.
Professionals who manage public lands, waters, fish and wildlife have to deal with both groups, as well as with the invasive weeds and predators. That’s a tough job.
Topics ranging from angling to zebra mussels were highlighted Tuesday at the Davenport Hotel during an invasive species session at the Lake Roosevelt Forum, an annual gathering of Columbia River Basin scientists and policy makers.
They talked about milfoil and rock snot as well as walleye management in Lake Roosevelt.
The most potent issue this spring is the hammer dropping on the northern pike in the Pend Oreille River upstream from Roosevelt.
Northern pike are being gillnetted by the thousands on the Pend Oreille. State and tribal fish managers are trying to control illegally introduced pike numbers and curb their downstream spread into Columbia River salmon and steelhead habitats.
Jason Connor, the Kalispel Tribe’s biologist coordinating pike research on the river since 2005, said he’s aware the pike boom attracted new interest in the river, boosting the local economy.
About 4,000 angler hours were devoted to fishing the Pend Oreille River in the 1990s, he said. After pike numbers started mushrooming in 2006, the angler hours spiked to more than 70,000 in 2010, according to tribal surveys.
But the pike already are showing signs of overpopulating and stunting, he said, and risks to native fisheries are serious.
Pike fishing enthusiasts are highly critical of the pike control effort. Non-native pike have found ideal habitat in much of the 55-mile reservoir behind Box Canyon Dam. Meanwhile, the Pend Oreille River encumbered by five hydropower dams in the U.S. and Canada is no longer prime habitat for native trout species such as cutthroat or bull trout.
So the pike anglers ask: Why is the federal government pouring millions of dollars through the Tribes and state agencies to kill pike and promote trout?
Even with the dams, Connor answers, the Pend Oreille River is an important migratory corridor, especially for bull trout. Habitat improvements in tributaries and plans to provide fish passage at Albeni Falls Dam are setting the stage for improving spawning activity in trout coming and going from Lake Pend Oreille.
Gillnetting underway in Box Canyon is attempting to reduce the northern pike population by 87 percent, or about 5,700 pike. The fish are being rendered to fertilizer, since studies indicate the mercury levels in the larger fish MIGHT be a health issue if distributed at food banks.
Through April 7, the 12-20 nets set each day since March 19 had caught 3,019 pike. The bycatch of the river’s other 18 species was 3,913 for the same period.
Early on, the netting ratio was four northern pike for every one non-target species. But the bycatch spiked in April as yellow perch began moving to spawn in the same sloughs where nets were targeting pike.
The bycatch included 2,290 yellow perch, 494 black crappie, 433 pumpkinseed, 258 tench, 182 brown bullhead, 107 peamouth and 90 largemouth bass.
Catches of other species were insignificant, including just two smallmouth bass. The nets are positioned to target pike bound for spawning, Connor emphasized. Different sampling techniques are used to estimate relative population numbers of the different species.
Connor said 90 percent of the perch survived being removed and released from the nets, although he said the survival rate will drop as water temperatures get warmer.
“I can tell you this with absolute certainty,” he said. “The numbers of bycatch we have killed to date pales in comparison to the number that would have been consumed by the 4,000 northern pike that we’ve removed.”
Biggest news: The largest fish fisheries workers have recorded from the Pend Oreille River gillnets this spring is an egg-laden northern pike weighing 38 pounds taken in Tacoma Slough.
The Washington record for the species is 34.06 pounds.
Pike tourney results: The 26 anglers out for the Pend Oreille River Pike Spring Fling tournament last weekend caught only three northern pike on Saturday, reports Douglas Wood of Muskies, Inc. The fish were 22-23 inches long.
Water temps were up to 47 degrees in the sloughs and 40-42 in the river. “Conditions weren’t great, but it was slow,” Wood said.
Cutthroat cabin for rent: A prize crash pad on the North Fork of the Coeur d’Alene River has become available for rental reservations this week.
Avery Creek Cabin is near the blue-ribbon cutthroat stream 20 miles upstream from Interstate 90 at Kingston.
The cabin’s rental season runs May 18-Nov. 18. But reservations can be made now at www.reserveusa.com.