California G&F tests Lake Davis explosives

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Calif. Game Officials Set Fish Bomb

Apr 24, 2002

Employees of the California Department of Fish and Game, troll Lake Davis, near Portola, Calif., looking for dead fish after explosives were used in a test to eradicate the northern pike, Wednesday, April 24, 2002. The non native fish had been illegaly released in the lake in the late 90's and officials fear the fish will go downstream and endanger native fish.(AP Photo/Rich Pedroncelli, Pool)

PORTOLA, Calif. (AP) - State Fish and Game officials detonated explosive cord in a Sierra Nevada lake Wednesday to see if such explosions will kill northern pike without harming other fish or the environment.

The voracious pike are eating trout in Lake Davis, and state wildlife officials have engaged in a multimillion dollar, multiyear campaign to control the fast-breeding species.

The state hopes to prevent pike from escaping into California rivers, where they could feast on endangered salmon. It's spending about $500,000 a year on control efforts, including about $200,000 on the explosions.

Wednesday's explosion killed all but the most distant of about 25 fish placed in nets at various distances from the detonation cord, as expected. Divers also collected dead fish, but weren't finding many, said Department of Fish and Game spokesman Steve Martarano.

The point of the experiment wasn't so much to kill fish as to measure whether the explosives stirred up sediment, created air pollution, or disturbed wildlife, Martarano said.

The department now plans to blow up 10 acres at a time, as many as 15 more times over the next two years, aiming for the shallows where the pike breed and grow.

In 1997, the department dumped 50,000 pounds of the chemical rotenone into the lake, but the poisoning failed to eradicate pike. The poisoning prompted public outcry and cost $2 million, plus an eventual $9.2 million in reparations to residents.

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On the Net:

Department of Fish and Game: http://www.dfg.ca.gov/northernpike/index.html

 

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California tests explosive solution to pike problem

Mark Henckel, Billings Gazette

4/28/02

Fishermen used to joke about using the old, reliable "DuPont Spinner" - dynamite - if they really wanted to take out a bunch of fish.

That's illegal, of course.

But it's exactly the strategy that the California Department of Fish and Game (CFG) used last week on Lake Davis, a popular Sierra Nevada trout fishing destination where an illegal introduction of northern pike has created a nettlesome problem.

CFG set off 1,000 feet of detonation cord - a pencil-thick cord holding polypropylene-and-cellulose-wrapped explosives - in a one-acre cove of Lake Davis called Mosquito Slough last Wednesday. The agency was testing how the explosive might work in larger applications in the future to contain and control pike numbers.

Word of the test came by way of e-mail from Steve Martarano, an information officer with California Fish and Game, who noted the story in last Sunday's Billings Gazette on the netting operation trying to remove illegally introduced northern pike from Western Montana's Milltown Dam.

Northern pike were illegally introduced in Lake Davis sometime in the early 1990s. It currently is the only known northern pike population in California, Martarano said in a telephone interview.

"It was just a test shot. It didn't get that many pike," Martarano said. "This really isn't the prime time to be doing it. That would be during the spawn and that is only a 10-day window and it was about three weeks ago."

CFG had used detonation cord in the past, including a shot on the Eel River in the mid-1990s to try to get rid of non-native species. "We know it's an effective way to kill fish," he said.

Going the detonation cord route became an option after what can only be described as a nightmarish episode between CFG and local residents with more traditional rotenone poisoning of Lake Davis in 1997.

CFG dumped thousands of gallons of rotenone in the lake that year, toxins leaked downstream into the San Joaquin drainage, lake water was said to be tainted for months, including an area town's drinking water supply. Some residents got sick.

The poisoning apparently still didn't take out all the pike. They showed up again in 1999. In 2000, CFG crews removed 600. Last year, through electrofishing, netting and seining, they removed 6,300 more.

CFG created a steering committee to look at other options for pike removal, which led to the detonation cord experiment last week.

"Our aim this time wasn't to kill a lot of fish. It was a test shot of only 1,000 feet covering an acre, and next year we plan on doing six shots of 10 acres each, and those will be designed to kill a lot of fish," Martarano said.

"We wanted to get a lot of the environmental review stuff out of the way. This shot didn't seem to get many fish at all - trout or pike. We set up about 25 pike and other fish in 12 cages, or cars, at different intervals away from the detonation cord to see how effective it was, and all but one about 34 feet away died in the blast."

As to the blast itself, a press report in the Sacramento Bee recorded that it wasn't really much of a show. It was described as "a quick linear splash, that was akin to whipping a garden hose in a pool."

It was all over in a matter of seconds.

Martarano added, "There was a bald eagle's nest nearby and we wired it for sound. Setting the detonation cord off had no effect. Water quality was also being tested."

Plans for future use of the detonation cord are to monitor its nontarget effects on trout and to replant two trout for each one that is killed by the cord.

"Control and contain the northern pike is what we're doing," Martarano said. "Our goal is to keep the lake as a viable trout fishery and to keep the northern pike from going down the San Joaquin delta system and watershed."

He added that in addition to future plans to use more detonation cord, other control techniques will also continue - electrofishing, netting, seining - in an attempt to keep the northern pike population in check and reduce their numbers.

As to the effectiveness of these methods in keeping the pike population in check, no one can predict how that might play out.

How do others view the northern pike situation in a trout water like Lake Davis? Check this out. In a Sports Illustrated Adventures report sent to subscribers last week headlined "Invasion of the Trout-snatchers", writer Austin Murphy started his story on the Lake Davis detonation cord experiment this way:

"If Hell has a lake, you know what it's stocked with. We're talking here about a fish that only its mother - and PETA - could love. The northern pike is a homely, slimy, saw-toothed predator. It is also as resilient as Aerosmith, which explains the concussive thuds emanating from beneath the surface of Lake Davis this week...."

A bit overstated? No doubt! But it's a prime example of how polarized the situation can be over pike in trout waters. And the California experiment on using detonation cord might provide another weapon in the arsenal for controlling, containing or possibly even eliminating unwanted fish populations.


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Mark Henckel is the outdoor editor of The Billings Gazette. His columns appear Thursdays and Sundays. He can be contacted by phone at: (406) 657-1395, or by e-mail at: henckel@billingsgazette.com