05-28-2003, 06:19 AM
Update: California Reconsiders Pike-Killing Explosions
SACRAMENTO, CA--Disappointed with their attempts to kill non-native pike in northern California's Lake Davis, state wildlife officials say they're considering ending experiments with explosives.
The announcement comes after officials set off four miles of detonation cord around Lake Davis in March, intending to kill spawning northern pike. But only four pike and eight trout were recovered after the blast.
The results mirror those of a 1-acre explosion a year ago, which killed only pike that had been pre-positioned in nets at varying distances from the explosive cord.
Despite the poor results, wildlife officials say they aren't completely ruling out another blast. If the explosive option still receives support during a meeting next month to plan future eradication efforts, future explosions might be used.
The rethinking is based on a new mathematical computer model that shows most of the state's efforts have been aimed at the wrong size of the fast-breeding pike.
Since the pike were discovered in Lake Davis in 1994, they've been poisoned, shocked, netted, trapped and hooked -- and the population has thrived. Officials fear they may one day escape from the lake near Portola and devastate other fisheries including the state's threatened wild salmon population.
Full-time crews sent to the lake each summer have pulled out nearly 25,000 fish the last three years, but have been targeting and catching mostly young pike.
To make much difference, they would need to kill large numbers of the older, larger pike that produce the most eggs, according to the computer model used by University of California, Davis ecology professor Ted Foin and graduate student Renee Spenst.
The model predicts the pike population will continue its explosive growth for the foreseeable future, that current efforts won't stop it, and that escape from the lake is inevitable sooner rather than later unless something else is done.
The explosives had been aimed at killing the pike that migrate to shallow areas of the lake to spawn, but higher water levels this year made the shock wave less effective.
Wildlife officials never believed the series of annual explosions alone would significantly trim the pike breeding population.
Rather, they offered it as one more tool in their chest as they try to contain the population until they can come up with a permanent solution. Original plans had called for blowing up 10 acres at a time in the 4,000-acre lake, as many as 15 more times this year and next.
Now the department is working with the community trying to find a long-term solution as it updates the 2000 plan, while stocking the lake regularly with trout to aid the local tourism industry.
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SACRAMENTO, CA--Disappointed with their attempts to kill non-native pike in northern California's Lake Davis, state wildlife officials say they're considering ending experiments with explosives.
The announcement comes after officials set off four miles of detonation cord around Lake Davis in March, intending to kill spawning northern pike. But only four pike and eight trout were recovered after the blast.
The results mirror those of a 1-acre explosion a year ago, which killed only pike that had been pre-positioned in nets at varying distances from the explosive cord.
Despite the poor results, wildlife officials say they aren't completely ruling out another blast. If the explosive option still receives support during a meeting next month to plan future eradication efforts, future explosions might be used.
The rethinking is based on a new mathematical computer model that shows most of the state's efforts have been aimed at the wrong size of the fast-breeding pike.
Since the pike were discovered in Lake Davis in 1994, they've been poisoned, shocked, netted, trapped and hooked -- and the population has thrived. Officials fear they may one day escape from the lake near Portola and devastate other fisheries including the state's threatened wild salmon population.
Full-time crews sent to the lake each summer have pulled out nearly 25,000 fish the last three years, but have been targeting and catching mostly young pike.
To make much difference, they would need to kill large numbers of the older, larger pike that produce the most eggs, according to the computer model used by University of California, Davis ecology professor Ted Foin and graduate student Renee Spenst.
The model predicts the pike population will continue its explosive growth for the foreseeable future, that current efforts won't stop it, and that escape from the lake is inevitable sooner rather than later unless something else is done.
The explosives had been aimed at killing the pike that migrate to shallow areas of the lake to spawn, but higher water levels this year made the shock wave less effective.
Wildlife officials never believed the series of annual explosions alone would significantly trim the pike breeding population.
Rather, they offered it as one more tool in their chest as they try to contain the population until they can come up with a permanent solution. Original plans had called for blowing up 10 acres at a time in the 4,000-acre lake, as many as 15 more times this year and next.
Now the department is working with the community trying to find a long-term solution as it updates the 2000 plan, while stocking the lake regularly with trout to aid the local tourism industry.
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