Mosquito spraying and fish kill are likely unrelated, state says
LEICESTER — A fish die-off in Fern Lake earlier this month has gotten some publicity thanks to one resident’s theory that mosquito pesticide is to blame, but there is no proof of that, yet.
State and local agriculture, fish and wildlife, and mosquito control officials believe the June 4 die-off of several different species of fish in Fern Lake was caused by unusually warm spring weather.
According to the National Weather Service and the Vermont Department of Fish and Wildlife, temperatures were in the upper 80s and low 90s on May 30 and 31 and June 1. Oxygen levels plummet in shallow water of five feet or less in those conditions, and if the warm-up occurs during the spawn when fish are more vulnerable, these conditions can sometimes lead to a die-off of fish, most likely crappie and bluegill.
Fern Lake resident Zachary Saxe told Vermont Fish & Wildlife Fisheries Biologist Shawn Good that he started noticing dead or dying fish June 1-2. Saxe lives year-round in the shallow north end of the lake, but reported seeing dozens of largemouth bass and smallmouth bass, rock bass, yellow perch, bluegill, pumpkinseed, crappie and bullhead all around the lake’s island while swimming on those days.
“The fish kill was in the whole lake,” he said in Tuesday interview. “(Officials) are saying it was the north end, but it was the whole lake. With the wind and the current, the fish ended up in the north end.”
Saxe is well known to local mosquito control officials as being against spraying mosquito insecticides. He has put up signs on his property that say “No Mosquito Spraying.” The Brandon Leicester Salisbury Goshen Mosquito Control District, known as the BLSG, has honored his verbal request not to spray pesticide near his property over the last several years. Saxe maintains, however, that the BLSG continues to spray very close to his property. He also believes that one of the BLSG spray truck drivers lives near him.
“I’m nervous that they overspray this area,” he said. “There is a lot of room for human error.”
The BLSG did spray in the Fern Lake area on May 23 and June 1. While Fish and Wildlife Fisheries Scientist Chet Mackenzie maintains there is no road near the lake where the fish kill was reported, Saxe said that is untrue.
“How do you think people get to all those camps down there,” he asked.
Mackenzie surveyed the Fern Lake shoreline in a small boat on June 5. He reported seeing only one dead fish during the trip. Mackenzie also spoke to two landowners at the southern end of the lake and said they had not seen any dead fish over the previous weekend.
“The northern bays are very shallow and water temperatures are likely to rise quickly when air temperatures are in the 90s and it is sunny,” Mackenzie wrote in an email. “There were numerous spawning beds of panfish and bass throughout the area. I suspect this was a small localized fish die-off due to rapidly rising water temperatures and spawning stress.”
But Saxe continues to question the BLSG’s use of pesticide and theorizes a possible link to the fish kill, despite any scientific evidence of that fact. Media outlets around the state picked up the story last week, including Vermont Public Radio, VT Digger.com, and WCAX television news.
Saxe charges that the state erred in not responding to the fish kill report sooner and more comprehensively.
“Those guys (state and BLSG officials) want to make it sound like it’s no big deal,” Saxe said. “You’re right, there is no proof they killed the fish with pesticide, and the state dropped the ball on that.”
The BLSG suspended mosquito spraying for a day during the investigation, much to the chagrin of many other homeowners around Fern Lake.
And adding fuel to the fire is an erroneous email from Richard Levey, an environmental scientist with the Watershed Management Division of the Vermont Department of Environmental Conservation (DEC). In attempting to calculate the concentration of the pesticide Malathion used by the BLSG, Levy’s math was off. While Malathion is highly toxic to aquatic life, fish and invertebrates, Levey apparently theorized not only the amount of the pesticide used by the BLSG, but the length of the spray and the proximity to the lake. His estimated concentrations vacillated from parts per billion to parts per million and were not based on actual amounts. A reporter for VT Digger used Levey’s erroneous calculations in its June 20 news article on the fish kill. The calculations were also sent out to Vermont Agency of Agriculture Agrichemical Management Section Chief Cary Giguere, Mackenzie and BLSG Chair Gary Meffe of Brandon.
Reached by phone on Monday, Giguere dismissed Levey’s calculations outright.
“It’s all wrong,” he said of the email. “(Levey) used some information from our previous report, but I need him to send out another email correcting the information. He did those calculations and sent it out to everybody before checking the math. The orders of magnitude are way off.”
Giguere also had nothing but a positive view of the work done by BLSG, which he said has maintained a high level of responsible practices and procedures when applying pesticides for years.
“The folks in the district are pretty professional,” Giguere said. “They rotate using different pesticides to help with resistance management.”
Meffe is a conservation biologist and former editor of the scientific Journal of Conservation Biology. He is the author of several textbooks on conservation biology and ecosystem management, and has written more than 80 scientific articles.
The BLSG is funded through taxpayer dollars collected annually in each member town and is a line item in each town’s budget. Meffe said the BLSG is doing what it has been charged to do — control the nuisance mosquito population in the area using best practices, a charge now heightened with last year’s two fatal cases of mosquito-borne Eastern equine encephalitis and the ongoing issue of West Nile Virus.
Unfortunately, Giguere said, the fish kill coincided with a time where Malathion was being applied, and anyone with qualms about pesticides can find plenty of negative information about the pesticide if it is not used properly.
“Unfortunately, this happened on a year when an older chemical product was being used that you can find all bad things about on the Internet,” he said.
Giguere stressed that the Agency of Agriculture is the lead agency for pesticide control in the state and his report is based on Mackenzie’s eyewitness assessment and subsequent report from Fern Lake that the die-off was due to low oxygenation levels.
“We use professional interpretations,” he said. “The Fish and Wildlife report closed my case. That said, there is a lot of interest in finding out what happened.”
Giguere said his office will take water samples from Fern Lake in the coming weeks and the sampling will be coordinated around a BLSG pesticide spraying event to determine just how much, if any, pesticide is reaching the water.
In the meantime, Gary Meffe of the BLSG met with DEC officials on Monday to discuss the parameters of the group’s National Pollution Discharge Elimination System permit. As of 2006 under the federal Clean Water Act, any pesticide application over or near water requires such a permit.
The BLSG has been operating under the guidelines of the permit, but was not aware that it is required to report any adverse effect of pesticide application to the DEC.
“We notified Fish and Wildlife,” Meffe said. “This requirement came out last year, so now we know.”
Saxe maintains that the BLSG practices are old and outdated, and that the group is using the threat of EEE as a “scare tactic” to support its practices.
Saxe has a biology degree and previously worked as a wildlife technician. He currently teaches in the Diversified Occupations program at the Patricia A. Hannaford Career Center. He said he knows Fern Lake very well.
“It’s my life,” he said. “I swim in the lake almost every day in the summer. I notice when something is wrong, and something went wrong when those fish died.”
Meffe said that the BLSG has not made any sudden changes to its work in and around Fern Lake that would lead to a sudden fish kill.
“Nothing has changed,” he said. “These are the same practices we’ve been doing for years. And we’d love to get water samples from the state. We want to know if there is something we can do to improve our practices.”
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