From the May 10, 2000 Edition
From the May 10, 2000 Edition
Lampricide treatment project turns
the Bighead River green
Treatment should exterminate 75,000 lamprey
By Scott Woodhouse Express Staff
Wayne Westman wades upstream against the current of
the Bighead River near Bognor.
His hip waders splash against the unnatural green colour of the normally
clear headwaters as he stops and uses his dip net to fish something from
the riverbed.
Success. He's just found the first dead sea lamprey - a few steps further
and he finds another.
Things are going well. If only the rain will hold off.
Residents along the Bighead River may have noticed a green tinge to the
water on Sunday and Monday after the river was treated with a chemical
to kill sea lampreys. This is the first time the river has been treated
under the joint Great Lakes Fishery Commission project, which was created
by a convention between Canada and the United States in 1956 to combat
the infestation of the sea lamprey and improve fishery resources.
"This is the first time we've seen the lamprey in the Bighead River,"
said Westman, a treatment supervisor with the Sea Lamprey Control Centre
based in Sault Ste. Marie.
The Bighead has been checked periodically, but up until last year, there
were no sea lamprey larvae in the river. Further testing revealed a large
enough infestation to warrant the lampricide treatment, he said.
Before a river is treated, explained Westman, an assessment crew tests
for the presence of sea lamprey larvae by taking a section of the riverbed
and sticking electric shock probes into the sediment where the larvae live
for the first 4-5 years of their life.
Westman said that assessment revealed the treatment would kill between
4,000 and 5,000 adult lamprey that would leave the river this summer to
attack and kill fish in the Georgian Bay. But more importantly, the chemical
would kill another 50,000 to 70,000 larvae in the river before they reached
adulthood.
The crew arrived on Friday and residents may have noticed a red dye in
the river. The treatment crew first tests the flow of the river to determine
exactly how much of the pesticide TFN will be needed.
"First we time the flow of the river as well as measure the the volume
and density of the water," said Westman during an interview Friday.
"We'll put together the information on Friday and Saturday and then
if it doesn't rain, we'll start the treatment on Sunday."
Once the treatment process is started, the crew of 17 will work for 24
hours straight to make sure the chemical levels remain constant for the
required period of time necessary to kill the larvae.
"We want to expose the lamprey to six parts per million of TFN for
nine hours in order to get 100 per cent mortality," he said. In order
to do that, the crew will attempt to maintain six to eight parts per million
all the way down the river. Keeping in contact with two-way radios, the
crew members constantly test the river at key locations throughout the
process.
The pesticide TFN (3-trifluoromethyl-4-nitrophenol for you chemistry grads
out there) was created specifically for the control of sea lamprey and
has little or no effect on other wildlife in the river. It has been used
for more than 30 years and was extensively tested before it was approved
by the Environmental Protection Agency in the USA and Environment Canada.In
order to achieve this, the crew operates three application sites at the
various headwaters and five booster sites downstream to make up for additional
flow created by tributaries like the Rocklyn Creek.
As Westman and technician Randy Stewart operated the application site in
Bognor, two local residents walked by with their dogs and asked what was
going on. They had many questions, especially about the effects the application
would have on shore wells along the river and what would happen if animals
drank the water from the river while it was being treated..
Westman is used to such queries,and seemed to have all the right answers.
In fact a booklet published by Great Lakes Fisheries Commission Commission
outlines answers many of the concerns that have been expressed by people
about the process over the years.
Tests have shown that even after ingesting high concetrations (5,000 ppm)
over a period of 90 days, laboratory rats showed no adverse effects from
TFN. The test dosage was equal to a 150 pound person drinking 179,000 eight
ounce glasses of TFM treated water each day.
Westman said all of the landowners along the river had been notified of
the project and added the chemical would not permeate into any shore wells.
He did say, however, that if people were drawing water right from the river,
they may notice a pale yellow colour and a chemical taste. Filtration through
activated charcoal effectively removes all the compound while unfiltered
water may have a faint odour or slight chemical flavour but is not harmful.
Westman explained that TFN is effective against the lamprey because their
bodies can't break the substance down, whereas in humans and other non-targeted
species, it is simply eliminated from the system.
It's a busy summer on the road for Westman and his crew. They came to Meaford
after treating two rivers near Hamilton in Lake Ontario and after they
finish here they move on to rivers in New York State.
