ANCASTER NEWS (Stoney Creek, Ontario) 25 September 09 Goldfish kill set to go after clearing hurdle (Richard Leitner)

The Hamilton Conservation Authority has cleared the final hurdle on plans to use a natural pesticide to kill goldfish that are overwhelming two Dundas Valley ponds where nationally threatened Jefferson salamanders breed.

Ecologist Shari Faulkenham said the eradication can now proceed following the approval last week of the plant-based pesticide rotenone for use in Ontario by a provincial advisory committee.

The fish kill had already been endorsed by authority directors, Ministry of Natural Resources and Hamilton Naturalists’ Club. Work is expected to be completed by early next month.

The goldfish were apparently dumped in the ponds by people who wanted to breed them for sale for backyard ponds and, in the case of the Mc Cormack Pond in the Governor’s Road Conservation Area, now number an estimated 40,000 –up from about 50 when first noticed in 2005.

A similar problem looms at the pond by the former Merrick Field Centre in Ancaster –described as the salamanders’ hottest breeding area in the valley – where fish were introduced last year and a new stock was discovered in July.

Ms. Faulkenham recommended the eradication because the goldfish devour anything they can fit in their mouths, including the eggs of the salamanders, which are in the ponds from late March until maturity in late August.

The valley ponds are among only 34 breeding sites for Jefferson salamanders, which are protected by provincial and federal laws.

Ms. Faulkenham said rotenone is relatively harmless to other species but effective on fish because it is absorbed into the bloodstream through their gills and initiates a cellular process that makes oxygen toxic. The eradication isn’t expected to affect the ponds’ salamanders or newts, but may kill some tadpoles of green frogs, which take two years to mature and will be the lone other gilled species present at that time.

But Ms. Faulkenham said the frogs aren’t rare and are expected to quickly recover.

She said the ponds will be dammed with sandbags to prevent any surface-water outflow and the authority will be closing trails in the vicinity. The public is also asked to avoid visiting the ponds during the eradication.
Goldfish kill set to go after clearing hurdle

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