10/16/2012 01:15 EDT | Updated 12/16/2012 05:12 EST

Leg up, or pond scum purged? Latest numbers leave bullfrog battlers jumpy

VICTORIA - These froggies have gone a-courtin', and that has experts worried as they try to get the jump on the spread of American bullfrogs across southern Vancouver Island.

Amphibian expert Stan Orchard says teams scooped about 3,000 of the invasive, and voracious, bullfrogs out of southern Vancouver Island lakes and ponds this year, down almost 50 per cent from the 5,500 eradicated last year.

Orchard heads a project to stop the spread of the dinner plate-sized bullfrogs with the Borg-like mentality, and says a lower kill rate could mean good — or very bad — news.

He says despite almost a decade of effort, the pests, which are not native to Western Canada, seem to be spreading further afield.

But he also says they appear to have been bounced from the marshy lowlands of Swan Lake in Saanich, and they haven't yet invaded the Sooke Lake ecosystem west of Victoria.

Native species such as smaller frogs, birds and fish are all at risk because the bully bullfrogs will overpower and eat anything they can cram into their huge mouths, which are almost as wide as their bodies. (CFAX)