Fishy Business

July 16th, 2015

How did this get in here? While our volunteers were kindly performing their pond clearance duties on Wednesday, a flash of gold popped out of the duck weed. A fish.

How did you get here, little carp?

How did you get here, little carp?

It was a small, golden creature that looks – to our semi-educated eyes – like a carp. We then saw another, then another, and another, all pretty small but surprisingly numerous.

Oddly, when clearing the pond just a fortnight ago, there were no fish sightings. None at all. The only realistic conclusion is that a citizen has unilaterally taken a course of fish diversification in the public parks of BN2. Or, to put it another way, someone emptied their fish tank into our pond.

The thing is, these fish are not really welcome in the Queen’s Park pond.

“We don’t want them in there,” explains Park Ranger Lindsay Cattanach, “because they breed prolifically, disturb the base of the pond, deoxygenate the water and eat the pond wildlife including tadpoles, newtpoles, water beetle larvae and various other important micro organisms.”

Close up carp

Close up carp

“Carp are the worst of all native fish to have in Queens Park pond as they feed by grubbing in the fragile silt at the bottom of the pond causing de-oxygenating clouds of mud as well as preventing oxygenating plants from taking root. ”

The carp (Cyprinus carpio) is included in the list of the World’s 100 Worst Invasive Species, along with the grey squirrel, the Asian tiger mosquito and Japanese Knotweed. And carp breed like crazy, with a female typically laying 300,000 eggs at a time.

Pond Volunteer leader Chris Lowe adds: “We caught 40 carp between 2cm and 4 cm long but there are likely to be many hundreds more. The pond was emptied in 2005 because the water quality had deteriorated so badly that poisoness blue-green algae was forming. A number of lice infested carp were removed.

“It took over a year for the pond to fill naturally with rainwater, but now, 10 years later, there is a healthy crop of Hornwort (one of the best oxygenating plants) and huge diversity of water creatures including newts and at least four species of Dragonfly.”

Chris Lowe [right] and friends examine the catch of the day

Chris Lowe [right] and friends examine the catch of the day

So, in the future, please do not think of liberating your little fishes in the waters of Queen’s Park.

The next pond clearance is Wednesday 29 July,  1pm, and we’ll update you then on this fishy business. Or you can slip on a pair of waders and take a look for yourself.

Thanks to volunteers Andrew Browne and Maddy Brunner for coming to help on Wednesday. See full volunteering schedule here.

Lindsay Cattenach (centre), with volunteers Maddy and Andrew

Lindsay Cattanach (centre), with volunteers Maddy and Andrew