Weed cordon installed at Lake Ōkataina

An exciting initiative which began in Lake Rotoma has now been applied to Lake Ōkataina.

Bay of Plenty Regional Council has installed a weed cordon around the boat ramp at the main beach on Lake Ōkataina. The weed cordon has been specifically designed to prevent the spread of aquatic pests that are present in nearby lakes.

Lake Ōkataina is particularly vulnerable to invasion by two of the worst aquatic weeds, Hornwort and Egeria which can spread easily through fragments transported from nearby lakes.

An isolated site of Hornwort which was discovered last year at the southern end of the lake is under active control by the Regional Council in a hope to eradicate the infestation.

Bay of Plenty Regional Council Biosecurity Officer Hamish Lass said the cordon was constructed from used mackerel purse seine net donated by Sanford fisheries.

“Shade cloth covers the top two metres of the cordon and has been designed to contain any fragments from other lakes that may have been on boats or boat trailers.” Mr Lass explained.

“When a boat enters the water, weed fragments will wash off and be caught in the net within the controlled area.”

“A fish pass has also been installed so trout can still migrate along the shoreline of the lake,” Mr Lass said.

The cordon is marked out with buoys and port and starboard makers. Signs also explain the cordon’s purpose and have navigational instructions.

The area within the cordon will be sprayed out annually with diquat herbicide to prevent weed growth and checked regularly for any Hornwort or Egeria incursions.

Lake users have already welcomed the cordon and the efforts by the Regional Council to help maintain the lake’s quality.