Boaties and anglers in the Bay of Plenty are reminded to clean their boats before taking them into new lakes or rivers in the region for the opening of the trout fishing season.

The Bay of Plenty Regional Council wants to remind boat users of the absolute importance of checking boats and trailers for weed fragments.

Bay of Plenty Regional Council Land Resources Manager Greg Corbett said it's all too easy to transfer strands of aquatic weeds from one lake to another.

"We have these damaging weeds in some of our lakes but don't want them spread any further - and boaties and anglers have a major part to play in that."

Mr Corbett said it's important for boaties to inspect their boat including its propeller and anchor chain, as well as the trailer and for anglers to check their gear including waders.

"People need to pick off any weeds and if necessary wash down their boat and gear to ensure the weeds aren't transported to other lakes."

The reminder comes with strong support from NIWA and Regional Council staff who discovered hornwort during surveillance work in the south west bays of Lake Okataina in April this year.

Mr Corbett said it is probable that the hornwort was introduced to the lake via a boats anchor warp due to the boat owner neglecting to check for weed fragments prior to entering the lake.

"Lake Ōkataina is an exceptional lake with very good water quality, and high biodiversity and recreational values worth protecting.

We're working with Land Information New Zealand and Te Arawa Lakes Trust to try and eradicate the hornwort infestation which can be a costly and time consuming exercise," said Mr Corbett.

The lake had been free of two of the most damaging aquatic pest plants, hornwort and egeria.

Known infestation areas in Lake Okataina have been contained and are restricted from access. A weed cordon will soon be set up at the boat ramp to minimise further incursions.

Bay of Plenty Regional Council staff will be monitoring the boat ramp at Lake Okataina for the start of the trout fishing season as part of their public awareness campaign on aquatic pests.