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Fighting Pennywort and Banning Magnet Fishing


Signs on the Top Stream

There are two new signs on display on
OBAS waters: A notice of spraying of aquatic herbicides to eliminate Floating Pennywort, and No Magnet Fishing Allowed.

The Scourge of Floating Pennywort

Originally from the Americas, Hydrocotyle ranunculoides, the Floating Pennywort is an invasive plant that forms dense interwoven mats of vegetation that can quickly cover the water surface (it grows up to 20 cm a day). By covering the water surface it affects the water's oxygen content and is capable of suffocating indigenous plants and fish. It has become a major problem on the River Great Ouse, including OBAS waters and, in association with the Environment Agency, we plan to eliminate it from OBAS waters. In the words of the Environment Agency:

"A key challenge is that no one organisation or landowner bears responsibility for tackling non-native invasive species. There is no legal obligation for riverside landowners to remove Floating Pennywort (unless they are responsible for introducing it). Similarly, the Environment Agency has no duty to remove it.

"But it's a bit like dealing with litter; we can all play a part in disposing of it properly and tidying up, even where it's not our fault."

OBAS's contribution to the Environment Agency / OBAS collaboration includes five society members who have taken and passed the City & Guilds Level 2 Award in the Safe Application of Pesticides using Pedestrian Hand Held Equipment. They operate in accordance with the Environment Agency's process of chemical quantities and application.

Whilst hand picking the weed will be our main approach to the floating pennywort's removal, there will inevitably be patches of the weed that will require a chemical spray to kill it. These chemicals are diluted to a weak solution as defined by the Environment Agency, and sprayed directly on the pennywort. We have erected signs to inform the general public, dog walkers, ramblers, etc., to advise them of spraying taking place, and to provide contact details for any who are concerned.

Floating Pennywort removal is scheduled to take place on New Cut, the Top Stream, the Mill Stream and the Car Park Pool.

Magnet Fishing

Magnet fishing, also known as magnetic fishing, is a form of underwater treasure hunting that has increased in popularity over the past few years, and is a nuisance to anglers and others who visit the river bank.

Unfortunately, incidences of magnet fishing have increased recently on OBAS controlled waters - its practitioners seem oblivious to our Societies anglers, acting without due consideration, and also discard caught metal objects on the river bank. Consequently, your committee has formulated a new rule, rule 27, to be added to OBAS rules, banning this activity. Signs have been erected to this effect in prominent positions along the river bank.