Fishermen on the River Towy in west Wales are being urged to join the battle against an invasive plant growing along riverbanks.
Experts say the Himalayan Balsam plant swamps native species.
It also impedes water flow and leaves river banks bare in winter leaving them prone to flood damage.
The flowers of the Impatiens glandulifera – first recorded in the UK in 1855 – is rich in nectar and so popular with bees.
Emyr Jenkins, from the Carmarthen Fishermen’s Federation said: “Balsam can be a problem for fishermen because it can impede access to the riverbank.