Cornwall Wildlife Trust and the Loe Pool Forum have teamed up with children from St Michael’s School in Helston to keep the River Cober cleaner.

Pupils went into Helston armed with yellow spray-paint and fish-shaped stencils. They carefully sprayed yellow fish symbols next to Helston’s historic kennels and surface water drains, to clearly mark the places where water empties straight into the River Cober. The symbols are to remind people that it should be ‘Only Rain Down the Drain.’

This Environment Agency initiative helps to reduce river pollution. Food and other organic waste emptied into surface water drains will get to the nearest stream, leading to rapid growth of naturally occurring algae and bacteria. This growth can block out sunlight and use up dissolved oxygen which can kill off sensitive wildlife species like dragonfly and mayfly larvae. The larvae and adult forms of these insects are food for brown trout, swallows and several bat species, so anything other than rain in the surface water drains can have a devastating effect right up the food chain.

Ben Osborne, year three teacher at St Michael’s, said: “This kind of thing brings science to life for our school children. The event gave them a chance to see how our behaviour affects wildlife, but also meant they could do something positive to help protect it. It helped them understand that we all need to take responsibility for protecting our local environment, as well as setting a good example for us grown-ups.”

Yellow Fish is part of a bigger effort by multiple organisations to bring benefits for water quality, wildlife and people in and around the River Cober. The river is affected by the land which drains into it, so work is done across the whole Cober drainage basin – from Four Lanes down to Loe Pool.

The Loe Pool Forum coordinates conservation work across the area which involves Cornwall Wildlife Trust, National Trust, Natural England and the Environment Agency. Cornwall Wildlife Trust’s wider work in this area is funded by the Environment Agency and South West Water and supports farmers to manage their land more sensitively for wildlife and water, as well as part-funding infrastructure improvements.

Two new roofs over farmyard manure stores have been constructed recently, which stop nutrient-rich dung washing into the river during heavy rain. Farm nutrients starve river species of light and oxygen in the same way as waste emptied down the drain so the roofing protects wildlife but also keeps a stockpile of muck which the farmer can spread on the fields in dry weather.