Killer shrimp? Meet the aliens invading our waterways
What do Killer Shrimp, Floating Pennywort, Quagga Mussels and Himalayan Balsam all have in common? The answer: they’re part of range of plants and animals from overseas invading our waterways, ponds, rivers, canals and lakes.
These plants and animals make their way over to our waters from all around the world either intentionally by being imported, or accidentally by hitching a lift for example in recreational equipment or the bottoms of boats. And they can cause huge damage to ecosystems - even wiping local species out.
We caught up with Chris Gerrard, Head of Biodiversity for Anglian Water to find out more about these invasive species:
“Invasive, non-native species can come in all shapes and sizes; from Floating Pennywort, a green leafy plant, to Killer Shrimps, which despite their small size can devastate native populations of insects, to Zebra Mussels which can multiply fast and clog up the intake pipes which come from our reservoirs.
We first discovered Killer Shrimp in our Grafham Water reservoir in 2010, and more recently in another of our reservoirs, Pitsford Water, in 2015. Since then we’ve worked with the Environment Agency, DEFRA and our angling community, amongst others, to put in place clear guidelines for anyone using our reservoirs. We use the Check, Clean, Dry procedure.
Killer Shrimp, photo credit Environment Agency
Check: Anglers should check all clothes and equipment for any visible mud, plants or animal matter and, if found, leave these at the water body, in particular the seams and seals of boots and waders where plants and animals can be hiding!
Clean: Equipment should be hosed down and cleaned on site.
Dry: All clothes and equipment should be thoroughly dry for 48 hours before it is used elsewhere. Some non-native species can survive for up to 15 days in damp conditions and up to 2 days in dry conditions, so the drying process can really help stop the spread.
Invasive non-native species are a growing problem for the water industry so it’s in our interest to make sure we’re promoting Check, Clean, Dry and preventing their further spread. Not least they can be a very costly problem. It’s estimated the water industry spends £7.5 million each year managing these species.
Anglian Water staff play an important role in managing this biosecurity. We train our staff on the check, clean, dry method and our operational staff have guidebooks to help them identify and report sightings of the species, so we can deal with problems quickly.”
What are the top 5 invasive species?
1. Zebra and quagga and mussels
Originally from the Ponto-Caspian Region of Eastern Europe, populations of these mussels can multiply fast and clog up the intake pipes that come from our reservoirs. They also help to encourage the growth of blue-green algae, harmful to humans and many wildlife species. Anglian Water spends thousands of pounds every year dealing with zebra mussels.
2. Killer shrimp
The natural home of the killer shrimp is the tributaries of the Black Sea and Caspian Seas. But now they can be found in large numbers at Grafham Water reservoir and Pitsford Water reservoir. As the name suggests they are an aggressive species, killing native wildlife, including some fish. They are voracious breeders and impossible to eradicate – however we can help to slow their spread.
3. Himalayan Balsam
This plant, originally from the Himalayas, was introduced as a cultivated plant in gardens in England in the 19th Century but later began to take over riverbanks, easily outcompeting native plants. When it dies back in winter it leaves river banks vulnerable to erosion. This causes sedimentation which is expensive for us to clean up from the water.
One way to help the fight against Himalayan balsam is to download the Plant Tracker app, developed by the Environment Agency and Bristol University, to help submit sightings.
Anglian Water is also helping through the RiverCare project which helps local volunteers to keep their local stretch of river litter-free and free of invasive plants.
Himalayan balsam, Crown Copyright 2009, photo credit GBNNSS
4. Japanese knotweed
This fast spreading plant was first recorded in the UK in Glamorgan in 1886 and is now a major headache for gardeners. It is often found on river banks and can even grow through concrete and gaps in floors and patios, causing expensive damage. It needs to be removed carefully and legally, so if you find it on your property, take specialist advice before doing anything. We’re on the look out for it on our sites – the sooner we get rid of it the less damage it will do.
5. Floating Pennywort
Originally from North America, this floating plant can grow up to 20cm a day and rapidly spreads across ponds, slow flowing stream and rivers. It out-competes native species by blocking out light and causing de-oxygenation. The dense mats it forms chokes drainage systems, block waterways, block filters and intakes, prevent angling access, and increases the risk of flooding.
For more information visit the Anglian Water website and search ‘biodiversity’.