Show search form

Invasive Non-Native Species

British Canoeing is committed to protecting the environment, particularly when it comes to tackling Invasive Non-Native Species (INNS).

Plants and animals that did not originate in the UK can cause serious environmental problems and cost our economy about £1.7bn each year.

Expand What are INNS and their impacts?

What are INNS and their impacts?

We have been working with our partners and brilliant volunteers to control, monitor and remove, where possible, harmful species which have been introduced to our waterways.

About 2,000 plants and animals have been introduced, often accidentally, to the UK from all over the world.

Five simple things you can do to help >>

Many are harmless, but some species have had a detrimental impact on our native species as well as our own health and the activities we enjoy.


The wrong plant in the wrong place can be damaging to the environment, impacting on the wildlife that depend on our outcompeted native species.

The non-native species secretariat (NNSS) has a very useful Be Plant Wise guide on its website.

Below are some of the species that affect paddlers, specifically.

Floating pennywort, introduced as an ornamental pond plant, can grow exponentially and clog up waterways, making it hard to paddle.

It can deplete oxygen levels, killing fish and invertebrates as well as outcompeting native plants. 

Click here for a floating pennywort ID sheet

Other damaging species include Himalayan Balsam, which can out compete native species, particularly on riverbanks. 

Giant Hogweed, which can grow up to 5m, has a toxic sap which can cause a blistering of the skin upon exposure to sunlight. (ID sheet)

Australian Swamp-stonecrop can form dense impenetrable mats and grow 200 times faster than native pond plants. (ID sheet)

Water primrose is an alert species, which means if found you must report it to iRecord, here. They are at just a few sites, but can produce hundreds of seeds per year. (ID sheet)

Water fern, a small free floating plant, can cause the water’s surface to appear solid. (ID sheet)

Parrots feather, which has blue-green feather-like leaves, can block ditches and dominate ponds. (ID sheet)

What about animals?

Paddlers need to be aware of one particular pair…

When killer shrimps enter a new waterway they quickly kill native invertebrates and small fish. They breed fast and are difficult to control.

Killer shrimp can survive for up to 16 days in damp paddling equipment and clothing.

Signal crayfish, which pose a huge threat to our native white-clawed crayfish, eat aquatic plants, invertebrates and fish.

They also burrow into river banks causing erosion to those areas.

Paddlers should report sightings of signal crayfish. Also, please check your craft and equipment during a clean.

Expand How can paddlers help?

How can paddlers help?

As a paddler you may come in contact with these harmful species when moving between different watercourses with your craft.

Because of this you have a vital part to play in stopping the spread of damaging plant species.

The Non-Native Species Secretariat (NNSS) have produced a handy guide for paddlers to help stop the spread.


Check your boats, equipment and clothing for living organisms. Remove anything you find and leave it at the site.


Clean everything thoroughly as soon as you can, paying attention to the inside of your boat and areas that are damp and hard to access. Use hot water if possible.


Drain water from every part of your boat and dry with a sponge or towel before leaving the site. Dry everything thoroughly for as long as possible. Some invasive plants and animals can survive for two weeks in damp conditions.

Invasive Non-Native Species news