The Killer Shrimp And Other Alien Pests

There is a war being fought that most of us know nothing about. Invasive species like the American Bullfrog and Egyptian Geese have been wreaking havoc on the UK ecosystem for years. The effect these species can have on an economy is drastic. Back in 2008, Joan Ruddock, the minister for biodiversity, estimated £2bn a year is spent containing and cleaning up the mess left by our unwanted visitors.

As government and non-government bodies fight to keep our ecosystems and way of life intact, as a whole we need to be aware of current threats and what we can do to help.

As published by the GB Non-Native Species Secretariat (NNSS), the rapid response protocol has issued species alerts for a number of aliens. Any sightings of these species should be directly reported to the NNSS at this address: along with a photograph and location details.

Killer shrimpThe Killer Shrimp

Known as the “killer shrimp”, this 30mm long shrimp has caused a widespread reduction in biodiversity throughout Western Europe and even the extinction of some local species.  Native to the Ponto-Caspian region, which stretches between the Black and Caspian Seas, the killer shrimp likes to – as the name suggests – kill other animals by shredding them to pieces with its relatively large manibles, but not only for food: it can and will kill or maim things it has no interest in eating. It prefers cool, fresh or brackish water but can adapt to levels of up to 20% salinity and can live in temperatures as high as 35 degrees C.

No one really knows how the killer shrimp came to the UK, but they could have travelled in the ballast water of ships or been carried by migrating birds. One thing we do know, however, is that it was first spotted in the UK on 3 September 2010, in Grafham Water, Cambridgeshire, even though scientists had been warning (of its imminent arrival on our shores for almost 10 years.

Creeping Water-Primrose

Water primroseTwo subspecies of a plant from South America, both types of Creeping Water-Primrose, can cause significant problems with bodies of water. Creeping Water-Primrose grows along lakes, ponds and streams, forming dense floating mats in open water. This seemlingly harmless flower clogs irrigation systems and disrupts water navigation, which increases the risk of flooding in certain areas. It also provides breeding areas for mosquitoes, which lower the quality of water sources and habitat for wildlife, and it can choke out the light that other species need to survive underwater.

Like many other invasive species, we’re not sure how the plant came to the UK (weird how people don’t admit they introduced massively destructive species to an area). It is likely, however, that someone brought it to the country to use it as an ornamental plant, without realising the possible extent of their actions. After all, it is a lovely plant. Nonetheless, the NNSS has banned the plant from sale and are looking at other measures to eradicate it, including spraying glyphosate on the mats of the plant.

Here is a video illustrating the threat Creeping Water-Primrose poses to Breamore Marsh and how they are trying to get rid of it.

Carpet sea squirtCarpet Sea Squirt

The carpet sea squirt may have a cute name, but it is a real threat to the fishing industry. It is thought to come from Japan, though it is found all around the world. It was spotted in Scotland in 2009, but it has been in Wales since 2008. In fact, most experts believe that the squirts hitched a ride on the hulls of leisure craft that had travelled to Largs in Scotland from Wales or Ireland, then quickly reproduced in the new region.

Not only is it a major pest, but the squirt is also very hard to kill. Scraping it off the bottom of the sea or ships will just produce fragments that can reproduce wherever they land, introducing it to new areas of the sea. If it spreads to open water and starts to cover sea beds, it can kill mussels and other mollusks and destroy the spawning grounds of various sea life.

Currently in the UK, the carpet sea squirt has been contained in marinas, where it can be eradicated by starving it of oxygen and water when it dies. Because the squirt tends to stick fast to surfaces like the hulls of ships, it reproduces very quickly and it doesn’t need much of anything to survive. If left untreated the squishy little nuisance could suffocate the fishing industry in infected areas. The NNSS predicts that over a ten-year period we could see up to a loss of anywhere between £1.3 and £6.8 million in the mussel industry alone. From one squishy little creature.

Any sightings of the carpet sea squirt should be directly reported to the following agencies:

  • In England, Natural England: 0845 600 3078
  • In Wales, Countryside Council for Wales: 0845 1306 begin_of_the_skype_highlighting              0845 1306      end_of_the_skype_highlighting 229
  • In Scotland, Scottish Natural Heritage: 01463 725000

And if you’d like to know more about the carpet sea squirt and how it is being fought, check out this.


Glis glisGlis Glis

Also known as edible dormice (the ancient Romans loved snacking on them), Glis glis were introduced to Britain when the Second Baron Rothschild in 1902 brought six of the animals from mainland Europe. They are not just nuisances, although they do make very loud noises late at night. They can cause some severe damage to houses, as they chew through cables and insulation looking for food. One property owner even found one eating through a woolly jumper!

Though the Glis glis can give birth only once a year, they can have up to 11 young at a time. Their numbers have really added up over the course of century they have been here, largely to the relatively safe existence the Glis glis enjoy. Under Section 11(2) of the Wildlife and Countryside Act 1981 (as amended), killing or trapping the edible dormice is prohibited, unless you have a licence. (Fortunately, Rentokil do have the licence – and an exclusive contract – to trap the Glis glis.)

These and other invasive species (check out the list here) are a constant threat to human life and the ecosystems to which they are foreign. Government agencies can’t monitor the spread of these pests alone, so we all need to keep our eyes peeled and report when we think we have spotted on of them. That way we’ll stand a better chance at maintaining a healthy and balanced ecosystem for future generations.

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