A killer shrimp is on the loose. Larger than any native shrimp, it has come to Britain all the way from somewhere between the Black Sea and the Caspian sea. In its native area, it is eaten by larger fish. In Britain, it has no predator!
Having free reign, it kills any pond life - local shrimp, even young fish, damselflies and other insects. It kills much more than it can eat and it has a voracious appetite. The authorities are worried. This creature is not good news.
Sometimes "non-native" species are introduced with very good intentions such as for biological pest control. This is where one species is introduced to control another species naturally instead of using chemical sprays. The cane toad was introduced in Australia to control the cane beetle. But, all did not go as planned. The cane toad ate not only cane beetles but all other types of insects as well.
Moreover, the cane toad squirts a poison when detecting a threat and freshwater crocodiles, snakes and other mammals have died after eating cane toads! The toad multiplied quickly and threw the ecosystem out of balance.
How do these aliens travel?
Like in the case of the cane toad, humans often introduce invasive animals out of ignorance. At other times, invasive animals are smart stowaways! They travel in our ships, with our cargos and ballast water (water used by ships to stay buoyant). They travel in sacks of grain and in pet boxes. In short, we transport them around. Take the killer shrimp -- it likely came by boats and ships to Western Europe and then again by ship to Britain!
So What Next?
The impact of invasive species is second only to habitat destruction. There is much at stake for local economies and even the folks across the Atlantic, in the Great Lakes, USA are worried! Given shipping routes, their waters could be the next target for the shrimp. The British authorities are asking all anglers and fishermen to thoroughly examine their boats and make sure all equipment is dry before putting it in to any other water. Given the global nature of trade and transport today, that is easier said than done!
Video of another invasive shrimp, the noisy pistol shrimp -