‘Killer Shrimps’ claim first victim: rational debate

The wildlife news today is the discovery in the UK of the alarmingly named ‘Killer Shrimp’ Dikerogammarus villosus.

And pretty quickly we can see what is becoming a bit of a knee-jerk reaction to non-native species.

Here http://www.bbc.co.uk/news/science-environment-11246642

and

Here http://www.dailymail.co.uk/sciencetech/article-1310496/Killer-shrimp-spotted-UK-waters.html.

are good examples.

Even The Sun has joined in!

Of course, some alien species are seriously bad news. But before we all get too gloomy about this marauding beast which ‘often kills its prey and leaves it uneaten’, it’s worth just looking at some of the not-so-bad-news-about-the-animal.

Here’s a quote from some biologists who studied this species, and other alien freshwater shrimps, in France.

“Non-native species were dominant at all sites in the main channel of the Loire River, but native species were still present at most of the sites. We found that the invaders have failed to colonize most of tributaries of the Loire River. At the regional scale, we found that since the invaders first arrived 25 years ago, the global amphipod diversity has increased by 33% (from 8 to 12 species) due to the arrival of non-native species. We discuss the possibility that the lack of any loss of biodiversity may be directly linked to the presence of refuges at the microhabitat scale in the Loire channel and in the tributaries, which invasive species have been unable to colonize. The restoration of river quality could increase the number of refuges for native species, thus reducing the impact of invaders.”

See: http://www.springerlink.com/content/h146146678480587/

And I think this is worth keeping in mind too from the DIASIE database…

“It [Dikerogammaruslocally eliminates other gammarid species through competition and predation. There have been some
observations of the species eating fish eggs or attacking small fishes.”

Now I’d be the last to minimise worries about alien species – we do have some very troublesome ones – but we do also need to keep a sense of proportion. We spend a lot of money on alien species control – and some of it looks neither necessary or cost-effective.

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