A little ‘monster’ in Lough Derg
Dr Dan Minchin of the Lough Derg Science Group has discovered several invasive species in the lake over the years. Here, he reveals his latest find, aptly called ‘The Demon Shrimp’ to coincide with this spooky time of year.
Lough Derg has a reputation for monsters, allegedly seen from the shore by a priest and visiting professor.
Those of a different kind include the world record pike at 90.5 lbs (42 kgs) at five foot eight inches, caught just up-lake from Killaloe in May 1862, or the exceptional trout of 14 lbs (6.5 kgs) landed in more recent times by Ballina angler, Ger McKeogh.
The latest found ‘monster’ comes at a disappointing inch in length and weighing in at a few grams. It was found not far from the old bridge at Ballina-Killaloe, now used for pedestrians.
So, what does it look like? If you have been to the seaside and turned over the seaweed at the top of the shore, you may have noticed hoppers like ‘giant fleas’ leaping about.
Demon shrimps look quite like these but do not have the ability to hop. When out of water they scutter about on their sides. They have a striped ‘Denis the Menace’ sweatshirt look, and what makes it different to our native shrimps are the two prominent cones on its rear-end, like boils, each topped with two small spines.
It is known as the Demon Shrimp having come from the Black Sea region, that includes Transylvania, and this is only part of the story.
It took a long journey of 70 years to get to Ireland having passed along the Danube River and to other rivers with linking canals.
It ‘hopped’ to Britain where it was found in 2012 and now just over a decade later it would seem to have made its home here.
They have been found in Lough Derg among zebra and quagga mussels, that also came from the same Black Sea region, living between their clusters or in amongst dead shells. They are most often seen curled up and lying on their side, and when out of water may skitter about.
HOW DID IT GET HERE?
So, you may ask, ‘how did they get here?’ The truth is that we really don’t know; but some possible guesses include their arrival as fouling on imported boats, carried by ferry, or with angler’s equipment, especially keep nets and the bags called ‘stink’ bags used to hold these nets.
Scientific studies have shown that they readily attach to ropes, so such materials removed from water are likely to pose some risk.
So, why do we worry about the Demon being here?’ While it eats a wide range of aquatic foods, it can feed on fish eggs, insects and even its own kind.
While fish may enjoy eating demons, we do not know if these shrimp will affect the lives of other fish foods.
Well, let’s not spoil Halloween with demons. But should you be moving boats overland, don’t forget to clean-out the boat and the trailer of weed, and we hope that ‘stink’ bags are all well washed out.
After all, we don’t want a stink, do we?