Tuesday, March 15, 2011

Outstaying Their Welcome?

The next in our student blogs comes from Paul Rhodes on the invasive killer shrimp......

“Aliens” as they’re popularly titled or rather non-native invasive species have again struck the news headlines.  Dikerogammarus Villosus the perhaps aptly named ‘Killer’ Shrimp that was first reported in the UK last Autumn in Cambridgeshire has once again been identified, only this time in the welsh waters of Cardiff Bay and Eglwys Nunydd reservoir in Port Talbot. The ‘killer’ shrimp, of a Ponto-Caspian, Eastern European origin is feared by ecologists for its larger size (up to 3cm) in comparison to native species, its spread rate and destructive feeding nature that includes an almost ‘sloppy’ eating style, often killing many more invertebrates and small fish than it requires.  Non-native invasive species, well known as a threat to local biodiversity have in a recent report been tagged as arresting significant pressure on ‘taxpayers’ money and thus threatening to our economic prosperity.  What should be done to protect our native species and at what cost should this come?

Invasive species can become established in foreign habitats on a premise of ecological dominance over their native counterparts, threatening biodiversity, conservation efforts and indeed the ecosystem services that we ourselves often rely so heavily upon.  “The Economic Cost of Invasive Non-Native Species to Great Britain”, a report published in 2010, funded by the Scottish Government, DEFRA and the Welsh Assembly has estimated the cost of both marine and terrestrial invasive biota to be a chilling £1.7 billion to the UK economy.
Invasive non-native species such as the Japanese skeleton shrimp (Caprella mutica) and potentially the colonial sea squirt (Didemnum vexillium) have been identified as costly creatures, both causing an increase in the time and labour spent anti-fouling equipment and stock in order to protect a premium market value in both the fin- and shellfish sectors.  Similarly, as a strong drive by the Scottish government to produce 80% of our energy from renewable technologies by 2020 prevails there will no doubt be additional engineering concern with the spread of such bio-fouling non-native species, inhibiting potentially the functionality of many of the offshore renewable energy devices in both development and operation.
 I am firm in my belief that there will continue to be reports of non-native species intermittently appearing in the media as international activity continues and as our climate continues to undergo rapid change.  Unfortunately, however I equally expect that as our local marine environments continue to be altered by the establishment of stronger, more resilient non-native species, that not enough could ever be done to restrain the invasion of the unwanted pests that, foreseeably, would come as a direct cost to the valuable marine assets that society directly or indirectly enjoys.
by Paul Rhodes.


  1. Great article! I was just thinking, what is the price estimated to be for the protection of fish from native species such as lice that cause havoc to farmed salmon? From what I understand there is a great amount of effort, time and money put into the aquaculture to produce products that will deter such parasites. Although invasive species seem to be an increasing problem, some of our native species seem to have been causing problems for much longer, but because they're native is it seen to be less of an issue?

  2. Arguably not, using the aquaculture of Atlantic salmon as an example indeed the fouling of equipment, particularly the nets is a problem due to the establishment of native algal species on such artificial structures. Whilst there are methods and techniques that have been developed for the removal of these fouling species it was indeed a problem to be overcome and a cost to be absorbed in the infancy of the Atlantic salmon aquaculture industry.

    My argument was that the establishment of certain tougher non-native species, again for example the colonial sea squirt could require a different approach in the antifouling of equipment to maintain adequate stock protection. Whilst you’re correct in highlighting the significant cost to aquaculture in the control of parasitic sea lice I would argue that at a time when profit margins are continuously been pinched and budgets squeezed that any additional cost could pose detrimental to a number of maritime industries and hence the implications to be faced with imminent future invasion of tougher non-native species is most certainly an issue to bold to ignore.