In a previous post, I mentioned the improvement in the water quality on the old estate lake. Whilst I am sure that this was, in part, the result of the estate’s efforts to persuade its neighbour to amend its farming practices, it coincided with the arrival in the lake of the invasive zebra mussel.

It is generally held that invasive species are A Bad Thing. However, I am far from certain that the zebra mussel is an unmitigated disaster. I claim no sound scientific knowledge on this particular subject so would welcome some genuinely informed comments. I understand that they alter the eco system to the detriment of some insect life and of our native swan mussel. However, they seem to benefit other insect life and certainly improve the water clarity which can improve weed growth and oxygen levels. As I understand it, they can impact badly on the bottom-feeding fish but can work to the advantage of fish which feed higher in the water. This could result in a decline in the numbers of cyprinid species in the old estate lake alongside an increase in the perch population. I wouldn’t like to predict how this would affect the pike.

I know that zebra mussels have established themselves in the Erne system in Ireland but don’t know how this has impacted on the trout fishing. I am always somewhat wary of accepting so called 'scientific evidence' as often the so called scientists have an axe to grind and will manipulate data to support their particular prejudices.

Please don’t misunderstand what I am saying in this post. My lack of firm conviction doesn’t imply indifference. Certainly, I wouldn’t want to be responsible for spreading zebra mussels to new waters. I always ensure that my equipment is cleaned down and dried in accordance with recommended procedures. Whilst I haven’t fished many waters containing zebra mussels, I have more experience of the signal crayfish which has definitely had detrimental effects on the waters it has colonised.

Ignorance will aid the zebra mussels’ cause. When I fished on Lough Corrib last autumn I would have been unaware that zebra mussels had invaded the lough, had it not been for my host, Michael Canney, telling me about the situation. Had I remained ignorant, I could easily have been responsible for spreading them to another lake. I hate the idea of a proliferation of intrusive warning signs around every lake and along every riverbank. That said, anglers do need to be made aware of the risks and do need to take appropriate measures.

I don’t know if any readers have practical experience of how to control or eradicate zebra mussels once they have established themselves in a water. The television programme that I viewed on the subject last year, didn’t offer any sure-fire solutions.

I look forward to being educated.