You probably wouldn’t think a small shellfish would be much to worry about in the great scheme of things – but then you might not ever have heard of the quagga mussel and the impact it can have when it gets into a waterway.

Let's bid a warm welcome to British Summer Time and hope that the signal for the clocks to go forward is also a signal for the warmer weather we enjoyed over the weekend to continue.

I've had lots of input from readers on the subject of dredging since I mentioned it a couple of weeks or so ago in the context of flood prevention following the recent inundations.

Chris Smith and the PM must get their act together on flooding

Invaders from foreign lands have generally not proved to be much of a problem for us British since the arrival of William the Conqueror more than 1,000 years ago.

It was three years ago when I first wrote about the invasion of the Thames by Chinese mitten crabs – so called because of the dense hair on the back of their large claws – and I wondered whether readers of this column had spotted more examples in our stretch of the river.

The River Thames is probably cleaner today than it has been for decades. Yet there is still much to do.

I hope you all add a splendid Christmas and New Year break and here we are now in 2013 with (hopefully) a delightful spring and summer of boating and enjoying the river to look forward to.

Way back in June of this year, I first wrote about plans to install electricity generators at Sunbury Weir and I have to admit that I was rather hoping that the proposal had sunk without trace. Obviously not so.

It seems incredible to me but this is the 200th Riverwatch column I’ve penned since first starting it just under five years ago.