Professor Ken Whelan:

There are two answers, really. I will start with the freshwater, divide the two and then bring the two together if that is okay. I have some science that is hot off the press. I got agreement from my colleagues to be able to quote this. It is in reports to the various fisheries boards in Scotland but is not published as science yet. It is in preparation. As part of this likely suspects framework we are trying to divide this into the boxes the Deputy has asked about to try to get a handle on exactly what Dr. Gallagher was saying about the priorities, what is happening here and what can we assign to the various problems and issues.

On the fresh water, we started with a great opportunity because we got some funding through the Atlantic Salmon Trust to look at seven rivers in the Moray Firth in Scotland. It was ideal because some of these rivers are absolutely free-flowing and some of them are very severely impounded. I will show the contrast between a river called the Oykel and one members will know, or at least they will know Lough Ness. This is the whole Lough Ness catchment. What we found with the Oykel, which is perfect at the moment, is it is still seeing problems, a lot of which we think are down to the marine survival. It is perfect in the sense it does not have pollution problems, has next to no problems from forestry, has a very nice gradient and no dams, so it is an ideal candidate as our control. We looked at that and found that not alone were we able to track the mortality of the fish as they moved downstream - we were very surprised that quite a number of these baby smolts die on their way to sea quite naturally without any barriers or manmade impacts – but when we looked and divided up sections of the River Oykel over three years, we saw repeatability. We saw fish disappearing naturally in particular sections and they disappeared in the same section the next year. To us that was really interesting because we were beginning to get at what happens naturally.

Then we contrasted that with the Ness. The Ness has the Caledonian Canal, which I think went in back in the 1840s. With any of our tagged smolts that went into any of the canals, which are interconnected all the time so the water flows in and flows out of the river, we got no salmon surviving in the canal at all, so that is the ultimate in terms of impacts. We also saw quite a low level of survival overall in the Ness and it repeated itself. Whether there was a year with a lot of rain or a lot of drought, we still got this very low survival out of the Ness which did not vary an awful lot. There were a couple of factors working there. There are obviously the manmade obstructions, but discharge pattern is really important in terms of the pattern of rainfall and the amount of rain that comes. As we are seeing this now in a very different sort of envelope than we saw in the past, we have to be careful to not just take the ancient data and apply it to modern numbers; we have to look at these factors as well. At least now we are beginning to understand that any of these barriers have quite a significant impact on the overall survival of these fish. When we looked at the River Deveron, which is another of our seven in Scotland, it was interesting because it is a lowland salmon river and in that case it has a lot of the manmade impacts. It has pollution, barriers and you name it. To a small extent, it has that throughout the catchment. As far as we can see, the mortality seems to be random. All sorts of different things are hitting those smolts as they come down as the different things impact. That is why I mentioned looking at it in a holistic way earlier. We are beginning to get the science now. We are understanding actual percentages with regard to what the mitigation might mean if we removed it or partially removed it.

The Deputy had a question on the marine side of things and that is obviously hugely complicated. Again, through the likely suspects framework, we have been applying ourselves to that and a gem of information we have seen is we asked some colleagues in one of the universities in Scotland to look in detail at plankton. Of course, when the baby salmon go out they are feeding on quite small organisms and very often it is organisms within the plankton that they are feeding on. The changes we are seeing with respect to the overall energy available from the plankton to the salmon since the 1960s are very dramatic. Mr. Horton was mentioning earlier the big drop in numbers, but to some extent we are seeing a situation where, as the committee has heard on numerous occasions, our oceans are changing and changing fast. As a result of that, the overall synchronisation of the fish going to sea, the food available to them, the heat of the water and the disturbance from storms is changing and impacting. We are in a situation where we have two series of factors interacting, namely, the fresh water and the marine.

What we are trying to do, if we can put it in the context of the health service, is that if we have a very seriously ill patient in front of us, the patient is triaged. That was our "likely suspects" framework. Then one sets one's course for stabilisation. Collectively, around the table here, we are trying to stabilise the freshwater output which we have complete control over to see whether we can counterbalance what is happening in larger marine climate change impacts.