hf
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Posts: 1,807
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Post by hf on Jan 21, 2008 19:54:29 GMT
This one also arises from the first couple of days on the Helmsdale. The water temp of the river was about 33 degrees and the sea temp was around 35 degrees. This was given as an explanation of why there may be few salmon in the river system. (warmer staying at sea.) Question... What length of time could we expect before the temp rises to a more optimum level at this time of year. eg if it was a brilliantly sunny winters day would that have any effect on the temp or would it take two brilliantly sunny days, or more to shift it?? If someone wanted to fish last week in these temps would it have just been a waste of time? Apologies if this is a daft one highlandfisher
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Post by baroness on Jan 21, 2008 20:24:37 GMT
It's not a daft question, but it's not the reason there were no fresh fish in the Helmsdale last week. Over the last 30 years the race of fish that came into rivers over the winter has diminished, almost to the point of disappearing. In the 60s there was a run of fish into the Spey, Dee, Tay and Moriston/Garry part of the Ness system, and possibly other places, that were heading for the hills to spawn. There were also a lot of them on the Beauly and Conon until the Hydro Board built dams five miles from the sea, but don't get me started on that. They ran from late September until early January or so and were the reason why there were good catches on these rivers on the first few days of the season. Where in the river they were varied according to the temperature and water height, but given the time they had to come into the river undisturbed they were usually well spread out. Since then these fish have dwindled. I don't know why, but suspect that it is to do with the generally milder winters we have now compared with the 60s and early 70s. Some survive, but the numbers are a shadow of what was always a small and vulnerable population. That said, once these winter fish are in the river the main spring run does like to hold back until there is a temperature difference between the river and the sea in favour of the river. Why that should be I don't know, it just is. Fish are cold blooded so it may just be a comfort thing, but that leads to anthropomorphism, and we don't want to go there. An example of this is the early run that the Moriston still gets. These fish run the Ness very early, but are rarely caught there. When they reach the mouth of the Moriston, they largely lie in Loch Ness, unless the river water is warmer. I don't know enough about the Helmsdale to say if there ever was a significant run of winter fish, if there ever was I suspect they have gone the way of other river's stock, and that is wht there were no fish last week, and why there won't be a significant number of January fish for a century or so at least.
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Post by builnacraig on Jan 21, 2008 22:19:54 GMT
Highlandfisher,
Can't believe the sea temp is 35degrees. The lowest the open north sea would go is 4-5oC or 39-41 farenheit. The river temp follows the air temp pretty closely so a few mild days will soon get it up to the same temp as the sea if not higher. Sun will take the river temp up but at this time of year that tends to mean frosty weather which will drop the temp like a stone. Mild wet weather will take the river temp up a few degrees in little time. I have had a temp logger in a river in Ayrshire for the last year if I can manage it I will put the data on the forum.
Builnacraig
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hf
Active Member
Posts: 1,807
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Post by hf on Jan 21, 2008 23:23:55 GMT
Thanks for the replies and big apologies on my part, not because of the question but because I got my facts wrong. Builnacraig, thanks for pointing that out about the sea temp. I double checked and realised that I messed up. The figure for the river should have been 35/36 degrees and the sea 2/3 degrees higher than that. (figures taken from R. Sutherland's Helmsdale Company web page.) Thanks though for answering my question all the same. If the weather gets milder I may take another trip up there. Baroness, thanks for your thoughts too and also for the point about the vulnerability of the spring salmon population. highlandfisher
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