|
|
Post by nige_LS7 on Feb 19, 2015 15:35:59 GMT
Fishing below Skelton weir on the Aire the other day, we noticed that small branches we snagged and reeled in from below the surface were entirely covered in thousands of squirming larvae ... one branch was about 5 foot long and still every millimetre of its surface was covered in them ... not seen anything like that before. My Mrs isn't normally squeamish about maggots or worms or anything like that, having grown up as part of a fishing family, but she was a bit disgusted by this lot, and when she changed swim she said that even bits of weed she reeled in were covered in the same pale larvae, bit smaller and much thinner than bait maggots. Had a decent chub from the swim but I'm not sure I'm going to be able to persuade her to go back there again, to be honest I'm not sure I'm that keen to now either, as let's face it the banks look as if they are half built from stuff that's been through the sewage system , and it's not as though the nearby motorway makes it a tranquil rural idyll either. Anyway back to these larvae - are they a sign that the river - which was clear and low of course as it has been lately- is dirtier than it looks on the bottom? I suppose these larvae are normally a jolly good thing, eating algae and providing lots of fish food, but is it normal that everything under the water is covered in them like this swim was? And in February? Anyone know ? Can post a picture of them later from her phone (if you like slimy larvae pics  ) |
|
|
|
Post by gcb on Feb 19, 2015 19:24:27 GMT
Hiya mate. I am a volunteer sampler for the riverfly partnership. We check the distribution of invertebrates as a guide to the health of a river.
We record the frequency of 8 different groups which are particularly susceptible to pollution so we can pick up signs that may damage a watercourse but may not be visible to the human eye. Send me a picture of what you found and I will try to identify it for you. Many nymphs will be in the water for at least a year so they are abundant even in winter.
geoff
|
|
|
|
Post by nige_LS7 on Feb 19, 2015 19:45:59 GMT
Hiya mate. I am a volunteer sampler for the riverfly partnership. We check the distribution of invertebrates as a guide to the health of a river. We record the frequency of 8 different groups which are particularly susceptible to pollution so we can pick up signs that may damage a watercourse but may not be visible to the human eye. Send me a picture of what you found and I will try to identify it for you. Many nymphs will be in the water for at least a year so they are abundant even in winter. geoff thanks Geoff. Here's some of the vegetation we pulled out. Does this enlarge when you click on it?  |
|
|
|
Post by gcb on Feb 19, 2015 20:44:38 GMT
It does but I would like to pass it on. Can you provide a larger image for me to work with ? My first impression is that these are probably of a sign of a healthy river rather than a polluted one especially as they have come from below a weir which is usually an area of well oxygenated water.
|
|
|
|
Post by Eddie on Feb 19, 2015 21:19:02 GMT
Geoff, if you click on the image it is expandable, might give you more idea. Rather than insect life, could be water snail larvae maybe or something similar. Would that be likely below the outfall of a sewerage plant?
Eddie.
|
|
|
|
Post by nige_LS7 on Feb 19, 2015 21:29:22 GMT
It does but I would like to pass it on. Can you provide a larger image for me to work with ? My first impression is that these are probably of a sign of a healthy river rather than a polluted one especially as they have come from below a weir which is usually an area of well oxygenated water. yes, it was a swim that was recommended on here (3 years ago) as being the best for miles and when I saw it I thought it looked healthy. First deep water after about 200 yards of shallow water after a weir. Just never seen anything like it before when EVERYTHING we pulled out was covered in slime & these things! Had to crop it to get it to the 1 Mb limit for this site, so I can email you the wider picture but I don't have anything more close-up or higher resolution I'm afraid. P-m me your email address? |
|
|
|
Post by gcb on Feb 19, 2015 21:35:19 GMT
E mail would be good - where is skelton weir ? I know the riverfly co-ordinator for the Aire. I'm sure she would be interested in the pic. It is monitoring like you have done that is vital in protecting our river habitats. If you or anybody else would like to become involved in protecting our waterways by monitoring river invertebrates see riverflies.org on how to become involved. The more citizen scientists the better !
|
|
|
|
Post by gcb on Feb 19, 2015 21:44:51 GMT
|
|
|
|
Post by nige_LS7 on Feb 19, 2015 21:53:33 GMT
E mail would be good - where is skelton weir ? I know the riverfly co-ordinator for the Aire. I'm sure she would be interested in the pic. It is monitoring like you have done that is vital in protecting our river habitats. If you or anybody else would like to become involved in protecting our waterways by monitoring river invertebrates see riverflies.org on how to become involved. The more citizen scientists the better ! I'll have a look at that website sure enough. A quarter of a mile downstream from Thwaites Mill there's Skelton Grange Bridge, and another 600 yards down (past the vast Knostrop sewage site) there's the weir, then 200 more yards to this swim. I found a post from Frim where he said that sewage discharge could be a factor in this swim. The banks themselves tell you that it has been, though as I say the water seemed clean when we were there. p-m me that email address. |
|
|
|
Post by gcb on Feb 19, 2015 22:04:17 GMT
There are heavy fines now for anybody or organisations who are polluting our watercourses-sewage site or not. The riverfly partnership has been responsible for securing several prosecutions. The more that these companies are aware that monitoring is going on the less likely they are to send pollution into the river.
|
|
|
|
Post by rickyg on Feb 20, 2015 9:33:10 GMT
the weir you are talking about is not below any sewage outfall. The weir is below the old power station outfall, you will see it 100metres or so above the weir on the far bank.The sewage (treated?)runs from the works along a constructed stream with various sills to oxygenate the water.This stream winds its way from the sewage works and enters the Aire 400 metres below where the M1 crosses the river. You may have noticed 2 concrete half moon bridges as you drive south, there is a weir below these and the stream from knowstrop enters below here.I have fished further downstream, if you hook a peice of weed or cloth it is crawling with bugs,some look quite prehistoric, I think the river is very clean down there,the margins are solid with minnows in the summer, and the fish population has changed over the years from "dirty" water fish like roach and gudgeon, to mainly dace and evev trout
|
|
|
|
Post by nige_LS7 on Feb 20, 2015 10:15:38 GMT
the weir you are talking about is not below any sewage outfall. The weir is below the old power station outfall, you will see it 100metres or so above the weir on the far bank.The sewage (treated?)runs from the works along a constructed stream with various sills to oxygenate the water.This stream winds its way from the sewage works and enters the Aire 400 metres below where the M1 crosses the river. You may have noticed 2 concrete half moon bridges as you drive south, there is a weir below these and the stream from knowstrop enters below here.I have fished further downstream, if you hook a peice of weed or cloth it is crawling with bugs,some look quite prehistoric, I think the river is very clean down there,the margins are solid with minnows in the summer, and the fish population has changed over the years from "dirty" water fish like roach and gudgeon, to mainly dace and evev trout Great this is what I wanted to hear - many thanks for this. I was exploring all down there last week and had the impression the water was clean and healthy, though you do see sanitary towels etc in the silt on the banks which must be signs of sewage overflow, But then fished it two days later and when everything was crawling with the same larvae I just wondered. The Mrs is really keen to find out what they are! I searched on here and in the same swim a few years back Frim & a pal caught some massive trout when he said that "there was a foot on and sewage", so I wondered if that was a factor. But you've put my mind at rest there. thanks Ricky. So The Wyke Beck carries the treated sewage eh - its obvious on google earth now you mention it. |
|
|
|
Post by rickyg on Feb 20, 2015 10:51:37 GMT
the river seems to get sewerage in when we have the short torrential showers,the storm drains can not cope resulting in sewerage going straight into the river. The calder is even worse, but that is the risk as the river is flowing through a built up area with no natural run off.If these events occur in summer when the river is low and de-oxygenated the sewaged could further de oxygenate the river resulting in fish/ invertebrate kills. There have been isolated incidents around leeds in years gone by. but unfortunately there is nothing you can do about it
|
|
|
|
Post by flylife on Feb 25, 2015 9:36:17 GMT
Look like Ryacophila to me, caseless caddis, the pupae of caddis fly/sedges
|
|
|
|
Post by grayson on Feb 25, 2015 11:37:16 GMT
The average fisherman rarely thinks about what lives in rivers; and nor did I until I got involved in monitoring fly life on various waters. Utterly fascinating - and regular sampling will tell you far more than anglers' anecdotes about the the health of a river. I regularly sample one small river where in a 2 minute kick sample we can get 1000plus nymphs . Don't think this is only about flyfishing either - the invertebrate life is the basic building block of life in your river.
|
|
)
