Small pond covered in surface weed

[no-one in particular]

This little pond is in a beautiful spot surrounded by fields full of wildflowers. Which is why I was there plus a nice pub nearby with spectacular views across a valley.
However, it was covered in surface weed. I knew it held some very small rudd many years ago. Its only about 2 or 3 foot deep. Would the fish survive with all that surface weed, will it have killed the natural weed underneath which as I remember there was a lot of that - and would it kill the fish?

 

[108831]

It certainly is not healthy and will kill the weed below due to light depravation,invertebrate life will probably suffer too,because of the loss of normal weed,I would imagine the stuff on the surface could possibly be algae,can't really see from the picture...

 

[The bad one]

Could be algae or it could be duckweed, Lemna minor, can't tell from the photo. Cutting off it's light supply with black plastic sheeting or chemically treating it with an aquatic herbicide will get rid of it.

 

[no-one in particular]

All I know it did part when some ducks landed on it, you can just see the hole to the right. So, it looked like surface stuff, I think it was more like a weed than algae.
I will have a closer look and better pic if I go up there again. When the ducks landed could not see any below surface weed which was there once a long time ago, maybe 10 years.

 

[mikench]

It could be accumulated fluff, seeds, willow seeds etc ie general flotsam and jetsam! Quite how you would clear it is a mystery but you could try with a rake in one corner and then put in some bait and a line to see what happens ! If there are fish you could then try removing the lot with a rope/rake or whatever may be better.

 

[103841]

My local estate lake suffers from a lot of surface debris being treelined and with various shrubs all around the perimeter. With a decent breeze it drifts to one end, that’s when I go to work with a large fine mesh landing net and scoop out as much as possible.

 

[seth49]

Where I fish we get a lot of fluff, seeds etc of the willow trees, I discovered a couple of years ago, that a egg cup full of hemp oil, poured on the water, opened up a big clear area to fish in.

It’s marvellous to see, it clears it like magic, the oil spreads on the surface and takes all the fluff etc away.

Can be bought at Tesco’s as good oil, about six pounds for half a litre.

 

[Another Dave]

Could be algae or it could be duckweed, Lemna minor, can't tell from the photo. Cutting off it's light supply with black plastic sheeting or chemically treating it with an aquatic herbicide will get rid of it.

Something's off with the pond if duckweed is multiplying quicker than ducks can eat it.

 

[Another Dave]

It's not fairy moss is it?

 

[108831]

I wonder why,or how it does that Seth?

Never heard of that stuff Dave....

 

[seth49]

Not fully sure, it seems that the oil spreads out on top of the water, and pushes the fluff etc away.

It’s quite safe, carp anglers use it a lot, I like to add it to pellets or groundbait when fishing, you get little drops of oil coming to the surface, when fish start feeding on the bait, hopefully just before you get a bite.

 

[no-one in particular]

I will go and have another look see if I can get a sample and chuck some bread in and see what happens. I dont think a net would help, the ducks landed on it and created quite a large hole but it soon closed in again.

 

[108831]

Just needs cleaning off regularly probably,you often find however that once a water gets infested,it's hard to get rid,other than chemically.

 

[The bad one]

If anybody/club is considering treating a water chemically, you need the qualifications to carry it out. That being PA6W certificate and to notify the EA that you are doing it and where. The equipment the EA use to detect pesticides, herbicides, etc, can detect such substances down to 1 part in 50,000. So any clandestine use if looked for, can be found by their detection equipment.

My advice for chemical treatment of any weed, is to seek advice from the professionals who's business does it day in day out.

 

[theartist]

From the description it looks like duckweed, and where it blocks the light long term it does cause problems, I've also found a connection with blackspot on roach and rudd with duckweed. Putting any sort of oil in such a pond could also be detrimental if the oils contain nutrients, any nutrients added to a pond so small could lead to an explosion of weed and algae.

 

[Another Dave]

I wonder why,or how it does that Seth?

Never heard of that stuff Dave....

The farm pond i fish used to be completely covered in it, it looked like you could walk out on it, only fishable when the wind pushed it to one side. The pond itself was clogged with fallen leaves and had deep black silt choking it up. It's since been restored which is how i can fish it now. I think the fairy moss is one of the last stages in a pond's life; small ponds do tend to fill up with cr@p if left to their own devices and a really high level of nitrates and associated waste chemicals is what that 'moss' needs.

 

[rich66]

Can’t you add lime to a pond to break down the detritus?

Oils a bad idea on a large scale, it will form a barrier between the water and the air and stop the exchange of gasses within the pond.

 

[Another Dave]

No amount of lime or chemicals is going to change the fact that there is a huge supply of nitrogen waiting there ready to grow plants.

 

[Philip]

I dont think anyones anwsered the underlying question which is whether there will still be fish in there ?

I recon yes and probably more than would be first imagined.

 

[no-one in particular]

I think I found the answer to that Phillip. Stumbled across the owners and they let me take some pictures. The pics dont show up the results very well as the original one didn't. But I got closer and took these. It does look like a surface scum sort of algae as the bad one suggested, very thin and looks a bit greener than in the pic.
However, the owners said someone had put two terrapins in there and they ate all the fish. I did not know they ate fish and would have never guessed that would be the outcome of my investigation! I did not notice any weed either which as I remembered it once had loads of it sticking up on the surface. I chucked a bit of bread in between the trees in the clear bit anyway and nothing came and nibbled it after about 15mins.