Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Water net (hydrodictyon)

New to board.
Having a terrible problem with waternet in our production ponds.
If we use enough product to kill the water net,we kill the bloom.These are production ponds,so that's not acceptable.Has rapidly spread from pond to pond,I believe by geese,etc,as we are very careful about nets,boots,etc.
It starts at the bottom,then explodes,winds up top to bottom,gilling all the fry/fingerlings.Then it dies off,forming giant floating mats,with netting hanging down in the water column,gilling anything swimming.
Anyone have any experience with this?

Is waternet filamentous algae?

Bruce it is a type of FA.

Welcome JHM to the PB forum. Some additional info may help us all to give input. What part of the country are you in and what are your soil/water conditions?
Here is a link on FA including water net and one on FA from TAMU.

http://plants.ifas.ufl.edu/guide/2algae.html

http://aquaplant.tamu.edu/database/algae/filamentous_algae_mgmt.htm

And look at this PB post for a possible idea if your conditions warrant. But be careful if you decide to try it.

http://www.pondboss.com/ubb/ultimatebb.php?ubb=get_topic;f=14;t=000228;p=1#000000

MidAtlantic area,relatively shallow ponds for production of fry and fingerlings.Usually multicrop each pond:up to 3 times per year each.
Water is pretty hard (120-150),and pH is always on the high side.Out of the well it's 8.3,add a little fert/soybean meal and up she goes,but we've learned to control it with gypsum applications.Don't want to risk raising it much higher.Have used hydrated lime in the past to deal with clam shrimp.
We seem to have two distinct types of water net.One has a very small mesh,and the other is 1/8-3/16" openings.PERFECT for entanglement/gilling of small fish.Mesh size is not related to age of algae.When this stuff comes on,it COMES ON! Is becoming a problem in a growing number of places,and I'm seeing it listed in more and more lists of invasive and nuisance species.

Tentative plan is to hit it just before initial fill next spring with granular Cutrine-Plus,and hope that the concentration at the bottom/water interface remains high enough to be effective on the hydrodictyon,and yet still allow phytoplankton/zooplankton to thrive elsewhere throughout the water column.
We've been fooling around with spot treatments,varying app rates,timing,etc for the last few years.We can kill it.Just can't produce fish in the ponds then.If it takes a year of going nuclear and forgoing production,well then,that's what we'll do.Will have to hit every pond at once,as it's so easily spread.

What about manual removal by using a strong net or rigid plastic netting.

If you try manual removal,you'll entrap/entrain every fish/fry/fingerling in its path.
And it'll be back the next day.
I've been in the biz a long time,and have learned to deal with most everything,but this is some BAD stuff.
New Zealand had horiffic blooms of it-birds would nest on it.Wisc. also had troubles in the 30s and 40s.
Ours seems to act a little different from all the lit I've read.

Brings to mind the old saying,

"Too thick to swim,too thin to plow".