Pond Boss Forums Thread Like Summary - Pondweed, chara, vs duckweed

3 years in to my 1 acre, 8-10 ft deep pond. Clarity is good, cnbg/lmb populations are good with 3 lb bass (we are removing 10-20 lbs this year). We have American pond weed around the edges maybe 10 feet out, and then by mid summer, chara reaches the surface and maybe 1/2 the pond is not fishable. Nutrients run in from a nearby cattle pasture. I’m building up the bank plants to help with inflow, but I noticed some duckweed in a nearby swamp area. It may show up regardless of what I do, but I was wondering if duckweed might compete for nutrients with the chara in a balanced way? I’m in Oklahoma with fair wind across my pond…I like the idea of increasing biodiversity in my pond…but most duckweed comments are negative. Thoughts? Suggestions?…

The nutrients from the cattle pasture are the problem. If there was a way to divert those from entering the pond, I would. If you whack back the chara, my bet is that the visibility will decrease and there might be a FA problem popping up too.

The duckweed will compete for some of the nutrients, but I can't say if you aren't jumping from the frying pan into the fire with the duckweed. I have seen it completely cover a pond without aeration, and in a pond that has aeration there were only 10
-15' circles by the diffusers that didn't have duckweed covering the surface.

You can knock back the Chara in the Spring when it is still bright green and vibrant, but later on in the year as it matures it will be harder to control. You will also be controlling the APW if you have to control the Duckweed, as the majority of chemicals that affect duckweed also affect APW..

pdubdo,

I would very much prefer chara over duckweed. The trophic stage of your pond might not support duckweed at this time.

Chara love limey soils and commonly occurs where I grew up in Oklahoma where there is limestone outcrops locally. Chara is an interesting macro algae that is symbiotic with periphytonic blue-green algae that fixes nitrogen. It is actually very important to maintaining the fertility of some rice paddies that have been in production more than 2000 years. It is also a very good plant to have if you want to establish PK shrimp providing both food (periphyton) and cover for them.

If I had this problem, I would probably consider ways of intercepting nutrients as esshup suggested, I would stop feeding if you happen to be doing that, I would introduce PK shrimp, and finally I might build a 1/20 acre forage pond to raise crayfish. I would seine the forage pond once a year and put them all in the main pond as forage that would shred and consume the Chara. They are great forage. It would work like this ... they would have cover and grow when there is plenty of chara ... as they deplete the chara they will be exposed to predators (so will the PK shrimp). Treat it as an annual cycle of growth and consumption.

Harvesting fish is a great way of removing nutrients but it can be kind of slow if its LMB and BG that your are harvesting. You might reasonable remove around 60 to 75 lbs/acre maintaining balance but the dry weight of those fish are only 12 to 15 lbs/acre. So its easy to see that if one harvests like that while feeding 50 lbs of formulated feed a month for 5 months a year that he is adding nutrient dry weight up to 20 times faster than he is taking it out.