Pond Boss Forums INTRO Questions & Observations Has Anyone Seen Success with Grass Carp?

I've posted before how discouraging it has been that I stocked too many triploid grass carp (180 in a 6 acre pond). The first 10 years or so the water looked pretty good. There fewer and fewer weeds and algae each year, and the water was relatively clear. Now, 20 years later, the water becomes greenish-brown when late summer arrives. A secchi disk disappears totally at 22". The GC have eaten every bit of rooted vegetation leaving only an overabundance of phytoplankton to take up the nutrients and turning the water cloudy. Much to my dismay, the grass carp don't ever seem to die.

I've recently read where the ideal number of GC is almost impossible to achieve. Either they are under stocked and the weeds aren't controlled, or they are overstocked and green water is the result.

I would be very interested if anyone has seen just the right balance after GC were in a pond for more than 10 years. A perfect balance for me would be moderate weeds and algae and nice clear water. Are there any success stories out there?

Grass carp are not legal in Michigan. But at the Lake Leader Institute the fish professor showed a photo of them, (I was the only one who could identify the fish, ya!). I asked him if they work, and he said yes. That is all I know.

I put 12 in a 6-7 acre pond about 5 years ago. They do a good job of keeping weeds from getting too out of control.

They are all over 3' long now.

I have had 5 in something under an acre for 6 years now. There is a little potamotagon (sic) pond weed and arrowhead next to the shoreline (shallower parts), and that is it for plants.

FWIW, they run 3' - 3 1/2' long, and weigh in excess of 40 pounds.

Theo, that's sound perfect. I hope it continues.

Sunil, a dozen GC sounds too few, but evidently it isn't!

2catmom, I wish that professor could see my murky water!

Mine did a good job while they were young (up to 4-5 lbs) then they seemed to get lazy and were first in line at pellet time.

They have worked everywhere I have stocked them.

Lynda,

You're DNR doesn't allow them because they are afraid they will go where they are not supposed to be and decimate native vegatation. At the same time they say they don't work. Sounds to me like someone is trying to have it both ways.

What's really interesting is an MDNR person spoke at an aquaculture meeting I was at and said their digestive track is so short the vegatation they eat just shoots right through virtually undigested.

Here's the digestive trac of a grass carp. Does this look so short to anyone here that the vegetation shoots through virtually undigested? Or perhaps it is a relative thing and this is short for a fish that specializes in vegetation?

Sandman,

Sounds like you overstocked.

Looks like deer guts! HAHA Coincidence?

sounds like it is time to do a little bowfishing, you have way too many judging from what the experts say to stock.

I put 5 in my pond this year in May as Theo said my pond is also a little under 1 acre. I have not seen any difference this year but I was told that would be normal. I am interested to see if this spring they keep up??? Since I put them in there in may I have not seen them, but I have quite a bit of Chara and pond weed so there is a lot of places to hide right now.

RC51

Good lord Cecil, how about some "Explict Photograph" warning. Jeez, I'm gonna be tasting coffee all day.... must think happy thoughts....must think happy thoughts....must think happy thoughts.

I stocked 3 in a 1 1/2 acre pond. Figured better to go on the low side and add if needed. Not much noticable the first year. Water more clear this year. Very little vegatation in the pond and what there is they have pretty much kept to the shorline. They look to be about 3 foot now and are very healthy. Caught one by accident catfishing the year after stocking and he had grown from a 10 incher to about 2 foot.

RC51 and Jeff, Please don't do what I did! Give the GC a good while to show their abilities. I didn't start to notice any results until after the third year. The first 3 years I continued to stock more GC because I was anxious to see results. As a consequence I really over stocked as others here have noted.

It wasn't until the 10th year or so that all the vegetation was wiped out and the water became greener each successive year. Everyone here is cordially invited to come over and bow fish!

Cecil, You and gallop are right, I really over stocked! I never heard that one about the short digestive tract, but it sure looks like you vividly refuted that proposition.

To dispel another notion, GC continue eating through out their lives no matter how old they get. I've heard it said that after they reach a certain age they don't eat any more. Nonsense! My GC are 20 years old. You should see them pulling weeds along the shore when the water is high after a storm. They even start plucking off the leaves of willow trees that happened to touch the water. This year I planted a large water lilly, one of their least favorite foods. After ignoring it for two weeks they finally ran out of other grub and ate it up in a few bites.

Sandman,

Thanks for the advice. I will TRY and keep my patience about me. Those dang weeds though will drive a P.M. CRAZY!!!! Or even a rookie like myself! I will wait and see. The local pond stocker guy told me I needed 8 in my pond but I went with 5 as I want to control my weeds not destroy them!

RC51

Jeff suck it in and be a man. I know you're from California but...

Hey, those are my guts!

I recognize my hand, my watch, and my cleaning board and my fish cleaning station tractor front-end loader.

Ken

Jeff you left out the grin emoticon when you quoted me. Makes all the difference.

I knew i got it from somewhere! I hope you don't mind.