# Good quote on Grass carp



## [email protected] (Dec 22, 2006)

I thought this was worth posting because I think he pretty much hit the nail on the head.

From article in Progressive Farming magazine:

"Chris Larson, a fisheries biologist with the Iowa Department of Natural Resources, says carp have little or no impact the first few years. But later, if they were overstocked, they can be too effective and remove most or all vegetation.


The proper stocking rate is two to three grass carp per acre, he stresses. "And be patient," he explains. "It may take three to five years for those fish to reach sufficient biomass to control vegetation."


----------



## Eugene (Jun 23, 2004)

Indeed! I can't tell you how many ponds I've seen where impatient owners/managers stocked the recommended number, and then--not seeing immediate results/not receiving immediate gratification--tripled that in a few months. The eventual result is a scoured, muddy hole with dozens of carp mouths sucking clippings at the surface whenever a lawnmower passes.

Once too many are in, any carp spp. can be kind of tricky to remove. They are pretty sensitive and tend to avoid electrofishers and standard net gears. They can be susceptible to traps incorporating flow, but those are pretty specialized and tend to be labor intensive. Bowfishing in season can help.


----------



## Fishman (Apr 5, 2004)

It's completely inaccurate in my views. Every pond and lake is different, who can argue that? I'de tell Chris Larson the proper stocking rates vary just apon that and nothing more and nothing less based on the above statement. I'de hope coming from a state fisheries biologist you accidentally misquoted him.

Some ponds need zero per arce. Some need 30+. It's really quite variable for the obvious reasons. General industry recommendations tend to be on the high side, but again it's general. Your average pond owner wants a pond they can enjoy recreationaly with minimal effort on their behalf and that generally means zero vegetation. 

Eugene, quite the doom and gloom senario you painted there of "carp". We're talking about Amur here not common carp. I've never seen a body of water muddied by amur UNLESS they we're spooked or feeding aggressivly in the shallows, and by aggressivly I mean thrashing about wildly. I frequently watch amur swim around in 6" or less of water feeding and they really move quite slowly. Their vegetarians isn't like they have to move fast to get a meal. It's only when something spooks them they make a big muddy swirl.... even with that it's not going to turn a pond into a "muddy hole." 

As far as them being tricky to remove via "ectrofishers or standard net gears." I'm fairly certain most guys arn't going to use those methods  There's a good likley hood that anyone whom is concerned with the ammount of amur in their pond also pellet feeds their fish. Anyone who pellet feeds and has amur know's they'll take the stuff although they're a little shy about it. Simply make a dough ball out of fish chow and float it out there amongst all the pellets, pull it away from non-target species and let the amurs inhale it. If you really want to get technical there are a lot of other baits that work well, but again if you're really managing your pond theres a good likley hood you're a pellet feeder.


----------



## valeriec (Feb 9, 2008)

I have to agree with Fishman. I urge pond owners to consult our Ohio State fisheries biologists for proper stocking rates and their position on grass carp (triploid white amur) stocking IN OHIO. Proper stocking rates depend on the amount and kind of vegetation in the pond. Grass carp are less affective at controlling certain types of vegetation, but VERY affective on others. The Ohio Pond management handbook recommends 10-20 per acre and says do not expect them to solve problems over night; it may take them a year or two to control vegetation. I believe that it is more about pond owners expectations and obtaining the correct stocking rates. 

Valerie
Aquatic Biologist, ATAC
1-888-998-POND


----------



## valeriec (Feb 9, 2008)

Here is a link to a publication about with more information about grass carp. It gives information on correct stocking rates based on the amount of vegetation, their preference for certain plants and algae, the amount of vegetation they consume with age, and the affects of water temperature on their consumption rates. ATAC bases our stocking rates on this publication and those recommended by ODNR.

http://srac.tamu.edu/tmppdfs/294606...77AEA9956F3CB&jsessionid=8e30d64e3fbe7f295b93


----------



## Eugene (Jun 23, 2004)

I don't think anybody is disagreeing here. Of course, I know exactly what grass carp/white amur/_Ctenopharyngodon idella_ are. I even know what triploid/triploidy means...and the differences implied between the terms "carps" and "carp." Of course, every pond is different and different vegetation assemblage structures require different approaches.

"Spp." is a common abbreviation amongst biologist types to refer to "species" in plural ("sp." Is the singular form). Thus, when I was referring to the trickiness inherent in collecting carps (i.e., "carp spp."), I was addressing carps in general, be they grass, common, black, silver, what-have-you. As a group--i.e, the big minnows of Asian/Eastern European origin--they do tend to be. Of course, those gears to which I referred are types employed by professionals in agencies or pond management (like Valerie), not necessarily by pond owners themselves.

In referring to a "scoured, muddy hole", I wasn't necessarily referring to turbidity/suspended solids within the water column, but to bare, vegetation-free substrate (thus the "scoured" part)...although, depending upon fetch conditions, removing all vegetation can destabilize flocculant substrate and allow wind resuspension of substrate to the water column. I even published a paper to touch on that [if you're a severely nerdy fish nerd, see Hydrobiologia 490(1-3):11-21].

I actually was describing a scenario that I have seen too many times: impatience leading to more grass carp (this time, white amur in the specific) being stocked than were needed to meet a pond owner's management goals. This largely is in reference to ponds maintained almost strictly for traditional bass-bluegill recreational fishing. Such ponds often are not supplemented with pellet feed because, as you say, the desire is to maintain such a fishery with "minimal effort on their behalf", at least regarding physical labor. If you want such populations to be self sustaining and self regulating--and thus to feature a reasonable degree of self recruitment--some amount of vegetation is good for those species. No vegetation (or no cover) at all can lead to recruitment problems; too much can lead to growth problems. It all depends upon the management goals of the owner.

The bottom line, I don't see anything inaccurate in any statement made in this thread. As is usually the case in fisheries management, the one universally correct answer is "it depends."


----------



## Eugene (Jun 23, 2004)

PS: Again, the text is very basic, but it tends to be a good reference for many common situations to many of Ohio's most common management regimes on recreational fish ponds. Here's the Ohio Division of Wildlife's generic take on vegetation control via _C. idella_:
http://www.dnr.state.oh.us/wildlife...ioncontrol/tabid/6237/Default.aspx#biological


----------



## Fishman (Apr 5, 2004)

I know you know your stuff, the orginal post just seemed cut and pasted  It was a bit vague too  I just wanted to put it into a different perspective is all so that an average joe would be able to understand. 

Again, if pond owners want to keep it simplistic they can stock amur at high enough rates to "scour" or "completely keep their pond free of vegetation." Depending on how much time one can afford putting into their pond, and it was just strictly a recreational pond and not one with goals put forth by the pond owner I'de simply recommend appropriate structure to take the place of of the vegatation. Sure, there are *a lot *of added benefits of having actual vegetation in a pond, but with it often comes some work. Most pond owners have a set it and forget it attitude. Ya gotta remember most of us here are, as you said it best, are nerdy fish nerds


----------



## [email protected] (Dec 22, 2006)

From Eugene's DNR link:

"Grass carp stocking rates vary depending on the amount and kind of vegetation in the pond. For ponds with a surface covered by more than 60 percent vegetation, stock them at 10 fish per acre, but reduce the rate to 5 fish per acre for ponds with 40 to 60 percent vegetative cover, and to 2&#8211;3 fish per acre for ponds with 20 to 40 percent vegetative cover. Grass carp are not recommended for less severe problems. More fish can be added if these stocking rates do not provide adequate control. Wait at least three years after your initial stocking before deciding if you need more fish. Grass carp may not be effective for controlling milfoil, water meal, filamentous algae, or Grass carp stocking rates vary depending on the amount and kind of vegetation in the pond. For ponds with a surface covered by more than 60 percent vegetation, stock them at 10 fish per acre, but reduce the rate to 5 fish per acre for ponds with 40 to 60 percent vegetative cover, and to 2&#8211;3 fish per acre for ponds with 20 to 40 percent vegetative cover. Grass carp are not recommended for less severe problems. More fish can be added if these stocking rates do not provide adequate control. Wait at least three years after your initial stocking before deciding if you need more fish. Grass carp may not be effective for controlling milfoil, water meal, filamentous algae, or pond lilies"

From my perspective, the average recreational pond doesn't have 60% vegetation but armor have their place. It is much more practical to kill off unwanted vegetation then stock 2 to 4 per acre to maintain the desired amount of vegetation. Grass carp will eat new growth before old a lot like how horses and cows will graze a mowed portion of pature rather than the tall grass. More armur can be added a few years after if needed. Young grass carp are more effective than old ones so having 2 or 3 age classes present makes much more sense than 20 30lb fish or 600 total pounds of armur per acre at the end of their life cycle. Grass carp are pretty selective at what they eat too. They should be considered a control tool, not an elimination tool.

Tilapia are better.


----------

