Lake Hopatcong Grass Carp:

[Eskimo]

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Apparently this carp will be GMO: They will have three sets of chromosomes (triploid) and will be unable to reproduce in the lake.

They grow quite large and have some value as a sportfish.

[Andrushkin33]

Sleep well my friends.

Couple of Russian buddies from Brooklyn and carp situation will be under control in no time.

Andre

[cosmo]

Introducing an "invasive species" of carp is concerning.

We need to protect those herring and provide the best habitat possible for them to flourish. The entire lake's ecosystem depends upon it. Less weeds, less herring and everything changes, and definitely NOT for the better.

As stated by several above. There is no control once a non-native fish is introduced to the lake. It is counter to every instinct I have as a fisherman.

Googling the topic, I found the following from a Michigan / Great Lakes study, which validates the "nature will find a way theory":

“In the mid-1980s, a grass carp sterilization program was put in place to reduce the risk of introduced fish reproducing and reaching nuisance levels that would result in detrimental impacts,” Herbst said. “The sterilization program has worked to some extent, but fertile fish are still being captured in locations where only sterile fish introduction is authorized.”

[Charlie B]

Better and safer than chemical treatment and less cost than harvesting. I would welcome it...Charlie

[AndyS]

How about stopping all the residents around the lake from using high phosphorous fertilizers that promote weed grow when it washes off their lawns into the lake. The 100 year old septic fields that surround that lake promote weed growth also.
Kill the weeds and all the herring will be gone. Small fish need weeds to hide in as they grow bigger. This idea is coming from a boating, not a fishing community.

[AndyS]

The water quality will go way down if all the weeds disappear.
The Musconetcong river that is fed by this lake will be toast !

[Drossi]

Originally Posted by AndyS

How about stopping all the residents around the lake from using high phosphorous fertilizers that promote weed grow when it washes off their lawns into the lake. The 100 year old septic fields that surround that lake promote weed growth also.
Kill the weeds and all the herring will be gone. Small fish need weeds to hide in as they grow bigger. This idea is coming from a boating, not a fishing community.

Ignore those, they can't be the cause! Been that way since the late 1970's. If they'd taken proper care with the environment the lake wouldn't have the week issue it does. Most boaters aren't fisherman so they won't care if ridding the lake of weeds by any means does damage to the bait fish or other fish populations.

[Chrisper4694]

check out the candlewood lake grass carp introduction. That is why they are considering this, because of the apparent success there. I'm no convinced one way or the other but if you want all the information check it out, that is what they are using as 'proof' it has validation.

[Hookmanski]

I think there are decent arguments on both sides, but I agree that introducing an invasive species into the lake isn't the best idea. I don't know if this would make much difference, but if they could ensure the carp can't reproduce before stocking them that would be the most ideal situation. It could work if they managed it correctly, but if there is no solid way to tell if a carp is going to be fertile or not, then I say don't stock them.

However, if they can be 100% sure they won't reproduce, it could possibly work. How many are they looking to stock? I feel like if you had around 30-50 large carp in there, they could eat some of the vegetation but may not have as big of an impact as say 200. That way some of the weeds could get eaten and some would remain. Kind of a compromise.

Now I'm no biologist here, just giving an idea that could possibly work, making the lake a little better for pleasure boaters while not having too much of an adverse effect on the life in the lake. But like I said, if they can't promise the carp will be sterile, then I'm definitely against it.

[NJSquatch]

What is a Triploid Grass Carp? http://www.dec.ny.gov/outdoor/7973.html

In 1983, US grass carp producers began production of a sterile (triploid) form of grass carp, mitigating the reproductive concerns associated with the diploid fish. Triploid grass carp are created through shocking grass carp eggs immediately after fertilization with either hot or cold water. This temperature shock results in the retention of an extra chromosome set, rendering the fish incapable of producing viable young. With the exception of this extra chromosome set, triploid grass carp are identical to their diploid counterparts. They can live 10 years and grow to 25 pounds.

Triploid grass carp have distinct feeding preferences, preferring tender, succulent plant species over those that are tough and fibrous. Triploid grass carp will not control emergent species such as cattail or bulrush or floating leaved species such as water shield or water lily. Even among preferred submergent plant species, selectivity and consumption rate varies widely according to a vast array of factors including water temperature, dissolved oxygen and presence or absence of attached algae.

Triploid grass carp are extremely potent plant consumers. If overstocked, they are capable of eradicating all plants from a pond for periods exceeding 10 years. Besides the obvious impact such complete plant removal will have on vegetation-dependent fish and wildlife, total devegetation of a pond can also result in the development of severe algae blooms, foul smells and an overall decline in water clarity. To minimize or prevent such adverse impacts, plant populations should be maintained at approximately 20-30% of the pond's surface area.

Due to various factors that impact triploid grass carp feeding, it is impossible to precisely predict the exact number of fish to stock to achieve the 20-30% plant coverage target. The only way to prevent excessive plant control is through use of an incremental approach. This approach involves the stocking of triploid grass carp at the stocking rates suggested below, followed by a two-year waiting period for the fish to achieve maximal control. Then, if needed, more fish are added in small increments at two-year intervals until plant populations are reduced to the 20-30% threshold.

Recommended Initial Triploid Grass Carp Stocking Rates
Average Plant Density / Stocking Rate (# of fish per acre)
Low Plant Density / 5 fish per acre
Medium Plant Density / 10 fish per acre
High Plant Density / 15 fish per acre

Lake hopatcong is around 2,500 acres with approximately 30-40% of that area being less than 15' where the weeds will grow.