The big question is that what the damages did the northern snakehead caused? I do not see any proof that they did cause the damages to the ecosystems. Funny thing is that before the discovery of Crofton Pond snakeheads, we have snakeheads in the waters already for many years but nobody say anything about it.
Hence, when the East Asian market owners decided it was prudent to go into extreme mass hatchery mode to enable them to increase the supply and match the demand, they asked for "permission" instead of the small scale stealth "stockings". That is what "tipped off" the officials to the Northern Snakehead in Maryland waters.
East Asian markets that sold live fish in their market including Northern Snakehead in the Maryland and D.C. area were certainly not limited to the "Crofton Area" only. They are still very common throughout D.C. and surrounding Prince Georges County, MD.
Please don't tell me that you fell for the manure story that it was irresponsible tropical fish keepers that threw a handful of pet Snakeheads into a Crofton pond and the Frankenfish were able to walk 17 miles to establish a major viable population of Snakeheads (easily numbering in the 10's of thousands now) in the Potomac River? I guess I have to give these frankenfish credit where it is due. The were smart enough forgo a much shorter 5 mile journey to establish themselves in the breathtakingly beautiful "scenic Severn River".
This river has extreme wealth living along it. Not many East Asian markets and the Scenic Severn would provide accessible harvest areas due to the Human population inhabiting the land around the tributary.
There was NOT 10's of thousands of Snakehead in the Potomac before the "tip-off" on the Crofton pond. There is no way that a 20 year period is going to show any damage to the ecosystem without being undeniably critically invasive species.
We are 10 to 20 years away from even attempting to responsibly answer the question of "what damage have the Snakeheads caused".
You coming off as the type that will deny that water is rising until you have drown! If twenty years from now, no other species exists in the Potomac, you would still no doubt not give an inch and still claim that it had nothing to do with the poor ole Northern Snakehead!
I will however give you an acknowledgement that in the short duration of years that we can count on our fingers and toes, there is no indisputable factual proof the the Snakehead is "damaging" the ecosystem in the Potomac. As much as I despise the authorities for lying like a wet rug to the public involving the Nothern Snakehead, I can easily understand their concern.
Some of us are not myopic enough to enjoy a comfort level with this introduced species (Notice I did not use the term "invasive" at this point!) prolifically breeding in the Potomac.
Lets go over some "traits" of the Northern Snakehead that puts it in an advantageous to either the native fish population, or the previously introduced fish populations currently in the Potomac.
1. Parental care for the fry. (The Snakehead seems to have a far greater sense of responsibility as a species for protecting and raising the newly hatched Snakeheads than any of the other "predatory fish" inhabiting the Potomac.) The adult Snakehead parents are both willing to fight to the death to protect their fry from potential prey, and easily capable of successfully defending their fry from any other predator in the Potomac.
2. Duration of fry protection. (The Snakehead definitely remains in diligent protection mode of their fry far longer than any other predator fish in the water.) They are as a rule raised to a large enough size that this these tough juveniles can defend themselves against the majority of the predatory fish in the body of water. Their fry to adult ratio is most likely light years beyond that of the other predatory fish in the Potomac. It will be telltale in 50 - 100 years or will be PROVEN insignificant at that time.
3. Cannibalism - The Snakehead is most likely the predatory species in the Potomac with the lowest incident rate of cannibalism within it's species inhabiting the Potomac. They are therefore the least likely predatory species to "manage" overpopulation within their species. This is possibly the biggest advantage that they have. Not only don't they have to win any form of species war against any of the predatory fish species in the Potomac, they can simply consume masses of safe bream and allow the other predatory fish species to co-specific aggressively further reduce their population. This could be a vicious cycle that continues building upon itself until the damage is irreversible.
4. Human intervention - The "kill" a snakehead" movement for recreational fishermen in the MD. and D.C. area is a joke. (I think we both agree!) With the genius authorites in my area, that have banned the sale of the Northern Snakehead as food have completely removed the entire "commercial fishing fleet" from human impact on the species. We recreational fishermen will be removing a few hundred snakeheads from the water, and in the mean time, the commercial fishing fleets will be measuring the catch of the other "alpha" predatory species (Striped Bass) literally by the TON! Holey F' if you can't see this as THE downfall. At least they should feed the poor with Snakehead if they cannot build a major market for the meat of the Snakehead. The Commercial fishing fleet no doubt will easily be able to do 10x the impact on the snakehead population than can we!