Invasive fish — heading here to destroy

By Timothy Joseph, PhD
Fishery Biologist

The “invasive” Silver Carp (from Asia) have overrun most of the Mississippi and Ohio River watersheds.

They have occupied the Tennessee River as far upstream as Wheeler Reservoir in Alabama, and may already be in Guntersville Reservoir. They are heading this way.

Silver Carp can live 20 years, grow to four-feet and weigh 90 pounds.

A mature female will lay 4-5 million eggs each summer, thus they quickly take over and out compete native fish species.

These invasive fish consume massive quantities of phytoplankton and zooplankton, the bottom (foundation) of the food pyramid in every lake, and thus devastate the food supply for all other aquatic organisms including forage and game fish.

When Silver Carp are startled by a passing watercraft, even from rowing, they all panic and jump 6-8 feet high.

This behavior makes waterskiing, wake boarding, jet skiing, tubing, fishing, and traveling in an open boat extremely dangerous, and has resulted in serious injury (broken jaw and fractured skull).

One can only imagine traveling through a wall of heavy, airborne projectiles, let alone pulling a child on a tube.

Economic impacts include tourism revenue losses to marinas and many small businesses.

Fishing tournaments will slowly disappear, for the population and health of game fish will be severely reduced.

Property values will drop significantly, along with property tax revenues to the counties and state.

These losses will amount to hundreds of millions of dollars each year.

It is possible to prevent migration of these fish upstream by installing electric barriers, a proven technology.

They have been installed in many locations in the U.S. and Europe, and have been in use since the 1950s.

These electric barriers are installed in front of locks to prevent the fish from entering the lock.

There is no danger of electrocution if someone fell in the water, for the pulsed DC voltage is extremely low .2 to 1.2 Volts.

A sonic/sound barrier is another technology, but only about 90 percent effective.

The estimated cost to install an electric barrier on a typical TVA lock is $10 million.

However, one must take into account that the Tennessee River brings in $12 billion annually and local economies average one-million dollars of economic income per mile of shoreline.

Watts Bar Lake has over 722 miles of shoreline, thus $10-million is but a small price to pay to protect this economic engine.

There are many ways funds can be raised to pay for this protection.

Because they are in Wheeler Reservoir, and the time to design and construct barriers is two to three years, the silver carp will most assuredly have reached Guntersville Reservoir.

Thus, electric barriers absolutely must be installed as soon as possible at both Nickajack and Chickamauga locks.

Once complete, an electric barrier must then be installed at the Watts Bar lock.

Only in this way can we do everything possible to protect the upstream lakes/reservoirs. These efforts need to be undertaken by the Tennessee Wildlife Resources Agency, U.S. Corps of Engineers, and Tennessee Valley Authority working together.

Time is the friend of the carp and the enemy of the reservoirs.

If we don’t begin immediately to prevent the migration upstream, Silver Carp will destroy the ecology, fishery, recreation, and economic engines of Guntersville, Nickajack, Chickamauga, Watts Bar, Melton Hill and Ft. Loudoun and Tellico lakes/reservoirs and their tributaries.

This is fact, not speculation.

To learn more about the impacts of invasive aquatic species, visit the Watts Bar Ecology and Fishery Council website at

The Council is working tirelessly to protect the Tennessee River Ecosystems.

You can help by visiting the website, click on “Contact” and become a stakeholder in the protection of our beautiful lakes by filling out the form.

Membership is free, you will receive only a few emails during the year to provide updated information on the migration of the Silver Carp and let you know when meetings and presentations are scheduled. Only with a very large number of stakeholders can the Watts Bar Ecology and Fishery Council influence local, State, and Federal legislatures to take action.

If nothing is done, we will lose the most important aquatic natural resource and economic engine this region has to offer – please don’t let this happen. The WBEFC offers a 40-minute educational ecological presentation on the impacts of invasive aquatic species to groups of over 25.

If your organization would like to view this presentation, contact me at