Toledo Bend
Bi-State
Alliance

THE ATTACHED MATERIAL IS INFORMATION ON HYDRILLA AND HYDRILLA CONTROL WHICH I HAVE ACCUMULATED OVER A PERIOD OF SEVERAL YEARS AND WHICH SHOULD BE USED AS A BASE FOR FURTHER STUDY ON THE CONTROL OF THIS WEED.

WILLIAM B. LEWIS

719 OAK BLUFF DRIVE

MANY, .LA. 71449

SEPT. '97

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RECOMMENDATIONS FOR AN AQUATIC PLANT CONTROL PROGRAM ON TOLEDO BEND

It is recommended that the SRA's and Wildlife and Fisheries Departments of Texas and Louisiana in cooperation with Lake Users and Lake Residents produce an Aquatic Plant Management Plan For Toledo Bend Lake.

It is further recommended:

* that this Plan be developed and implemented in such a way that plant management and control is consistent with supporting all recreational, industrial, agricultural, and municipal uses of the water of the Lake.

* that the development and implementation of the the Plan be a cooperative effort of the responsible Governmental Organizations and the effected private citizens and public business organizations.

* that the Plan be custom made for Toledo Bend and reflect the combination of Ecological Needs and Lake Users Interests unique to this Lake, while remaining within the constraints imposed by law and any existing Sabine River environmental impact statements or agreements.

* that the development of Plan provide for the continuing information and education of the public.

* that the main thrust of the Plan to be to control of aquatic plants and the enhancement of fish habitat. This will involve :

a. Controlling aquatic plants where they interfere with access to the Lake and where the plants are interfering with specialized recreational activities such as skiing and swimming.

b. Conserving existing aquatic plants or promoting the growth of additional plants that are desirable for ecological or recreational purposes.*

* that the Plan include the geographical zoning of certain areas where special interests of the Lake Users be given priority of plant control. Such areas include skiing, water discharge for municipal use, drafting of water for fire protection, etc.

* that the Plan provide for short term or immediate solutions to problems that have reached a serious level of damage or curtailment of recreation, water access, fire protection, fish spawning, use of docks and boat launching. Solutions may involve clearing lanes or small areas using chemicals or mechanical harvesting.

.

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PROGRAM FIRST STEPS

In preparation for implementing any large scale control program it will be necessary to determine the following:

* +The nature and extent of aquatic infestation--the location and area involved.

* The type of plants involved

- Hydrilla

- Watermilfoil

- Coon tail

- Water hyacinth

- Others

* The rate of growth of the biomass.

* The method of making these determinations,ie; overflights with photographs and land surveys to verify and correlate the photographic data

* The type of control mechanism indicated

- Chemical

- Mechanical

- Biological

- Water Level fluctuation

- None

* The changes in the State (Texas and Louisiana) and Federal laws necessary to legalize the implementation of the program.

The Plan must provide both short term and long term solutions to the problems to best serve the interests of all recreational enthusiasts. This may involve the use of several types of control implemented in phases; mechanical means to clear lanes,use of chemicals to clear small areas, and the use of biological agents for long term control.

THE NEED FOR A PLAN IS URGENT

IT IS NOT FAIR TO THE PEOPLE LIVING ON THE LAKE TO HAVE TO GIVE UP THEIR HOMES AND RETIREMENT BECAUSE OF A LACK OF EFFORT ON THE PART OF THE LAKE ADMINISTRATION.

IMMEDIATE ACTION IS REQUIRED BECAUSE THE LONGER THE PROBLEM EXISTS THE FEASIBILITY OF USING VARIOUS CONTROLS BECOMES MORE QUESTIONABLE AND THE COST OF ANY CONTROL INCREASES.

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THE IMPACTS ASSOCIATED WITH EXOTIC AQUATIC PLANTS

Exotic aquatic plants such as Hydrilla have proven to provide an enhancement to fish habitat and food supply. Such plants have replaced the trees and brush that were once present when the lake was young and have been a reason the fishing in the lake has remained at a high productive level. By providing a food supply of forage fish, invertebrates, and plant- and zoo-plankton, and a habitat for young fish, these plants have become an important part of the limnology of Toledo Bend.

There is a down side however to the presence of these plants.

The plant (Hydrilla Verticillata), or just hydrilla, is known to be a plant which without control will take over a lake. That is what is happening on Toledo Bend today. The problem is so bad in some areas that urgent need exists for some form of control to prevent further uncontrolled expansion and a need for some means of dealing with the already existing mass of weeds. Without control of the weeds Toledo Bend will lose its attraction as a recreational lake.

Problems currently existing include the following:

* The weed growth is so dense in the shallow coves (which include the areas where most retirees either live or will be buying homes) that once favorite swimming areas and skiing areas are no longer usable.

* Boats can access the open water only by continually cutting a trail through the moss.

* Fire protection has been jeopardized because Fire Fighter's can no longer draft water from the lake without ingesting grass into their pumps.

* Some of the best spawning areas are no longer accessible to the fish when the water is kept at "Guide Rule" levels.

The future situation is more grim. It is really frightening to know that we are seeing only the beginning of the problem. Within the next few years all water of depth less than 25 to 30 feet will be taken over by the Hydrilla. This has been demonstrated time and time again in all sorts of bodies of water throughout the country.

We are not alone in this situation. Over the United States hundreds of millions of dollars are being spent each year in research to find a solution to the control of Hydrilla. As far as I can determine there is no State that is not involved to some degree in an effort to control the spread of this plant which has succeeded in displacing the kinds of plants we used to see in our lakes

What is this plant? Where did it come from? How did it get to be so wide spread and so damaging in so few years? Why have we found it so hard to find a way to manage it? What have researchers learned about the control of this plant with all the money that has been spent? Is there any solution to the Management of Hydrilla and if so when will it be available?

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I will attempt to answer these question by passing along to you what I have been able to find out by contacting some of the people and Research Organizations that have been doing the research.

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HYDRILLA (Hydrilla Verticillata)

Definition: A Submersed, Caulescent Vascular Hydrophyte- a Macrophyte

Hydrilla Facts:

* Has few known enemies, can live out of water for days, sprout from a single stem of stem fragment.

* If left unchecked it can take over a lake--restricting all recreational activities and access to open water.

* Came to Florida (from Africa) as an aquarium decoration in the 1950's.

* Spread and began to be a serious problem after the boating boom of the 1960's.

* Exists in all Southern States and as for north as Washington, D.C.

* Is menacing waterways and lakes throughout the United States.

* Florida like several states has spent hundreds of million of dollars to control Hydrilla.

* In So. Carolina the weed clogged water intakes of a hydro-electric power plant and shut down the facility for several weeks.

* Forced the Tennessee River Authority to close its Hydro-electric plane in Guntersville, Ala. for weeks in 1989.

* Alabama has a state-wide program to try to keep Hydrilla under control along the Tombigbee River and the Mobile Delta. "Without control in a few years you could walk across the waterway" says Doug Blount of the U.S. Army, Corps of Engineers

* It is a hitchhiker, travelling from one water body to another on boats and trailers.

* Once rooted, Hydrilla can reach a biomass density of 20 to 130 tons per acre.

* The water can become so choked with the grass that the growth of micro-scopic algae that produces oxygen is inhibited.

* Fish and other aquatic creatures find it hard to get around and their growth is stunted.

* Will grow in water 12 meters(35 ft.) deep.

* Found in drainage and irrigation canals, ponds and lakes and in flowing or tidal streams.

The U.S. Department of Agriculture and the U.S. Army Corps of Engineers in their collaborative projects have put the biological control of Hydrilla at the top of their list.

Worldwide faunal inventories resulted in selection of candidates of biological control agents from tropical and sub-tropical regions.

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EFFORTS TO CONTROL HYDRILLA

All States and the Federal Government are involved in programs of research directed at finding an answer to the problem of controlling Hydrilla. Nations in Europe, Asia, South America, and Africa are using various programs to try to keep the weed in check.

In this country the U.S. Government and the States are spending hundreds of millions of dollars in research in a, so far, futile effort to find a "good" solution or just to find a way to live with it.

So far in all this research only one viable agent has been found to economically control the weed. That agent is the White Amur Carp or Grass Carp. The White Amur Carp is one of three Chinese Carp that have been used in this country for food. The other two are the Silver and the Big Head Carp.

The various means of control of Hydrilla (as well as other hydrophytes) include:

* Mechanical Means

* Herbicidal Chemicals

* Biological Agents

* Pathological Agents

* Draw-down (Water Level Fluctuations)

MECHANICAL MEANS

The use of Harvesting Barges have been tried in a number of experimental efforts. This method has proven to be costly and only moderately successful in clearing lanes and small areas .

Its disadvantages are;

* It is costly because of the heavy equipment involved and the slow rate of removal of the grass.

* It spreads the grass because the fragments of grass produced will simply drift and start new growths.

* Its effectiveness is minimized by the fact that Hydrilla is approximately 90% water.

New methods are currently being tried on some of the T.V.A. lakes in which a machine harvests and mulches the Hydrilla. (Lake Chickamauga and Lake Nickajack). The Machine is now being constructed and results of it effectiveness will be determined during a 3 year trial ('94,'95.'96). This method is being tried because the use of Chemical Herbicides which had been used was terminated after an outcry by the fishermen and environmentalist.

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CHEMICAL HERBICIDES

Several chemical herbicides have been tried and are being used to control various aquatic plants. Used individually and in combination these have had relatively good success.

Although fairly successful when used to control some hydrophytes, they have remained largely unsuccessful in controlling Hydrilla.

Drawbacks to the use of herbicides include:

* Effect is not long lasting, often requiring several treatments a year.

* The cost is generally prohibitive, running from $200.00 to $600.00 per year per acre.

* Some are toxic to marine life, animals and humans.

* Cannot be used if the water is to be used for irrigation.

* Difficult to apply and to establish threshold quantities.

* High cost of chemicals and application equipment

Some of the chemicals used as aquatic plant herbicides are:

Pellets:

Endothal (Hydout)

Cutrine

Sonar

Liquid

Copper Sulfate

Cutrine/Diquat

Rodio

Of these Sonar seems to be the only one effective against Hydrilla

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BIOLOGICAL CONTROL

A long-time worldwide search to find some animal, fish or insect to control Hydrilla has been relatively unsuccessful. Searches have been conducted all over the world and although some biological forms have been found, their introduction into this country has not been successful except for laboratory tests and limited field experimental programs.

Since Hydrilla originated in Africa and first migrated to Asia and then into Europe the search for a control has been located in these areas of the world.

GRASS CARP

Most notable of these biological agents has been the White Amur or Grass Carp. The White Amur is one of the family of Chinese carp

(Silver, Big Head,White Amur) raised in this country for food and sold principly to Asiatic immigrants.

Grass Carp have been shown to be an effective voracious herbivorous fish, capable of eliminating all submerged aquatic plants from lakes for several years.

Concerns about introducing grass carp have been largely removed by the development of a functionally sterile form of grass carp (triploid grass carp). Still some significant questions remain about the ability to manage aquatic weeds with grass carp in large open systems.

These concerns involve questions about;

A. Reproduction

B Dispersion

C. Introduction of Diseases and Parasites

D. Alteration of the Aquatic Habitat

E. Vulnerability of Biological Communities

A. Reproduction

Numerous experimental studies in the laboratory and in controlled stocking have shown that Triploid Carp cannot reproduce.

The three sets of chromosomes in the Triploid Carp results in the production of non-viable gametes in both the male and female.

Diploid Carp(two sets of chromosomes) can reproduce viable eggs but the probability of these eggs hatching is infinitesimally small because of the incubation requirements. The eggs are heavier than water and must not be allowed to settle to the bottom. The eggs must be suspended by a vertical flow of greater than 2 miles per hour. The incubation period ranges from 16 to 60 hours depending on the temperature.The incubation period will remain from 23 to 33 hours if the temperature remains between 70 and 78 degrees. These requirements mean that the eggs must be hatched in a swift running stream and have at least thirty miles of turbulent stream travel.

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B. Dispersion and mobility

Many studies have been conducted to determine the movement of carp after they are introduced and the general finding are:

1. After the first few hours after release or after a period of getting acclimated the carp move only short distances from the release point. Less than a few miles.

2. They tend to stay where the food is.

3. Movement does not differ much between daylight and night.

4. The carp will travel as much as 1.5 miles in hot weather and 1/4 mile in cold weather , but do not leave their general feeding area.

C. Introduction of Disease and Parasites

The only known parasite introduced into the United States by the importation of Grass Carp is a Cestode (Bothriocephalus).

This parasite has caused no adverse effects in fish found in natural waters in the U.S.A.

The source of Triploid Carp in this country is Stuttgard, Arkansas and these Carp should be free of disease and parasites.

D. Alteration of the Aquatic Habitat

The Grass Carp have the potential to completely remove aquatic plants from a lake, if the number of Carp released into the lake are not balanced against the amount of grass you desire to be removed.

If Carp are to be used to control and not eliminate the Hydrilla, then the release rate must be regulated so that the rate of grass consumption by the Carp is equal or be less than the expansion rate of the grass. The Grass Carp have a preference for Hydrilla but will eat any kind of aquatic plant.

A model for the release of Grass Carp is currently being developed by the U.S. Army Corps of Engineers in conjunction with the TVA. There are three locations in Louisiana that are being used as data sources in the determination of this model. These lakes are in the Monroe, La. area.

The results of Carp stocking in Lake Guntersville (1983 to 1989)

showed the following effects on the resident fish community.

* No adverse effects on the total fish community

* A shift in the forage base from sunfish to shad

* An increase in the growth rate of largemouth bass

* An increase in the total fish standing stock.

(all results attributed to the significant decline in the amount of submerged aquatic vegetation)

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E. Vulnerability of Biological Communities

Grass Carp are strictly herbivorous and pose no threat to the Biological Community. Samples of the Carps stomach contents taken during during many studies have verified this.

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INSECTS

The information on Insects comes from the Proceedings of the 28th Annual Meeting of the Aquatic Plant Control Program in Baltimore Md. 15-18th Nov. '93.

After years of trying to use herbicides for the control of Hydrilla and finding the cost and lack of effective control unsatisfactory, the U.S. Department of Agriculture and the U.S. Army Corp of Engineers began a collaborative effort to find a biological agent for control.

A worldwide search for a faunal agent was begun in the early 1980's and is continuing today.

As a result of these searches several specimens of flies, weevils and moths have been found and tested in this country.

Although some promise of the effectiveness of these specimens to control the growth of Hydrilla has been demonstrated in the laboratory and in restricted field tests, the widespread use of the insects has not been proven to be a successful solution. Studies are continuing but several drawbacks have been identified.

Some of the problems identified include:

* the uncontrolled reproduction of the insects once established. They could completely eliminate Hydrilla and in some cases this is not the desirable end.

* The insects could become a nuisance similar to the knats we have now on Toledo Bend.

In spite of these short comings several species of the insects have been, and are being, released in several parts of the United States. Several small lakes in Florida were selected for release of two species of a leaf-mining fly (Hydrilla Pakistanae in1987) and (Hydrilla Balciunasi in 1989). An additional 4 million H. Pakistanae were released in 1989 in the southeastern United States.

The first two insects tested were from India, a tuber feeding weevil (Bagus Affinis) and a leaf mining fly (Hydrilla Pakistanae).

The B. Affinis required a long dry spell of draw down and was discarded as a potential control.

The H. Pakistanae did establish in Florida in 1987.

Six Australian species were recognized and two--a leaf mining fly (Hydrilla Balciunasi) and a stem boring weevil (Bagus Hydrilla) proved successful and were released in Florida in 1989 and 1991.

Several species of moths were studied but were dropped for various reasons. Most were not Hydrilla specific.

Additional search is continuing in China.

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Releases include: (1993 Data)

* H. Pakistanae in Fla., Ga.,Ala.,La., and Tex. in 1987.

(935,800)

* H. Balciunasi in Fla. and Tex. in 1989. (208,045)

* Subsequent releases over 4 million H. Pakistanae and over 200 thousand H. Balciunasi.

There are three rearing facilities at Federal Agencies.

* U.S. Dept of Agriculture, Agricultural Research and Education Service, Aquatic Plant Management Laboratory, Ft. Lauderdale, Fla.

* U. S. Army Corps of Engineers, Waterways Experiment Station, Vicksburg, Ms.

* Pond Facilities, T. V. A. Reservation, Muscles Shoals, Ala.

PATHOGENS

Studies of pathogens as a Hydrilla control has been focused exclusively on the use of Endemic Fungal Organisms.

Two most promising have been strains of Fungus Mycolestodiscus Terrestris Ostazeski (M T) isolated from Hydrilla in Texas. The fungus was identified in Lake Houston and Lake Sheldon.

Small scale testing in tubes and pools showed some promise,but the ability to formulate a means of applying the fungus, determining the threshold amounts, and assuring what types of plants the fungus will attack must be found before large scale testing can proceed.

In 1980's the fungus (M T) in a mycelial mass was incorporated into a Calcium Alginate medium to form pellets which were tested with mixed success.

MT testing has been performed in 1980 and 1981 at Stockbridge Ma.

In 1980 tests using MT in a mycetial mass incorporated into a calcium alginate medium were performed on Eurasian Watermilfoil by EcoScience and US Army Engineers Waterways Experiment Station.

In July, 1990 tests were performed in small ponds at the Lewisville Aquatic Ecosystem Research Facility. The results were not encouraging

DRAWDOWN

On Toledo Bend drawdown would not be successful because of the very limited range of water levels. The difference between max pool level of 172'msl and minimum power pool of 162'msl only gives a variation of ten feet. To dry up the hydrilla a change of 20 feet would be required and this would not be tolerable.

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THE 1989 EXECUTIVE SUMMARY OF THE GRASS CARP STOCKING IN LAKE GUNTERSVILLE

In 1983 the TVA started a program of Carp release in Lake Guntersville, Ala. The lake had an infestation of both Eurasian Watermilfoil and Hydrilla.

in 1987 there was a 68% reduction in the Watermilfoil and the Hydrilla had been effectively removed. This was attributed to 3 years by the Grass Carp.

In 1988 (the fourth year of stocking) the Watermilfoil had increased 2-fold, indicating repetitive stocking would be required to achieve desirable results.

Surveys conducted to assess the effects of the White Amur Carp on the resident fish community showed:

1. No adverse effects on total fish community

2. A shift in the forage base from sunfish to shad

3.An increase in the growth rate largemouth bass

4. An increase in the total fish standing stock (number of fish)

All results attributed to the significant decline in the amount of submerged aquatic vegetation.

"Chemical treatment with EPA-labeled herbicides and reservoir drawdown have been mainstays of TVA aquatic plant management program. In spite of large-scale herbicide application and special water level manipulations, the aquatic macrophytes have continued to expand.

Although several biological control agents are under evaluation for Eurasion Watermilfoil and Hydrilla, the Grass Carp or White Amur is the only organism available that offers potential long term control of aquatic weeds in large reservoirs."

In the TVA study mono-sex (female) carp were used in an area that could be sealed off from the main lake. Upper Town Creek off Lake Guntersville contained about 396 acres which could be isolated from the main lake using a barrier screen across two concrete culverts. The stocking rate was 11.5 carp per acre which was intended to control and not remove completely.

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THE FOLLOWING NOTES ARE INDICATIVE OF THE RESULT OF DOING NOTHING TO CONTROL HYDRILLA

* April 29, '96 JOE MACALUSO, OUTDOOR WRITER FOR ADVOCATE

* LAKE PENCHANT AND LA,E BOEUF ARE VIRTUALLY UNFISHABLE

* LAKE THERIOT IS FACING A SIMILAR PREDICAMENT

* SPANISH LAKE SOUTH OF BATON ROUGE WAS A MIRE LAST SUMMER

* THE 21 INCH CANAL AND SEVERAL WATERWAYS OF THE "MAJOR HIGHWAY" IN THE ATCHAFALAYA BASIN HAVE BEEN REDUCED TO ONE-LANE PATHS

* CHICOT LAKE, A RESERVOIR IN THE STATE'S QUALITY LAKES PROGRAM IS FACING A SIMILAR FATE.

* MILLER'S LAKE IS ON THE LIST

* THE EVEN MORE POPULAR ASSUMPTION PARISH KLAKES--VERRET AND GRASSY-- ARE SHOWING SIGNS OF INFESTATION

* FALSE RIVER HAS IT

* AND SEVERAL CANALS NEAR COCODRIE ARE ITS NEW HOME

THE BIGGEST AQUATIC PLANT PROBLEM IN FLORIDA, TEXAS, LOUISIANA, AND GEORGIA _

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A FEW BRIEF DESCRIPTIONS OF VARIOUS STATE'S EFFORTS TO CONTROL AQUATIC PLANTS WITH GRASS CARP AND SOME CONCERNS EXPRESSED

If there is any one thing certain in the situation on Grass Carp use as a plant management tool it is the controversy of user opinions. CONFLICT is the name of the game. For all the studies that indicate the advisability of controlling hydrilla there is still a number of people that are adamant that hydrilla is Good and that's it.

In spite of all the demonstrated loss of valuable water recreation and damage to fish habitat and lake access, there are still those that don't understand or just don't believe that the plant is dangerous unless it is controlled.

FLORIDA 1974 TO 1994 LAKES ORANGE AND LOCHLOOSA

ALABAMA 1983 TO 1988 LAKE GUNTERSVILLE

LOUISIANA 1974 TO 1994 POLICIES, CONCERNS, AND ISSUES

TEXAS 1994 GRASS CARP PROGRAM

SO. CAROLINA 1992 to 1904 CARP USE ON THE SANTEE-COOPER SYSTEM

SO. CAROLINA 1994 CARP POLICY

VIRGINIA 1979 TO 1994 GRASS CARP PROGRAM

TEXAS 1981 TO 1994 LAKE CONROE GRASS REMOVAL PROGRAM

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NOTES FROM THE OPENING ADDRESS BY J. BEN ROWE, COMMISSIONER, FLORIDA GAME AND FISH COMMISSION AT THE GRASS CARP SYMPOSIUM IN GAINSVILLE FLORIDA IN MARCH 1994

"WHY WE ARE HERE IS SIMPLY THIS."

"Florida is experiencing serious infestation of submersed weed principally hydrilla, and this plant is now present in every watershed in the State. Approximately $6 million/per year of public funds are spent annually for chemical, mechanical, and biological control of hydrilla, primarily to maintain fisheries and wildlife habitat, access for boaters, and flood control purposes. The grass carp has been in the State since 1970, and years of research and experience has been attained by scientist and fisheries biologist."

"Locally, Orange and Lochloosa provide 20,000 acres of prime sportfishing, and associated wetlands are used by bald eagles, osprey, otters, snakes, gators, and many other types of critters. A drought , producing low-water levels and extensive hydrilla growth has reduced lake use to nearly zero the past two years. In good condition , these lakes produce an economic benefit of over $10 million /year. These lakes have contained various amounts of hydrilla for over 20 years: but in the past two years over $1 million worth of herbicides have been used in the lakes."

"It doesn't take a rocket scientist to figure out that $1 million will purchase many grass carp, and we know that they can provide weed control for 10 to 20 years.-------

------We have been told that grass carp is the greatest thing since sliced bread. We have also been told that the grass carp can be an ecological disaster. ---------------I believe it has been an unwritten policy of the Game and Fish Commission to not stock important fish and wildlife lakes until we are reasonably assured that environmental degradation will not occur. THE PUBLIC HOWEVER, FIGURES THAT AFTER 25 YEARS OF RESEARCH, HOW MUCH LONGER WILL IT TAKE US TO LEARN HOW TO USE THIS FISH? After all, if we can place people on the moon, how difficult can weed control be?"

This is not a complete transcript of Mr. Rowe's address, but it contains enough to get the idea --that sometime we have to start a more aggressive program of grass control.

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THE 1989 EXECUTIVE SUMMARY OF THE GRASS CRP STOCKING IN LAKE GUNTERSVILLE

In 1983 the TVA started a program of Carp release in Lake Guntersville, Ala. The lake had an infestation of both Eurasian Watermilfoil and Hydrilla.

In the TVA study mono-sex (female) carp were used in an area that could be sealed off from the main lake. Upper Town Creek off Lake Guntersville contained about 396 acres which could be isolated from the main lake using a barrier screen across two concrete culverts. The stocking rate was 11.5 carp per acre which was intended to control and not remove completely.

In 1987 there was a 68% reduction in the Watermilfoil and the Hydrilla had been effectively removed. This was attributed to 3 years of stocking by the Grass Carp.

In 1988 (the fourth year of stocking) the Watermilfoil had increased 2-fold, indicating repetitive stocking would be required to achieve desirable results.

Surveys conducted to assess the effects of the White Amur Carp on the resident fish community showed:

1. No adverse effects on total fish community

2. A shift in the forage base from sunfish to shad

3.An increase in the growth rate largemouth bass

4. An increase in the total fish standing stock (number of fish)

All results attributed to the significant decline in the amount of submerged aquatic vegetation.

"Chemical treatment with EPA-labeled herbicides and reservoir drawdown have been mainstays of TVA aquatic plant management program. In spite of large-scale herbicide application and special water level manipulations, the aquatic macrophytes had continued to expand.

Although several biological control agents are under evaluation for Eurasion Watermilfoil and Hydrilla, the Grass Carp or White Amur is the only organism available that offers potential long term control of aquatic weeds in large reservoirs."

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GRASS CARP POLICIES, CONCERNS, AND ISSUES IN LOUISIANA

(These notes taken from a paper presented at the Grass Carp Symposium in Gainsville, Fla. Mar. 7-9, 1994 by Louie Richardson, Aquatic Plant Research and Control, La. Dept. W & F)

1971--The Louisiana Department of Wildlife and Fisheries (Dept. of W& F) banned the importation, transportation and sale of Diploid Grass Carp. This was based on the potential to reproduce in the State's 350 million acres of marshlands and inland fresh water areas.

1974--Four closed systems ranging from 30 to 250 acres were stocked with either 15 or 30 Grass Carp per acre.

Results indicated the following:

a. Carp effectively controlled coontail and Eurasian Watermilfoil in the study lakes.

b. Stocking rates should be correlated to the biomass of the target species.

c. An increase in game fish noted during the 5-year study period in one study area.

d. Excessive stocking may have adverse effects on some native fish.

e. Adequate control of dense aquatic vegetation was obtained in 2 to 3 years by stocking 15 6-inch carp per acre.

f. 6-inch carp attained a weight of 15 lbs. in 14 months.

g. Carp were readily captured using Trammel and/or Gill nets.

h. Use of Grass Carp for weed control can be useful under certain conditions.

i. Diploid Carp should not be released where they could escape into the rivers system.

j. Development of Sterile Grass Carp could enhance the use of Carp for biological weed control.

The Dept P & W approved a research proposal for the large-scale maintenance operational tests in public waters by Inland Fisheries Division personnel. The research goal was to refine stocking rates of Triploid Grass Carp to achieve control, but not elimination of aquatic vegetation. Stocking rates were correlated to total acres infested, species composition and biomass of each species.

1975--Reproduction was documented in many of the States major rivers. Twenty-three percent of the larvae sampled in the Red River were Grass Carp. However recruitment of the larvae to fingerlings were severely restricted by hydrologic and biologic events.

PAGE 20

1988--Responding to a Legislative Directive, the Dept. of W& F organized a CARP TASK FORCE to review all available information of the three Chinese Carp (Silver, Bighead and White Amur).

This Task Force reported back to the Legislature recommending banning the import, transport and possession of Silver, Bighead and Diploid Grass Carp. They recommended approval of the use of Triploid Grass Carp to control vegetation in catfish culture ponds under a permitting system.

1992--Hurricane Andrew created an almost total fish kill in the Atchafalaya Basin and 200 million fish died. The Red, Ouachita and 30% of the Mississippi Rivers flow into this basin. All three of these rivers have producing Grass Carp, but no Grass Carp were noted in the massive fish kill.

1993--Permitting of Triploid Carp began for vegetation control in private and municipal waters.

"A major concern is over stocking. However another major concern is invasive exotic plants dominating our water system and causing a loss of native plant biodiversity and the organisms dependent on that diversity."

"Overstocking is reversible over time, whereas establishment of a monospecific population of exotic plants can result in severe restriction or loss of man's intended use of the resource and disrupt the ecological balance of our waterways.

PAGE 21

GRASS CARP PROGRAM IN TEXAS

Philip Durocher, Dir. of Inland Fisheries Texas Parks and Wildlife

1992--Tex P & W approved the use of certified Triploid Grass Carp for vegetation control in Texas waters.

Prior to that time all Grass Carp were prohibited.

Rules require:

Permit to possess

Set the criteria for permit approval

Allow only licensed Texas fish farmers who hold Exotic Species Permits to sell certified Triploids

Diploids still prohibited in the State

Based on:

Overabundance of vegetation in small ponds

Weeds have reached levels to prevent use of some private waters by recreational fishermen

To a lesser degree , some public waters are being negatively affected.

Under previous law only herbicides or illegal Diploids were available to control the weeds--both unacceptable for good management of public waters.

Concern that herbicides and Diploids would find their way into public waters

Permitting Triploids gave private pond owners an economic reason to stop importing Diploids

Rules did several things:

Legalized Triploids by permit

Set a $15 fee for permit plus $2 per fish

Requirements and criteria were established

Emphasized illegality of Diploids

Triploids must come from out of State and be certified by either P & W or the shipping State.

Only licensed Texas fish farmers were allowed to sell the carp, becoming the middle man in the transaction.

Using a conservative approach, only 7 fish per vegetated acre are permitted

Since 1992 nearly 2900 permits have been issued and 78,000 fish have been stocked. Much less than had been expected.

Public waters were handled in a separate issue.

The Department may allow stocking in public waters under another permit system.

The same criteria for permit approval is used

PAGE 22

CARP USE ON SANTEE-COOPER SYSTEM

LAKE MARION/LAKE MOULTRIE

This lake system consists of 170,000 acres of prime fishing and hunting water.

This most economically important lake system in the Southeast had not had problems with submersed aquatic plant populations prior to the early 80's. This all changed with the introduction of hydrilla. The plant was first noticed in 1982 and despite extensive use of herbicides it spread and quickly replaced more desirable elodea as the predominant submersed species.

In 1985 hydrilla was limiting access to about 11,856 acres of the upper end of lake Marion. Because of the dense mass fishermen and hunters were deprived of the use of that end of the lake which had at one time been a favorite recreational area on the lake.

Extensive use of herbicides proved expensive and had short term effectiveness and mechanical removal was time consuming, costly and worked on limited space and for limited time. By 1987 (5 years) it had spread into areas where vegetation had never existed and was impacting a growing number of water uses and threatened to infest up to one-half of the lake system.

A long term solution was needed. Based on the effective use of carp in Florida lakes during the 70's it was decided to stock carp in the upper end of Lake Marion. A multiagency board that coordinates plant management came up with the plan to stock 300,000 carp over a 3-year period with a final rate of 25 carp per vegetated acre.

In 1989,1990 and 1991 300,000 triploid carp were stocked by So. Carolina Aquatic Plant Management Council of the So. Carolina Water Resources Commission The carp were released at a rate of 100,000 per year. After the initial three years and additional 100,000 were released in1992 to compensate for losses during hurricane Hugo and a spring fish kill.

Studies to monitor aquatic plant coverage, native fish population, carp movement and water quality were conducted by U.S. Army Corps of Engineers, Waterways Experiment Station. After two years hydrilla continued to increase. In the 3rd year (1991) a slight decline of 20% was noticed. In the 4th year significant decline (58%) opened up areas of the lake that had been inaccessible to the public for many years. In 1993 the hydrilla had been reduced by another 10%.

THE CONSEQUENCES:

Upper Lake Marion which was once a popular fishing area is once again being heavily utilized by the public. Hydrilla was not eliminated but was substantially reduced, with a resulting increase in the diversity of the plant community.

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Hydrilla continues to increase in other areas of this large lake system. Grass carp were successful in controlling 9,000 acres of the hydrilla but hydrilla continues to impact an additional 17,000 acres in the lower end of Lake Marion.

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SOUTH CAROLINA CARP POLICY

Diploid Carp are illegal in So. Carolina; however Triploids have been legal for use since 1985. The So. Carolina Wildlife and Marine Resources Department regulates the importation of grass carp by a permit system. Permits are issued only to reputable out-of-state suppliers. Coulter Counter Method of checking ploidy is used on 5% or 120 fish of each shipment.

Production of sterile grass carp is just beginning in So. Carolina and one production facility is under development. Special precautions are taken to assure that the diploids (brood stock) do not escape to public waters. In State holding facilities (dealers) should also use escapement barriers, but purchasers are not required to have them.

CONCERNS

There are no overriding issues or concerns in S. C. that currently limit the use of grass carp in most waters. However, important considerations for stocking large impoundments in the State include the following:

a. Determining stocking rates that control target species, and minimizing impacts to nontarget aquatic plants.

b. Determining the potential for impact from movement of the carp to downstream waters.

c. Assessing the impact to operations at waterfowl management areas located next to target waters.

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GRASS CARP PROGRAM IN VIRGINIA

Started biological control of exotic plants in 1979 with female hybrids with import of 1600 from J. M. Malone in Arkansas. Cross of female Bighead and a (sex-changed) male Grass Carp.

Prior to 1979 unknown numbers of grass carp had been imported by private pond owners.

In 1979 hydrilla was misidentified as Elodea and planted in the Potomac River. Hydrilla has been widespread in Virginia since then.

In 1984 Triploids were approved for use (from J. M. Malone and Leon Hill in Arkansas) and a stocking rate of 16carp/vegetated acre was approved.

In 1989 Fish and Game formed a Grass Carp Committee who:

a. produced an informative brochure about weed control and use of grass carp

b. Revised stocking rates to two rates:

Control Eradicate

Intermediate preference plants 16/Ac. 32/Ac.

Preferred Plants (hydrilla) 8/Ac. 16/Ac.

c. Began Ploidy Testing---Three Universities do the testing

Currently issuing about 550 Permits/yr. for 9,000 triploids

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THE LAKE CONROE HYDRILLA REMOVAL PROGRAM

In 1981 Texas A & M University under contract to the State imbarked on a plant removal program on Lake Conroe. This one program has given the opponents of the use of Grass Carp for aquatic plant control the weapon they use to defeat any move to use the fish for controlling hydrilla in every State in the country.

Some facts often ignored in the assessment of the success of the program include:

The program was designed to remove all the grass and not to control

the weeds.

Diploid Carp were used . Triploids were not available.

A tremendous overstocking was used (30 carp/vegetated acre)

The lake was a public water source for Houston and Hydrilla is noted for fouling the taste and smell of water.

Many Developers were making tremendous fortunes on the sale of land and the developing of expensive housing projects and the hydrilla was impacting the attractiveness of the lake as a recreational lake for sailing , skiing , swimming etc.

Fishing, although excellent, was not the primary source of revenue or major form of recreation for people buying property on the lake.

The average depth of the lake was only 20 feet. Most of the good fishing coves were much less than that and were the first to feel the impact of the grass.

Although the grass-lines were beginning to be productive, the woods and creeks still provided the most productive structure fishing.

Locating fish and brush piles with a depth finder was possible before the grass became to bad.

SITUATION TODAY

( Webb, Henson, Reed--Tex. Parks and Wildlife, Inland Fisheries)

The macrophtytes are still virtually all gone.

Effects of the macrophyte removal remains controversial.

Whether fishing is better or worse than at the peak of macrophyte coverage is a matter of opinion.

The Lake is a high profile fishery near a major metropolitan area and is managed using every available tool.

Conroe fisheries are still in a state of flux as productivity changes , species expand and decline, shoreline is altered by development, and fish management activities such as length limits and stockings take effect.

The population status reflects all of these factors and cannot be evaluated simply in terms of the effect of macrophyte loss.

Even though 170,000 natural (diploid) carp were used in that program there has been little evidence that the fish have been established below or above Lake Conroe in the San Jacinto River. It may be years before we know if they will ever be.