PUBLICATION DATE:  25/06/2008

RATING

AUTHOR:  Dr. Martin W. Brunson, Extension Leader/Fisheries Specialist - Mississippi State University Extension Service Information Sheet

Carp, or white amur, have been used for aquatic vegetation control in Mississippi for the past two decades. These fish, used as a "biological control" for aquatic vegetation, can be effective and cost efficient when stocked at appropriate rates and when the problem-weed species is a plant preferred by carp. Although these fish are voracious herbivores, they exhibit preferences for the softer, low-fiber, high-moisture plants when given a choice. Even when there is no alternative, grass carp will not always provide adequate control of certain plants that they do not prefer to eat.

It is important to identify the problem plant(s) properly and to choose to stock grass carp only when the problem plants are those that grass carp are proven to control. A number of studies have determined grass carp preferences of the various common aquatic plants, and results from some of that work are summarized in this publication. In some cases, although grass carp are listed in the scientific literature as preferring a certain weed, field experience in Mississippi shows them to be ineffective on a consistent basis. Those plants that grass carp do not consistently control are rated as "low" in effectiveness (Table 1).

Common Name	Scientific name	Preference	Effectiveness
Coontail	Ceratophyllum sp.	High	High
Bushy pondweed, Naiad	Najas sp.	High	High
Arrowheads	Sagittaria sp.	Moderate	Low
Willows	Salix sp.	Low	Low
Spikerush	Eleocharis sp.	Low	Low
Hairgrass, Slender spikerush	Eleocharis acicularis	Moderate	High
Cattail	Typha sp.	Low	Low
Pondweed	Potamogeton sp.	Moderate	Moderate
Bladderwort	Utricularia sp.	High	High
Fanwort	Cambomba caroliniana	High	High
Parrotfeather	Myriophyllum aquaticum	Moderate	Moderate
Water primerose	Jussiea sp.	Low	Low
Smartweed	Polygonum sp.	Low	Low
Filamentous algae	Spirogyra sp., many others	Moderate	Low
Muskgrass (algae)	Chara sp.	High	High
Stonewort (algae)	Nitella sp.	High	High
Planktonic algae	Many species	Low	Low
Alligatorweed	Alternanthera philoxeroides	Low	Low
Hydrilla	Hydrilla verticellata	High	High
Water hyacinth	Eichornia crassipes	Low	Low
Duckweed	Lemna sp., Spirodella sp.	High	Low
White waterlily	Nymphaea odorata	Low	Low
American lotus	Nelumbo lutea	Low	Low
Burreed	Sparganium sp.	Low	Low
Bulrush	Scirpus sp.	Low	Low
Elodea	Egeria densa	High	High
Water fern	Azolla caroliniana	Moderate	Low
Water cress	Nasturtium officianale	Moderate	High
Spatterdock, Yellow cow lily	Nuphar sp.	Low	Low
Sedges	Cyperus sp.	Low	Low
Eurasian water milfoil	Myriophyllum spicatum	Moderate	Moderate
Frogs-bit	Limnobium spongii	Low	Low
Water hyssop	Bacopa	Moderate	Low
Eelgrass	Vallisneria americana	Low	Low
Watermeal	Wolffia sp.	High	Low

PUBLICATION DATE:  25/06/2008

RATING

AUTHOR:  Dr. Martin W. Brunson, Extension Leader/Fisheries Specialist - Mississippi State University Extension Service Information Sheet