Home / Fisheries / Controlling Weeds / Biological Control
Aquatic Weed Control
Intro |
Identifying Weeds |
Controlling Weeds |
List of Common Weeds |
Control Methods
- Biological Control
- Physical Control
- Chemical Control
- Mechanical Control
- Grass Carp
Biological Control
Biological control uses an animal or other living organism to control the weeds. Biological control has many advantages over other weed control means. It takes much less human effort than most mechanical control means and does not require expensive and sometimes hazardous aquatic herbicides. And using animals provides longer-term control than other Triploid grass carp (white amur) from China are commonly used for aquatic weed control.
How much vegetation grass carp will consume depends on several environmental conditions, such as water temperature, water chemistry, and the kinds of plants available. Consumption rates also vary with fish size. For example, until they reach weights of about 6 pounds, grass carp may eat 100 percent of their body weight in vegetation per day. As they grow larger, consumption decreases; up to about 13 pounds, they will eat 75 percent of their body weight per day, and above 13 pounds, they slow down to about 25 percent of body weight per day.
Grass carp prefer soft, low-fiber aquatic weeds such as duckweed and various underwater plants. But grass carp cannot necessarily control some of the plant species they “prefer” to eat. These plants grow very quickly, and grass carp may not be able to eat them quickly enough. Duckweed is a good example of a plant that grass carp love but usually cannot control. One solution is to increase the density of grass carp, but this carries its own risks. In cases where 15 or more grass carp per acre are stocked, it is a good idea to remove many of these fish once weeds are controlled.