Outdoors: Proper pond treatment
Aquatic plants are beneficial to fish communities because they supply oxygen when photosynthesizing, and provide food and cover. However, overabundant vegetation can interfere with access, angling success, and in certain cases compete for oxygen, thus lowering the performance of a fishery.
As a general rule, plant coverage of up to 30 percent of the pond’s surface area should not be of concern unless you are more interested in how the pond looks or the vegetation is interfering with some other use of the pond. Anything more than this and you may want to consider one of a suite of control measures.
The first step is to identify the plant(s) causing the problem since several control options are available for different species.
Try using the Pond Manager Diagnostic Tool on the Texas Parks and Wildlife Department (TPWD) web site or take a sample to the fisheries office in San Marcos.
One way of dealing with overabundant vegetation is to use mechanical methods (rakes and mechanical harvesters). This can be labor intensive or costly.
Another option is to use herbicides. There are a variety of different types of these chemicals and they can be very effective over the short term.
Chemical treatment can become expensive depending on treatment coverage and since there are restrictions and important safety compliances to consider, you might end up having to contract a licensed applicator to do it.
A biological method of controlling certain aquatic plants involves the use of sterile grass carp. These plant eating fish are non-native and a permit is required from TPWD before they can be stocked. The permitting process allows TPWD to keep track of the location and number of grass carp stocked in Texas. These grass carp are unable to reproduce so their impact will be limited by life span. If the pond has an overflow it may be necessary to construct a barrier to prevent your investment from escaping and to protect other waterways where plant control by the escapees is not desired.
The TPWD web site provides detailed information to guide you through all the options to determine which method is best suited for your particular situation and budget (www.tpwd.state.tx.us).
Remember, successful aquatic plant management can be a work in progress; whichever method is used, you may need to reapply after a certain period of time.
Mukhtar Farooqi is a fisheries biologist with TPWD. For more information about fishing opportunities and fisheries management, contact the San Marcos inland fisheries office at (512) 353 0072 or visit our Facebook page (www.facebook.com/Texas Parks and Wildlife Inland Fisheries San Marcos).