A biological control is when one form of life is used to control another or the balance of life is manipulated in some way to adversely affect an undesirable pest. A good example of this was when over the years we almost totally wiped out the wolf population here in the United States, the result was an extreme over population of Deer, by this example we can see why it is important to be very careful when considering the use biological controls, the results sometimes can be worse than the orginal problem.
The most common form of biological control that is used in ponds and lakes is a fish called the White Amur (Grass Carp). The White Amur is legal for use as a biological control of weeds in a number of states around the USA, in the states where it is legal normally only the Triploid (Sterile) form of this fish can be sold, the Diploid form that can reproduce is generally illegal everywhere, for the fear of this fish getting into natural lakes destroying all the natural vegetation and ruining the environmental balance of these waters. In most states where the White Amur is legal, the sale of these fish are very closely regulated, in states where they are not legal the penalties for their possession can be very severe.
Whether the White Amur is something that you want to consider for your pond or lake, if you live in a state where they are legal, depends on what you use the pond or lake for and how you want it to look. Most states where this fish is legal have recommended stocking rates, if these stocking rates are exceeded, this can result in total eradication of all rooted plant life in the pond or lake and can result in severe algae problems. The White Amur have been around for many years and the controversy as to whether or not they are good or bad has been around for as many years and is still a very controversial issue. One thing that is very clear, there is much incorrect information that has been made available to the general public, the most common rumor is that this fish is the cure all for all forms of vegetation, you just put them in and you will never have any more weed or algae problems, this simply is not true.
Our position here at Aquatic Systems is that the White Amur is neither good or bad, it is a fish that eats rooted aquatic vegetation, that doesn't care for the various forms of algae. Before you consider stocking this fish, make sure to check with your states conservation agency to see if they are legal in your state, here in Wisconsin they are illegal and the penalties for their possession is quite severe. If you have any questions or would like to discuss the use of the White Amur for your pond or lake, please give us a call or drop us a line.
Barley Straw
Barley Straw has been tested in Enland by the Centre for Aquatic Plant Management for the control of planktonic and filamentous algae. This testing has been on going over the last 15 years. Barley Straw and other straws have been used sporadically here in the United States, with very mixed results. We attribute the poor results here in the U.S.A. to very limited information on application rates and techniques. A recent posting (11/06/97) on Ponds-L (our pond and lake management discussion group) from Dr. Jonathan Newman a Senior Research Scientist at the Centre of Aquatic Plant Mangement encluded a very detailed report on how to use Barley Straw for algae control. We feel that this report will greatly increase the success of Barley Straw usage here in the United States. To view or print out this report click on the button below.
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