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<br />22 <br /> <br />Problems with the typical solutions <br />listed above have brought biological con- <br />trol of excessive algae to the attention of <br />fisheries managers of reservoirs, natural <br />water bodies, and aquaculture ponds. Re- <br />search has been done with phytophagous <br />fish (algae-feeders) for the control of nui- <br />sallce algae in Eastern Europe, Asia, the <br />Middle East, and to a lesser extent in the <br />United States. Investigators have found <br />positive results with Asian carp in situ- <br />ations where the fish do not compete <br />directly with other fish species for food or <br />habitat. <br /> <br />United States in algal control research, and <br />as a result, the fish are difficult to obtain <br />from a hatchery in this country. Bighead <br />carp are more commonly used, primarily to <br />increase production of catfish for aquacul- <br />ture by improving the water quality in <br />these systems. The silver and bighead carp <br />were obtained from a Missouri fish hatch- <br />ery, which agreed to spawn the fish for our <br />study. <br />Silver and bighead carp are endemic to <br />the large rivers of central/south Asia, east- <br />ern China and Russia. The fish are native <br />to rivers located from the Tropic of Cancer <br /> <br />Five hundred 6-lnch bighead carp were stocked into Tomlinson pond In Arvada, Colorado, during <br />March 1992. The algal research being done In the pond is in cooperation with Arvada/North Jeffco Parks <br />Department and Quality-Water Blosystems, a contractor specializing In biological control. <br /> <br />../tr!~' ~1r <br />~ .. <br />.:f1::~ <br /> <br /> <br />Nuisance algae such as these green mats covered a <br />large portion of the surface waters in the control <br />portion of Tomlinson pond during July. <br /> <br />Silver and Bighead Carp <br /> <br />Silver carp (Hypophthalmichthys molo- <br />trix) and bighead carp (Aristichthys <br />nobilis) were selected for our research <br />study because of their promising charac- <br />teristics. The fish controlled excessive <br />algae successfully in other investigations <br />where they were stocked as a poly culture <br />and in unequal numbers (i.e., 1,000 silver <br />carp, 500 bighead carp). Before the exotic <br />fish were brought into Colorado, the Divi- <br />sion of Wildlife granted approval for their <br />introduction into various ponds for re- <br />search purposes only. Only a few other <br />people have worked with silver carp in the <br /> <br />- <br /> <br />t. . <br /> <br />.. <br />.",;,- -" <br /> <br />-- <br />