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Stocking rates provided from this model are determined so the regulated level of aquatic vegetation (10-25%) can be achieved three to four years a&:r grass carp are stocked. If vegetation regulation using grass carp is sought earlier by stocking more fish than recommended by the model, the consequences could be total elimination of aquatic vegetation within the first four years. The Final Stocking Suggestions include some alternatives for the aforementioned situation. For irrigation and water storage impoundments, "swimming hole" ponds, or decorative ponds (such as those in housing developments or golf courses), elimination of aquatic vegetation may be desirable. For these situations, the model provides stocking rate guidelines for the elimination of aquatic vegetation within the first or second year. However, for the above situation, the rapid consumption of large quantities of vegetation by grass carp mu cause plankton blooms resulting in poor water quality and a loss of water clarity within the first year or two. The model included adjustments and refinements to a basic grass carp stocking rate. The adjustments are included to determine the optimum number of grass carp to stock under the given conditions, thus obtaining the best return for your investment. Any temptation to stock a few more grass carp per acre should be restrained for the following reasons: 1) 8-12 inch grass carp generally cost from $6-8/fish (triploids cost about $1 more). Stocking a few more fish per acre could add $20-30 to the per-acre cost; 2) these stocking rates and adjustments were designed as conservative rates with the idea that ~ three or four years, more grass carp could be stocked if aquatic vegetation target levels were not achieved. INSTRUCTIONS FOR USING THE MODEL This model is based on four attributes which we have deemed important in determining grass carp stocking rates. In addition, guidelines are given to adjust the grass carp stocking rate to the management objective for the lake or pond. Two additional modifying factors are suggested for final refinement to the model's recommended stocking rate. The Grass Carp Stocking Rate Worksheet provided at the end of this paper should be removed for use now. Instructions in this model that are "boxed-in" indicate where a decision must be made and transferred to the Grass Carp Stocking Rate Worksheet. After transferring the requested information, turn to the next page in the model. Certain information is assumed to be known about a particular lake; however, for other items which may not be known (e.g., aquatic vegetation species, management objectives), a general value may be assigned, as per instructions. The right arrows ( ~) on the Worksheet indicate that a value from the identified page should be recorded here. All the information you provide is used on the Worksheet for the determination, adjustment, and refinement of a grass carp stocking rate best suited for your particular lake. 35