The Economic Impact of Restricting Use of Black Carp for Snail Control on Hybrid Striped Bass Farms

Abstract

Black carp Mylopharyngodon piceus have been used in the U.S. for several decades for snail control in fish ponds. Recent concerns over the potential environmental effects of escaped fish have resulted in proposals to list black carp as an injurious species. A mixed-integer programming model was extended to evaluate the farm-level economic effects of restricting access to black carp for those farming hybrid striped bass (white bass Morone chrysops × striped bass M. saxatilis). The alternatives evaluated included (1) no snail control, (2) chemical control with hydrated lime, (3) chemical control with copper sulfate, and (4) biological control with redear sunfish Lepomis microlophus. Lack of access to black carp to control snail populations will reduce the marketability of food-size hybrid striped bass and will reduce the supply of hybrid striped bass fingerlings. Each 10% decrease in the marketability of hybrid striped bass food fish decreased net returns above variable costs by US$2,987/ha. Each 10% reduction in the supply of fingerlings further reduced net returns above variable costs by $1,107 to $1,855/ha. Net returns were lower as fingerling price increased with fingerling shortages after the first year. The industry standard of using black carp was the most cost-effective strategy. In the long run, based on the projections of our model, even with adoption of the alternative treatments analyzed in this study, small farms would go out of business, medium farms would suffer losses of 47% to 59%, and large farm would incur losses ranging from 33% to 41%. The total annual fish sales lost as a result of restrictions on the use of black carp were estimated to be $4.7-$11.96 million/year; with multiplier effects, total economic losses would be $16.45−$72.9 million/year.