During the period 1951–56, 127,430 pounds of panfish and trashfish have been removed with fyke nets from 45 ponds in Massachusetts in an attempt to improve gamefish populations. Removal has ranged from less than one to 146 pounds per acre annually. Data from four ponds ranging in size from 20 to 269 acres are presented in detail. Where removal was intensive, growth rates of panfish increased markedly. Growth rates of gamefish, especially chain pickerel and largemouth black bass, which were returned to the water, showed a slight decrease or no change. Older panfish, remaining after thinning operations, showed less increase in growth rate than did younger fish spawned during or after the operations. No major changes in species composition in favor of gamefish were apparent. It is concluded that the fyke netting has increased growth rates of the species being thinned but has not materially improved gamefish populations.