Growth and Survival of Walleyes Reared in Ponds Fertilized with Organic or Inorganic Materials

Abstract

Abstract Fry of walleye Stizostedion vitreum were reared for 40 d at a density of 16 fish/m3 in ponds fertilized with organic or inorganic matter and at 50 fish/ m3 with inorganic fertilization. Al the lower density, inorganic fertilization was more economical than organic fertilization, and fish survival was unaffected by fertilizer treatment. Although fish lengths were similar in both treatments, fish in the inorganically fertilized ponds gained less weight than those in the organically fertilized treatment. At the higher density, fish survival was unaffected, but growth was reduced so that the fish were unacceptably small for stocking. Fish production did not vary significantly among the treatments, but was lower at the higher density than reported in similar studies. Production may have been limited by low alkalinities in the ponds. Ponds receiving inorganic fertilizers had higher dissolved-oxygen levels than those fertilized with organic matter.