The Effect of the Absence or Presence of Channel Catfish Males on Induced Ovulation of Channel Catfish Females for Artificial Fertilization with Blue Catfish Sperm

Female channel catfish Ictalurus punctatus were induced to spawn with carp pituitary extract either singly paired with channel catfish males in aquaria (males present) or stocked with multiple females in aquaria or tanks (males absent). There was no difference between ovulation rates of females induced to spawn in the presence or absence of channel catfish males (P = 0.57). Females hand-stripped with males absent produced more eggs per kilogram of body weight (4, 585) than females with males present (2, 942; P = 0.07). When females in the males-present treatment deposited eggs in the aquaria, which allowed observation of the readiness of females, the number of eggs available for stripping was reduced. There was no difference in fertilization rate between treatments when using sperm from blue catfish I. furcatus (P = 0.35). Females that ovulated with males absent produced a similar (P = 0.12) number of viable eggs per kilogram of female body weight as females that ovulated with males present (3, 809 and 2, 291, respectively). It may be commercially feasible to artificially produce hybrids of channel and blue catfish by using the methods demonstrated in this experiment. This study has shown that pairing channel catfish females with males is unnecessary to induce ovulation in females and that more eggs are available to the culturist for hybrid production when males are absent.