Growth characteristics of the hybrid between pinto abalone, Haliotis kamtschatkana Jonas, and exo abalone, H-discus hannai Ino, under high and low temperature

Rearing experiments have been done to compare growth rates in pinto abalone , Haliotis kamtschatkana Jonas, and ezo abalone, H. discus hannai Ino. The growth rate in shell length of juvenile pinto abalone was superior to that of ezo abalone at water temperatures below 7 degrees C. However, the growth rate declined above 17 degrees C and was lower than that of ezo abalone. T he hybrid cross between the female of ezo abalone and the male of pinto aba lone was obtained but with low fertilization (20%). The reciprocal cross wa s never successful. The growth rate of the hybrid was superior to the paren tal species below 18 degrees C and moderate between parental species under 8 degrees C. Isozymic analysis confirmed that genetic hybridization occurre d in this cross, on the basis of the results of electropherograms of the hy brid and its parental species.