Effects of temperature on intermolt period, growth rate and reproduction rate in Acanthomysis mitsukurii (Crustacea: Mysidacea)

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Effects of temperatures (9, 13, 17, 20, 23℃) on the production of Acanthomysis mitsukurii were investigated in the laboratory under unlimited food conditions. The intermolt period increased with body length (BL) and decreased with increasing temperature. Growth factor (the percentage increase in BL between successive molts) declined with BL and the rate of the decline increased with temperature increase. Mysids reached zero growth at a smaller size under high temperatures, hence the maximum size was largest at the lowest temperature. Growth models as a discontinuous stepwise process at each experimental temperature were developed using a regression equation between the intermolt period and BL, and between the growth factor and BL, and BL on Day 0. The incubation time of young in the marsupium was significantly related to the temperature but not to the female BL. Although the number of offspring per brood (brood size) was greater at lower temperatures, incubation time was shorter at higher temperatures, resulting in a greater reproduction rate (brood size/incubation time) at the higher temperatures. There were no differences in the productivity parameters between 20℃ and 23℃ and because the survival rate of juvenile mysids to maturation was lower at 23℃ than at 20℃, the optimal temperature for population production of this species was concluded to be approximately 20℃.
日本甲殻類学会の論文