International Journal of Fisheries and Aquatic Research

Authors
Neetha Nandanie Punchihewa

Abstract
The effects of seasonal temperature on intra-marsupial development, growth and survival of two mysid species, Tenagomysis novaezealandiae and T. chiltoni, in the Auckland region are reported using laboratory studies. Replicated experiments at multiple temperature treatments were selected with reference to the average temperatures in the field along with the ambient temperatures around Auckland over the course of four seasons: winter, 13 ± 1°C, spring and autumn, 18 ± 1°C and summer, 23 ± 1°C. Higher temperatures accelerated the incubation period and growth whereas it decreased the survival of mysids. Tenagomysis chiltoni exhibited a longer incubation period than T. novaezealandiae at all temperatures. The warmer temperature accelerated the growth rate of immature individuals than that of mature individuals. Further temperature enhanced the faster maturation. In addition to this, shorter generation time was also observed at higher temperatures. Both species showed multivoltine life cycles and produced up to five generations within their life time. Life span varied according to the seasonal cohort, shortest in summer and longest in winter. Their maximum life span was eight months for T. chiltoni, and seven months for T. novaezealandiae, that were born during autumn and winter. To have an enhanced growth and survival, temperature is the most contributing factor to be considered.