温度、盐度对龟足胚胎发育和幼虫生长的联合影响

Combined effects of temperature and salinity on embryonic development and larval growth of Capitulum mitella

龟足(Capitulum mitella Linnaeus)在我国主要分布于长江口以南海浪剧烈冲击的暴露型岩相海岸的中、高潮区,是一种颇具养殖潜力和市场前景的新品种。研究温度(24、27、30、33℃)和盐度(28,31,34)对龟足胚胎发育和幼虫生长的协同影响,可为龟足的人工育苗提供依据。结果如下(1):33℃-28温盐度组合胚胎发育时间最短144h,27℃-28温盐度组合胚胎相对孵化率最高。温度与盐度对胚胎发育时间没有显著影响;但温度和盐度对胚胎孵化率有极显著影响,温度与盐度间的交互作用显著。胚胎发育最适宜的温盐度组合是27℃-28。(2):27℃的3个盐度组、30℃-31温盐度组合无节幼虫持续时间最短。在同一盐度条件下以27℃的存活率较高,在同一温度条件下以盐度31的存活率较高,其中以27℃-31温盐度组合的存活率最高;存活率1和存活率2分别高达99.0%、90.7%。27℃-28、27℃-31温盐度组合变态率最高,变态率分别为81.8%、73.7%。34高盐组幼虫的存活率和变态率均很低甚至为零。温度和盐度对幼虫存活率和变态率有极显著影响,两者的交互作用极为显著。综合无节幼虫持续时间、存活和变态情况,27℃-31温盐度组合为幼虫生长发育的最佳组合条件。龟足胚胎发育、无节幼虫的生长和变态对温度盐度的敏感性有所不同,这是由龟足的自身繁殖特点及生活环境决定的。

The stalked barnacle,Capitulum mitella,is a sessile pedunculate cirripede that inhabits the exposed rocky intertidal frame,distributing south coast of the Changjiang Estuary in China.C.mitella is widely used as food in Fujian,Zhejiang and Guangdong.Because of being highly valued fishery resource and its economic importance,C.mitella will be a new breeding variety with considerable potential and market prospect.Temperature and salinity are known to regulate embryonic development,growth,survival and duration of larvae in many marine invertebrates.The combined effects of temperature and salinity on embryonic development and larval growth of C.mitella were investigated under controlled laboratory conditions,which could provide insight into reference for culturing of C.mitella.Four temperature including 24,27,30℃ and 33℃ as well as three salinity including 28,31 and 34 were selected.The results showed as follows.The embryonic development time was the shortest（144h） at 33℃-28,and the longest（216 h） at 24℃-34,24℃-31 of temperature and salinity.The embryonic hatching rate was the highest（100%） at 27℃-28,the lowest（52.1%） at 33℃-34 of temperature and salinity.Temperature,salinity and their interaction had significant affects on embryonic hatching rate,but had not significant affects on embryonic development time.The optimum rearing condition of temperature and salinity for embryonic development was 27℃-28.The fastest larval development（Nauplius II to cypris stage） occurred at 30℃-31 of temperature and salinity（7 days） and 27℃ regardless of variation in salinity at this temperature（8 days）.Nauplius duration lasted 11 days at 24℃-34 and 33℃-34.Larval survival rate was higher at temperature 27℃ for fixed levels of salinity,at salinity 31 for fixed levels of temperature.The maximum survival rate 1 and survival rate 2 were 99.0% and 90.7% respectively at 27℃-31 of temperature and salinity.Metamorphosis rate was higher at 27℃-28（81.8%）,27℃-31（73.7%） of temperature and salinity.When salinity was up to 34,larval survival rate and metamorphosis rate were very low or even zero.The factors of temperature,salinity had significant affects on larval survival rate and metamorphosis rate,with significant interaction between temperature and salinity on larval growth.Considering total nauplius duration,survival and metamorphosis,the optimal combination of temperature and salinity for the larval growth and development of C.mitella was at 27℃ and 31.Larvae of C.mitella to salinity and temperature was more sensitive than embryos.We assume that the different response to environmental factors between embryos and larvae of C.mitella is attributed to its reproductive characteristic and habitat.