几种生态因子对拟目乌贼胚胎发育的影响

Abstract

Sepia lycidas belongs to the genus Sepia,the family Sepiidae,the orders Sepioidea,and the class Cephalopoda.It is a warm-ocean demersal Cephalopoda with larger size,delicious meat and high nutrition value. It inhabits off shore waters at a depth of 15—100 m,and is mainly distributed from the Indian Ocean to the western Pacific. The average weight of Sepia lycidas was 0.6 kg after 4 months cultivation,and the heaviest young Sepia lycidas could reach 1 kg. Because of its short raising duration and high yield,raising Sepia lycidas has a high development potential in China. Ecological factor is one of the important factors for the growth and development potential in China. Ecological factor is one of the important factors for the growth and development of marine organisms. The impact of ecological factors on the embryonic development of Sepia lycidas was studied in this paper,which helps us to learn the ececological principle and mechanism between them and the environment better. In order to get the optimum salinity,photoperiod,hatching density and dissolved oxygen concentration of embryonic development of Sepia lycidas,their effects on embryonic development were investigated. Singlefactor test was used to study the effects of salinity( 18、21、24、27、30、33、36),photoperiod L ∶ D( 0 h ∶ 24 h、6 h ∶ 18 h、12 h ∶12 h),hatching density( 3、6、9、12、15 ind / L) on hatching rate,nurturing cycle,incubation cycle,completely absorked rate of yolk sac and weight of newly hatched larvae of Sepia lycidas embryos under indoor control condition. The results showed that the embryonic development of Sepia lycidas was significantly affected by salinity( P0.05). The suitable salinity for hatching ranged from 27.0 to 33.0 and the optimum salinity was 30.0. Hatching rate,nurturing cycle,incubation cycle,completely absorked rate of yolk sacwas and weight of newly hatched larvae were( 93.33±2.89) %,( 25.67±0.58)d,( 5.33±0.58) d,( 89.27±0.33) % and( 0.247±0.006) g under the optimum salinity respectively. Photoperiod had not a significantly effect( P0.05) on incubation cycle of Sepia lycidas,but had a significantly effect on other indicators( P 0. 05). The optimum photoperiod is L ∶ D( 6 h ∶ 18 h). Hatching rate,nurturing cycle,incubation cycle,completely absorked rate of yolk sacwas and weight of newly hatched larvae were( 80.33±2.89) %,( 35.67±0.57) d,( 4.67±0.57) d,( 82.18±7.72) % and 0.243±0.012 g under optimum photoperiod,respectively. The embryonic development of Sepia lycidas was significantly affected by dissolved oxygen concentration( P 0. 01). Embryos could not develop when Oxygen concentration in water is less than 5.55 mg / L. The embryonic development of Sepia lycidas was also significantly affected by hatching density when air was provided( P0.05). The suitable hatching density ranged from 3 ind / L to 9 ind / L and the optimum hatching density was 6 ind / L. Hatching rate,nurturing cycle,incubation cycle,completely absorked rate of yolk sacwas and weight of newly hatched larvae were( 96.67±2.89) %,( 29.67±0.58) d,( 5.67±1.15) d,( 89.65±0.31) %and( 0. 244 ± 0. 005) g under the optimum hatching density respectively. Taken together,our results indicated that the suitable salinity for hatching ranged from 27.0 to 33.0,optimum photoperiod was L ∶ D( 6 h ∶18 h),and suitable hatching density ranged from 3 ind / L to 9 ind / L,because of the high hatchability and post-hatching survival,and the fastest growth of hatchlings in these thermal regimes.