温度对中国鲎幼体蜕壳及成活的影响OA北大核心CSTPCD

The resources of Tachypleus tridentatus face the risk of depletion owing to habitat destruction and overfishing.Implementing artificial cultivation of large-sized juveniles and releasing them into suitable breeding grounds is an effective measure for restoring the population of T.tridentatus.This study used a self-designed cultivation system to rear horseshoe crab larvae and juveniles under controlled laboratory conditions.The impact of four distinct water temperatures(25,28,31,and 34 ℃)on molting rates,molting duration,and mortality rates of various instar stages was compared.After 120 days of cultivation,there were no significant differences in the total survival rates of larval and juvenile horseshoe crabs across different temperature groups(P＞0.05).However,higher water temperatures significantly facilitated the molting of larval and juvenile horseshoe crabs.At the end of the experiment,most of the juveniles in the 34 ℃ group had transitioned to the 4th instar stage,with a few individuals having already progressed to the 5th instar stage.In contrast,most individuals in the 31 ℃ group were observed to be at the 4th instar stage.In the 28 ℃ group,a predominant number were observed at the 3rd instar stage,with a few individuals progressing to the 4th instar.Within the 25 ℃ group,most individuals were observed at the 2nd instar stage,with only a few progressing to the 3rd instar.During the experimental period,the mortality rate of the 1st instar larvae ranged from 6.00％to 19.33％.Among them,the mortality rate of the 1st instar larvae in the 25 ℃ temperature group was significantly higher than that in the 31 ℃ and 34 ℃ groups(P＜0.05),while no significant difference was observed among the other temperature groups(P＞0.05).The mortality rates of the 2nd to 4th instar juveniles were not significantly different among the various temperature groups(P＞0.05).Significant differences were observed in the earliest molting times of the 1st instar stages among the various temperature groups(P＜0.05),with a noticeable trend of an earlier onset of molting at higher water temperatures.The development time required for each instar stage during the 2nd and 4th stages was estimated to range between 27 and 43 days,based on the weighted average time and earliest molting time of each instar stage,under temperatures ranging from 25 ℃ to 34 ℃.The influence of temperature on the development time of the 1st instar larvae was greater than that of the 2nd and subsequent instar juveniles.The comprehensive analysis indicated that increasing the temperature within the appropriate range can effectively promote the molting of T.tridentatus,both 31 ℃ and 34 ℃ can achieve excellent cultivation effects.These results suggest that large-scale indoor cultivation of large juvenile horseshoe crabs is feasible.Additionally,it is advisable to rear the larvae at higher temperatures immediately after hatching to facilitate their development into the 2nd and subsequent instars as quickly as possible,thereby preventing them from entering a diapause state at low temperatures.