Study On The Spawning Activity Monitoring In Rare Minnow(Gobiocypris Rarus) Based On Environmental DNA And RNA

Monitoring fish spawning activitiy is crucial in managing fishery resources.Although traditional monitoring method are effective,it can be damaging to fish habitats and require significant time and labor.To address these challenges,emerging environmental nucleic acid(e NA),such as e DNA and e RNA,have gained popularity as alternative or complementary method for monitoring biodiversity.e DNA has been successfully used to monitor fish spawning activity,but the potential of e RNA for this purpose remains untapped.Several issues require exploration,such as what’s the primary origin of e NA during spawning? In terms of e RNA and e DNA which one performs better in monitoring fish spawning activity?To address these concerns,we employed e DNA and e RNA,combined with q PCR,to detect e DNA and e RNA concentrations during the spawning period of the rare minnow(Gobiocypris rarus).Our study aimed to explain the origin of e NA during fish spawning activity,evaluate the feasibility of using e DNA and e RNA to monitor spawning activity,and compare the effectiveness.Our results provide a theoretical basis for the practical application of e NA.1.Origin of genetic material during G.rarus spawning activity:To identify the origin of e NA during the G.rarus spawning period,we collected G.rarus reproductive material such as sperm and oocyte fluid.Then used q PCR to detect e DNA concentrations based on the mitochondrial Cytb(cytochrome b)gene fragment,as well as e RNA concentrations based on the female-biased expression gene Cyp19 a and the male-biased expression gene Dmrt1.Our experimental results indicate that both sperm and oocyte fluid may contribute to e NA during G.rarus spawning activity.2.Monitoring the G.rarus spawning cycleTo monitor the G.rarus spawning activity cycle,using the mitochondrial Cytb gene and sex-biased expression genes(Cyp19a and Dmrt1)as genetic markers to detect e NA concentration for seven consecutive days.The study demonstrated that e RNA and e DNA were effectively to monitor G.rarus spawning activity.Analysis the e RNA concentrations of Cyp19 a and Dmrt1 genes which revealed that the Dmrt1 gene marker outperformed the Cyp19 a gene marker.Furthermore,e DNA and e RNA concentrations increased gradually from day 1 to day 5,reaching a peak on the 5th day which consistent with the spawning cycle of G.rarus.3.Monitoring G.rarus e NA concentration before and after spawningTo determine the timing of G.rarus spawning,we systematically collected water samples before and after spawning time point to detect e NA concentration which used the mitochondrial Cytb and Dmrt1 genes as markers.Our results revealed that e DNA and e RNA concentrations were higher after than before spawning.Comparing the concentrations of e DNA and e RNA at various time points of after spawning,we observed that e RNA concentration peaked at 4 hours after chasing,whereas e DNA concentration peaked at 20 hours.The high turnover rate of e RNA in the aquatic environment suggested that G.rarus started spawning at 4 hours after chasing.These findings emphasis that e RNA can perciously monitoring fish spawning activity.In summary,this study demonstrated the feasibility of using e DNA and e RNA to monitor G.rarus spawning activities,using mitochondrial Cytb genes and sex-biased genes.This provides a solid theoretical basis and good examples for using e NA monitoring fish spawning and fisheries resource management.