Font Size: a A A

Evaluation On The Effect Of Proliferation And Release Of Larimichthys Crocea In The Coastal Waters Of Jiangsu Province

Posted on:2023-10-06Degree:MasterType:Thesis
Country:ChinaCandidate:C W ZhuFull Text:PDF
GTID:2543306818992219Subject:Ecology
Abstract/Summary:PDF Full Text Request
Larimichthys crocea is one of the most important marine economic fishing fishes along the coast of Jiangsu Province.It is widely distributed in the Southern Yellow Sea,the East China Sea and the South China Sea.Before the 1970 s,Jiangsu Lvsi fishing ground was rich in natural resources of Larimichthys crocea,but the natural resources of Larimichthys crocea gradually declined and depleted due to overfishing and deterioration of habitat environment.In order to solve the problem of insufficient natural resources of Larimichthys crocea,Jiangsu Province has carried out the proliferation and release of Larimichthys crocea seedlings for decades,However,the of Larimichthys crocea is still recognized as the species with declining resources in the Yellow Sea.Therefore,it is particularly important to carry out scientific and quantitative evaluation of the proliferation and release effect of Larimichthys crocea,formulate scientific release strategies,and maintain the effectiveness of the germplasm resources of Larimichthys crocea,which can provide a scientific basis for the resource recovery of Larimichthys crocea and the sustainable development of fishery resources off the coast of Jiangsu Province.This paper is based on the bottom trawling investigation of fishery resources in the nearshore sea of Jiangsu,combined with the analysis of the otolith fingerprint markers,molecular markers and social survey results of Larimichthys crocea,this paper explores the application of natural resource changes,strontium fingerprint markers and molecular markers in the evaluation of the proliferation and release effect of Larimichthys crocea.The main findings are as follows:This study is mainly based on data from the 2016-2020 bottom trawling survey,the temporal and spatial changes of fishery species,resources,dominance and diversity level in Jiangsu coastal waters are analyzed,and the resources and diversity level of Larimichthys crocea stations are compared.From 2016 to 2020,a total of 176 species of fisheries were captured,including 97 species of fish,7 species of cephalopods,and 2 species of other classes.On the whole,except that the average resource in 2019 is high,the difference of average resource in other years is small,the annual average resource of fish shows a downward trend,compared with crustaceans,it shows an upward trend,and the difference of cephalopods is small.Compared with the seasons in the past five years,the Summer was highest on average,followed by autumn,spring;The average resource of each station in Nantong sea area is higher than that in Lianyungang and Yancheng sea areas.The average Shannon Wiener diversity index H ’is 2.51,the average marglef species richness index D is 1.96,and the average Pielou evenness index J’ is 0.59;There are 6 dominant species(IRI ≥1000)of fishery resources in the coastal waters of Jiangsu Province,namely Portunus trituberculatus,Collichthys lucidus,Miichthys miiuy,Larimichthys polyactis,Oratosquilla oratoria and Harpadon nehereus.From 2016 to 2020,a total of 10 stations in Jiangsu inshore fishery resources survey captured Larimichthys crocea,and the diversity level of capture stations was lower than the average diversity level of fishery resources survey in that month,but the resource quantity and resource density were higher than the average level.In conclusion,the proliferation and release of Larimichthys crocea played a good ecological and economic benefit in improving the natural population resources and fishing yield.Based on the detection results of labeled larvae of Larimichthys crocea and otolith element markers of 400 recovered Larimichthys crocea before release in 2019 in Jiangsu Province,the labeling situation of breeding and release labeled larvae of Larimichthys crocea and the labeling preservation and applicability of Larimichthys crocea in natural waters were analyzed.Through ICP-MS detection of release labeled seedlings and control seedlings,The seedlings of Larimichthys crocea treated with18 mg / L strontium ion formed obvious strontium fingerprint markers at the distance of 0.60 ~ 0.80 mm from the otolith core.The seedlings of the control group did not have strontium fingerprint markers at the distance of 0.60 ~ 0.80 mm.The marked seedlings randomly selected showed obvious markers,and the success rate of labeling was 100%;In 2019,41.5816 million Larimichthys crocea were released in Jiangsu Province,including 377200 labeled fish,accounting for 0.91%;From 2019 to 2020,8of the 400 Larimichthys crocea recovered in the marine investigation,recapture and social investigation in Lvsi,Rudong and Haimen have Sr / Ca ratio peaks 0.40 ~0.80 mm away from the otolith core,which can be identified as Larimichthys crocea marker fish,accounting for 2.0% of the total number of recovered samples,which is higher than the proportion of Larimichthys crocea marker fish proliferated and released in 2019;The otolith ages of these eight labeled Larimichthys crocea were identified,including 3 individuals at the 1st and 2nd instars and 2 individuals at the3 rd instar.The ratio of labeled Larimichthys crocea at all age levels and higher than the labeled release seedlings can indicate that the proliferation and release activities of Larimichthys crocea have a continuous supplementary effect on the natural population,Otolith fingerprinting with strontium element can be used as one of the basis for evaluation of proliferative outflow effect in Larimichthys crocea in Jiangsu Province.Based on the results of kinship identification of 82 Larimichthys crocea fry and116 recovered Larimichthys crocea samples before release,the applicability of molecular marker technology in the evaluation of proliferation and release effect of Larimichthys crocea in Jiangsu Province and the determination of other release fry except the labeled Larimichthys crocea fry in proliferation and release were analyzed.The results showed that,The number of mitochondrial DNA haplotypes in the recovered population and released seedling population of Larimichthys crocea were106 and 31,the number of polymorphic loci were 141 and 75,the haplotype diversity was 0.9984 ± 0.0014 and 0.8735 ± 0.0308,and the nucleotide diversity was 0.0217 ±0.0108 and 0.0141 ± 0.0072,respectively.A total of 133 haplotypes were defined in82 released seedlings and 116 recovered Larimichthys crocea,Among them,34 released seedlings shared 4 haplotypes with 5 recaptured Pseudosciaena crocea,which may be released Larimichthys crocea,which was further excluded by microsatellite molecular markers.A total of 78 alleles were detected among the 3 polymorphic macrocarp microsatellite loci screened.The observed heterozygosity was 1,the expected heterozygosity was 0.9038 ~ 0.9387(mean value: 0.927),and the polymorphism information content was 0.8834 ~ 0.9222(mean value: 0.909).There were no recaptured Larimichthys crocea with the same alleles in 34 released seedlings not excluded by mitochondrial DNA markers and 33 released seedlings in 5 collected Larimichthys crocea,It is not related to the Larimichthys crocea recaptured this time and is excluded;There are no released seedlings with the same allele in the three recaptured Larimichthys crocea,which are excluded.The remaining recovered Larimichthys crocea can find the released seedlings with genetic relationship.The alleles of the two at the three microsatellite loci are the same,which can be determined as the released aerospace.From 2019 to 2020,among the 116 Larimichthys crocea recovered from marine and social surveys in Lvsi and Rudong,two individuals related to released seedlings were detected,accounting for 1.72% of the total number of recaptured samples.Molecular marker technology can be used as a method to judge the unlabeled Larimichthys crocea,and strontium otolith fingerprint labeling technology is supplemented to make the evaluation of the proliferation and release effect of Larimichthys crocea more scientific and credible.
Keywords/Search Tags:Larimichthys crocea, proliferation and release, strontium otolith fingerprint, molecular marker
PDF Full Text Request
Related items