|关键词||许氏平鲉sebastes Schlegelii 增殖放流 遗传多样性 鱼类组成 Mtdna标记 微卫星标记|
|其他摘要|| 过度捕捞等因素导致了海洋鱼类种群衰退和资源量下降。增殖放流可以有效地增加渔业产量，并且修复渔业生态环境。许氏平鲉Sebastes schlegelii是重要的海水经济鱼类，也是进行人工放流的主要鱼种。本研究对2013年我国山东荣成俚岛湾许氏平鲉增殖放流前后该海域许氏平鲉群体遗传学及鱼类组成进行分析，对其增殖放流可能造成的遗传学等影响进行评估，以期为许氏平鲉种质资源保护、增殖放流及可持续利用提供基础数据。|
1、俚岛湾的鱼类资源分析。本研究于2013年5月-2014年11月间在俚岛湾利用定置网按季节进行鱼类样品采集，调查海域两年共获得鱼类样品20种，隶属于5目13科18属，鲈形目鱼类种数最多，占鱼类总种数的50.0%。根据相对重要性指数（IRI）分析显示，优势种为许氏平鲉和大泷六线鱼，这两种鱼类均为该海域进行增殖放流的理想鱼类。扩增了这20种鱼类的119条COI序列，可以成功区分所有鱼类，显示线粒体COI序列作为条形码分子标记在俚岛湾鱼类鉴定中的有效性；20种鱼的平均GC% 为46.8%，种、属、科、目内的平均K2P遗传距离分别为0.14%、5.17%、21.30%和 23.25%。水质参数对鱼类丰度影响的冗余分析（RDA）结果表明，温度对俚岛湾鱼类群落的影响最大；优势鱼种许氏平鲉和大泷六线鱼的分布受到温度、氧化还原电位ORP的正向影响，以及盐度和溶氧的负向影响。
2、许氏平鲉放流前后俚岛湾鱼类种类组成及其丰度变化的研究。结果显示放流前后俚岛湾鱼类种类基本未发生变化的，优势种均为许氏平鲉和大泷六线鱼。而均匀度与丰富度指数在放流前后也未发生明显的改变。同时，对荣成俚岛湾放流前后许氏平鲉群体进行形态学特征（全长-体重关系LWRs、全长-体长关系LLRs）、条件系数K及性比进行研究，结果显示俚岛湾许氏平鲉群体性别显著偏离1:1（1 M : 0.79 F），LWRs的r2均大于 0.95，b值变化范围为2.947 到3.277；LLR呈显著的线性相关。雄性中，K值变化范围为0.791到2.918；雌性中，K值变化范围为0.752到2.681。放流前后，俚岛湾许氏平鲉群体性别比例、LWRs、LLRs和K值均未发生显著变化。
3、增殖放流对许氏平鲉俚岛湾野生群体的遗传学影响分析。利用线粒体DNA（mtDNA）控制区部分序列及38对微卫星引物对俚岛湾放流群体以及放流前、后许氏平鲉野生群体进行了遗传多样性研究。获得的678bp的线粒体控制区片段定义了78个单倍型。放流群体的单倍型多样性指数h为0.902，核苷酸多样性指数为0.00483。放流前、后俚岛湾野生群体的h分别为0.970和0.939，核苷酸多样性指数分别为0.00581和0.00526。分子方差分析 (AMOVA) 结果显示，99%的变异来自于群体内的个体间，仅有1%的遗传变异来自于群体间。放流群体与俚岛湾放流前野生群体的遗传分化指数FST为0.01488。由以上结果可以看出，放流群体的遗传多样性低于野生群体，放流群体与野生群体间的遗传分化达显著水平（P<0.01），但分化程度较弱（FST<0.05）。放流前与放流后俚岛湾野生群体的遗传分化指数为-0.00404，表明放流前后不存在显著的遗传分化。微卫星分子标记的实验结果也证实了以上结果。微卫星分析显示，放流群体的有效等位基因数（Ne）为 4.76，多态信息含量PIC为0.674，平均期望杂合度（He）为0.697，平均观测杂合度（Ho）为0.668。放流前后俚岛湾野生群体的Ne、PIC、He和Ho分别为 6.01和5.82、0.698和0.716、0.735和0.754、0.709和0.741。AMOVA分析结果显示有91.54%的遗传差异来源于个体间，3.77%的遗传差异来自于群体内的个体间，仅有4.69%的遗传差异存在于群体间。放流群体与俚岛湾野生群体的FST为0.03980；放流前、后俚岛湾野生群体的FST为0.03359。两种标记的研究结果都显示，俚岛湾野生群体的遗传多样性高于放流群体，放流前后俚岛湾许氏平鲉野生群体的遗传多样性并未发生显著变化。由此说明，俚岛湾许氏平鲉的放流是可行的，但有必要对增殖放流的遗传学风险进行研究。
; Wild stock of marine fish is heavily depleted and resources have dramatically decreased due to a few factors like overfishing. Fishery resource enhancement and release is an effective method for restocking and enhancing fishery biomass, and repairing the marine fish ecological environment. The black rockfish Sebastes schlegelii, as an important commercial fish, has been one of important fish species for marine fishery stock enhancement. This study analyzed the changes of genetic impacts on wild stock and fish composition after S. schlegelii enhancement in Lidao Bay, Rocheng, China, in 2013. This study would provide basic data for resource protection, stock enhancement and sustainable restoration for S. schlegelii in this area.
1. The analysis of fish resources in Lidao Bay. Investigation of fish resources in Lidao Bay was carried out from May 2013 to November 2014. Fish samples were collected seasonally using stake nets. The results showed that there were 20 species of fishes were captured in Lidao Bay, belonging to 18 genus, 13 families and 5 orders. Among them, Perciform fish species, accounting for 50.00%, enjoys the highest amount in the total fish species. Index of Relative Importance (IRI) was used to determine dominant fish species, and the result showed that the S. schlegelii and Hexagrammos otakii are the dominant fish species in this area. And both were suitable for stock enhancement in this area. A total of 119 specimens collected from 20 different species were DNA barcoded using mitochondrial cytochrome coxidase subunit I (COI) gene. All fish species could be discriminated by their COI sequences, and DNA barcoding could provide sufficient information to identify and delineate fish in Lidao Bay. Average GC% content of the 20 fish species was 46.8%. Average Kimura 2-parameter genetic distances within species, genus, family, and order were 0.14%, 5.17%, 21.30%, and 23.25%, respectively. The effects of water quality parameters on Liadao Bay fish abundance were analyzed by redundancy analysis (RDA) method. The result showed that the most important factor affecting fish communities in this area was water temperature. The abundance of dominant fishes, S. schlegelii and H. otakii, was affected by positive influences of temperature and ORP, and by negative influences of salinity and DO.
2. The species and amount of fish in Lidao Bay before and after S. schlegelii stock enhancement were analyzed to learn the influences on fish community structure. The results showed that the fish species in this area don’t nearly change before and after stock enhancement, and the dominant species still were S. schlegelii and H. otakii. There were also no obvious changes in the evenness and abundance indexes before and after the stock enhancement. Meanwhile, the length–weight relationships (LWRs), total length (TL) – standard length (SL) relationships (LLRs) and Fulton's condition factor (K) of male and female S. schlegelii in Lidao Bay were comparised to study the biological effects stock enhancement exerts on natural stock. The results showed that there were more males than female (1 M : 0.79 F) in Lidao Bay. The LWRs were significant (P < 0.05) with all coefficients of determination (r2) values being higher than 0.95. The b value varied from 2.947 to 3.277. The LLRs for TL to SL, and vice versa, were all linear. The K values ranged from 0.791 to 2.981 in males and from 0.752 to 2.681 in females. There were no significant changes in these biological parameters of S. schlegelii stocks after stock enhancement.
3. The genetic impacts of S. schlegelii enhancement in Lidao Bay were investigated by using partial sequence data of the mitochondrial DNA control region and 38 microsatellite DNA loci. The 678-bp segments of the mitochondrial DNA control region were sequenced from 288 samples, which identified a total of 78 haplotypes. The haplotype diversity parameter (h) and nucleotide diversity parameter (π) in hatchery-released stock were 0.902 and 0.00483, respectively. Meanwhile, the h values in wild stocks before and after stock enhancement were 0.970 and 0.939, and the π values were 0.00581 and 0.00526, respectively. Analysis of Molecular Variance (AMOVA) indicated that 99.00% of genetic variation occurred within stocks and only 1% of genetic variation occurred between stocks. The Fixation index (FST) between hatchery-released stock and natural stock was 0.01488. The results showed that the hatchery-released stock was less diverse and diverged weakly but significantly from the natural stock before enhancement. And the FST between wild stocks before and after stock enhancement was -0.00404, showing that there was almost no significant difference between these two stocks. Above results were also confirmed by using microsatellite markers. According to analysis of microsatellite markers, the mean effective numbers of alleles (Ne) in hatchery-released stock was 4.76, mean polymorphism information content (PIC) was 0.674, observed heterozygosity (Ho) was 0.668, and the expected heterozygosity (He) was 0.697. In wild stocks before and after stock enhancement, the Ne, PIC, Ho and He values were 6.01 and 5.82, 0.698 and 0.716, 0.709 and 0.741, 0.735 and 0.754, respectively. AMOVA results indicated 91.54% of genetic variation occurred between individuals, 3.77% occurred between individuals within stocks, and only 4.69% occurred between stocks. The FST between hatchery-released stock and natural stock was 0.03980, and between the natural stocks before and after restocking was 0.03359. The results of the two markers showed that genetic diversity levels in natural stocks were higher level compared with hatchery-released stock, and the level of genetic diversity in the natural stocks was not significantly different from that before stock enchantment. Therefore, the restoration program for S. schlegelii in Lidao Bay is feasible. However, the consideration of the genetic risks of releasing hatchery-reared juveniles into the wild in stock enhancement is necessary.
|王丽娟. 许氏平鲉增殖放流对其荣成俚岛湾群体遗传多样性及鱼类组成的影响[D]. 北京. 中国科学院大学,2016.|