基于形态测量和DNA条形码的中国鲻科鱼类分类研究

为探讨中国鲻科鱼类的分类地位,对采自中国8省27个地点的7种鲻科鱼类226个样本的40项测量数据进行了聚类、主成分与判别函数分析;测定了其中57个样本的标准条形码序列,结合Genbank下载的9种鱼类27条序列,构建基于K2P模型的邻接树,并进行遗传距离的计算和ABGD分析。结果发现,在形态方面,不同物种在主成分及判别函数散点图中重叠部分较大,表明对鲻科鱼类的鉴定不能仅依据单一的量度特征。在分子方面,14种鱼类聚类成12个明显的分支,分支间平均遗传距离17.14%(7.26%~23.94%),约为分支内平均遗传距离0.24%(0~1.5%)的71倍。其中,Liza sp.A、鮻(Liza haematocheila)、大鳞鮻(Liza macrolepis)、绿背鮻(Liza subviridis)、粒唇鲻(Crenimugil crenilabis)、黄鲻(Ellochelon vaigiensis)、鲻(Mugil cephalus)、帕氏凡鲻(Moolgarda pera)各自独立成支,支持其物种有效性。灰鳍鮻(Liza melinopterus)、棱鮻(Liza affinis)、长鳍莫鲻(Moolgarda cunnesius)、圆吻凡鲻(Valamugil seheli)、Liza sp.B、Liza sp.C出现混杂。推测Genebank下载的灰鳍鮻Lizamel Y.Lei Z1隶属棱鮻,Liza sp.B与Liza sp.C是同一物种,圆吻凡鲻及长鳍莫鲻为同种异名,但要排除其中出现杂交的可能则需结合核基因的进一步分析。鲻分成了2组,组间平均遗传距离2.44%约为组内平均遗传距离0.08%的31倍,高于一般物种的种内遗传距离(2%),表明存在隐藏的多样性。综上所述,鲻科鱼类外部形态保守,需结合DNA条形码分析提高鉴定的准确性。     

基于线粒体COⅠ基因的中国近海棱鳀属鱼类DNA条形码

为明确中国大陆近海棱鳀属鱼类的分类地位,采用国际通用的COⅠ基因5'端652bp序列作为DNA条形码,对中国近海棱鳀属全部6种鱼类62尾标本进行鉴定分析。结果发现,所分析样品的序列碱基组成为T:29.0%,C:26.3%,A:25.3%,G:19.4%,A+T含量(54.3%)高于G+C含量(45.7%),转换/颠换率为3.76。6种棱鳀属鱼类组成5个自展支持率为100%的分支,除黄吻棱鳀和中颌棱鳀各为单系但聚合为一支外,其余4种均独立成支;分支内与分支间平均遗传距离分别为0.2%(0.0%~0.4%)和17.7%(15.7%~19.0%)。赤鼻棱鳀、汉氏棱鳀、杜氏棱鳀和长颌棱鳀均符合Hebert提出的种间遗传距离(15.7%~18.6%)大于或等于10倍种内遗传距离(0.0%~0.3%)的标准,确定了它们的物种有效性。黄吻棱鳀和中颌棱鳀的种内遗传距离皆为0.1%,与其他4种棱鳀的种内遗传距离处于同一水平;但二者种间遗传距离仅为0.6%,明显低于其他物种间的种间遗传距离,属于一般物种的种内遗传距离范围,表明二者亲缘关系很近;由于外部形态存在一定的差异,且在分子系统树上各为单系,二者可作为同一物种的2个不同亚种处理,但也不排除是2个近期分化形成物种的可能,在资源管理上应作为2个不同的进化显著单位分别加以管理。     

官井洋种群网箱养殖大黄鱼的形态特征与生长式型

测定和研究了闽-粤东族官井洋种群养殖大黄鱼群体的形态特征与生长类型,并与文献报道的其亲本野生大黄鱼群体的形态特征进行了比较。结果表明:养殖大黄鱼的眼径/头长和体高/体长的比值普遍大于野生大黄鱼,而吻长/头长和眼后头长/头长的比值普遍小于野生大黄鱼。同时,养殖大黄鱼群体的眼径/头长、吻长/头长和头长/体长三项比值具有随着鱼体体长的增长而逐渐减小的特点。养殖大黄鱼体长与体重、体长生长与养殖时间的关系分别为:W=0.0195L2.9775(R2=0.9959)、y=-0.0259x2+1.7125x+4.1534(R2=0.989),鳔重与体重的比值为0.61%~2.26%,月平均鳔重指数1.08%~1.85%。     

1～2龄裸盖鱼形态特征及其相关参数分析

采用常规测量方法,以30尾全长35~50 cm,体质量400~600 g的养殖裸盖鱼(Anoplopoma fimbria)为实验材料,对其外部形态、可数可量性状及消化道结构进行观察和测量,初步研究了裸盖鱼的种质特征。裸盖鱼呈梭型,背面为青灰色,腹面为白色,全身覆鳞;第一背鳍16~18,第二背鳍12~14,腹鳍6~7,胸鳍14~16,臀鳍15~16,侧线鳞144~170,上鳃耙5~6,下鳃耙14~16,脊椎骨57~61,幽门盲囊4~6;全长/体长1.15±0.02,体长/体高5.27±0.08,体长/头长3.06±0.08,头长/吻长3.21±0.05,尾柄长/尾柄高3.19±0.17,体长/尾柄长5.46±0.20,头长/眼间距3.26±0.28,头长/眼径为6.73±0.31,肠长/体长为1.18±0.17,肠重/体重0.048±0.004,内脏重/体重0.103±0.014。1~2龄裸盖鱼种质特征研究结果可为裸盖鱼的育种提供基础数据。     

池养罗氏沼虾形态参数之间关系的初步研究

形态关系在甲壳动物的生长特性、遗传育种、种群资源评估和分类学研究中具有重要作用,已受到广泛重视。2015年5月至9月开展了罗氏沼虾土塘养殖实验,期间采集样品321尾,开展了罗氏沼虾形态关系的研究。结果表明,罗氏沼虾长度性状之间呈线性相关,各拟合方程差异极显著水平(P0.01),相关系数在0.943 4~0.997 5之间;额剑长(rostrum length,RL)分别与头胸甲长(carapace length,CL)、头长(head length,HL)、腹长(abdominal length,AL)、体长(body length,BL)和全长(total length,TL)的比值在BL为1~4 cm范围内呈现上升趋势,4 cm以后比值逐渐下降;CL分别与HL、AL、BL和TL的比值在BL达4 cm之前基本呈下降趋势,在BL达4 cm后呈现上升趋势;HL分别与AL、BL和TL的比值均呈现上升趋势;AL与BL或AL与TL的比值逐步下降,说明随着BL的生长,AL所占的比例逐步减少,与CL/BL比值逐渐增大相互吻合;BL/TL在BL达4 cm之前呈下降趋势,4 cm之后逐步上升,趋势平缓。各长度参数与体重之间呈幂函数相关。本研究基于形态性状测量数据,得出池养条件下罗氏沼虾额剑长、头胸甲长、头长、腹长、体长、全长之间以及各长度性状与体重之间的相互关系,有助于充实罗氏沼虾的基础生物学资料,为养殖生产实践提供科学指导。     

松浦镜鲤与德国镜鲤选育系(F_4)的可量性状、鳞片数比较

对松浦镜鲤(SP)和德国镜鲤选育系(F4)(DJ)的可量性状及体表鳞片数进行比较,SP与DJ的可量性状与体表鳞被存在差异.SP的体长/体高(2.44±0.15)、头长,眼间距(2.24±0.08)明显小于DJ,体长/头长(3.86±0.20)、头长/吻长(2.99±0.23)明显大于DJ,SP体表的鳞片数明显少于DJ.结果表明,从DJ到SP遗传选育过程中,体型和鳞片的变化已达到了选育目的.     

山东近海习见鱼类DNA条形码及其电子芯片分析

从GenBank下载到13目50科73属77种山东近海鱼类的线粒体细胞色素c氧化酶I(CO I)序列,通过分析其遗传距离及系统进化,并基于CO I序列筛选物种特异性探针来分析DNA芯片技术在进行物种鉴定时的可行性。结果表明,在CO I基因DNA条形码的分析中,77种鱼类的种间遗传距离(平均0.117)明显大于种内遗传距离(平均0.0034),且每个物种的不同个体在进化树上都能聚在一起,提示DNA条形码能全部区分77个物种;根据CO I基因设计的用于芯片的特异性探针中,77个物种最终有64个可以筛选出物种特异性探针,占总物种数的83.1%,本研究旨在为山东近海鱼类物种鉴定提供了技术支持。     

基于线粒体COⅠ基因序列的DNA条形码在中国南海绯鲤属鱼类鉴定中的应用

为探讨COⅠ基因作为DNA条形码对绯鲤属(Upeneus)鱼类鉴定的有效性,明确物种的分类地位,通过COⅠ基因5'端652 bp序列研究中国南海绯鲤属的黑斑绯鲤(Upeneus tragula)、马六甲绯鲤(Upeneus moluccensis)、纵带绯鲤(Upeneus subvittatus)、黄带绯鲤(Upeneus sulphureus)、吕宋绯鲤(Upeneus luzonius)以及条尾绯鲤(Upeneus bensasi)6个种56 ind标本的标准DNA条形码序列的种内种间遗传距离,并构建分子系统树。研究表明:所测样品的碱基组成为T:29.2%,C:29.6%,A:21.4%,G:19.8%,A+T含量(50.6%)略高于G+C含量(49.4%),转换/颠换率为3.08。6种绯鲤属鱼类组成5个自展支持率为100%的分支,其中黑斑绯鲤和马六甲绯鲤混杂分布于同一分支上,其余4种绯鲤独自成支;分支间平均遗传距离10.10%(8.60%~12.40%),是分支内平均遗传距离0.18%(0.00%~0.30%)的56倍。纵带绯鲤、黄带绯鲤、吕宋绯鲤、条尾绯鲤种间平均遗传距离为10.70%(8.80%~12.40%),约为这4个种种内平均遗传距离0.125%(0.00%~0.20%)的85倍,种间遗传距离大于种内遗传距离的10倍以上,确定了它们的物种有效性。黑斑绯鲤和马六甲绯鲤种内遗传距离分别为0.40%和0.20%,与其它4种绯鲤为同一水平;但种间遗传距离仅为0.30%,属于一般物种的种内遗传距离范围,因此推测二者或为同一物种,但还需从形态学和基因组序列分析等方面加以进一步确证,其是否受到种间杂交和近期辐射进化的影响也需要今后更多的研究。标准的DNA条形码虽然能够有效地区分中国南海绯鲤属鱼类中的纵带绯鲤、黄带绯鲤、吕宋绯鲤和条尾绯鲤,但DNA条形码对黑斑绯鲤和马六甲绯鲤的鉴定与形态学的鉴定结果不一致,表明在物种鉴定时,母系遗传的线粒体COⅠ基因有时需要结合其它核基因分子标记或生态调查资料加以辅助。     

人工培育秋大麻哈幼鱼的生长与形态研究

通过对在淡水中培育大麻哈幼鱼生长和形态测定发现:大麻哈幼鱼在2.5%日投喂量时特定生长率较高;大麻哈幼鱼体重与体长的关系符合幂函数,其关系式为W=0.661 L2.1635;随着大麻哈幼鱼的生长,其肥满度有所增加,但增加幅度较小;全长/体长、体长/头长、背吻距/背尾距的比值较体长/体高、头长/吻长、头长/眼径和头长/眼间距的比值变化小,背吻距/背尾距的比值接近1,而大麻哈鱼生殖群体的比值在1.13～1.31之间.     

黄海中南部狮子鱼种类的分析

于在黄海中南部海域采集的23尾体色花纹各异的狮子鱼标本，利用形态学和线粒体DNA细胞色素氧化酶Ⅰ亚基因(COⅠ)相结合的方法，对黄海中南部海域狮子鱼种类进行了分析。结果显示，22尾标本在可数性状和可量性状，如背鳍、尾鳍、臀鳍、胸鳍、幽门盲囊、头长/体长、头长/吻长、眼间隔/眼径、体高/体长等，属于细纹狮子鱼的范畴。其中4尾标本体表覆盖明显黑褐色横斑。5尾体表覆盖不规则斑纹，眼部存在放射性白色条带，头部及尾部存在明显的纵纹。9尾在头部或体侧具有褐色或者黑褐色细点，臀鳍黑色，尾鳍基部有1白斑。4尾体表尾红褐色，具有纵行细纹，背鳍、尾鳍、臀鳍及胸鳍外缘灰黑色；另1尾根据可数性状判断，其属于网纹狮子鱼，头部和体背部具有大小不等的白色小圆斑，尾长形、后端圆凸，背鳍基部两侧具有6–7个密集的斑点。COⅠ分析也具有相同的结果，其中22尾细纹狮子鱼之间的遗传距离为0.002–0.003，与网纹狮子鱼的遗传距离为0.134，与其他种类如戴氏狮子鱼、细尾狮子鱼、光皮狮子鱼等的遗传距离较近，为0.057–0.067。     

Phylogenetic relationships in grey mullets (Mugilidae) in a Tunisian lagoon

The Mugilidae family is an important fish group representing a major source for fisheries and aquaculture. In the south Mediterranean bank, no data are available on this fauna, except for some morphological studies on Tunisian samples. In this study, 16 allozymic loci were used to investigate the phylogenetic relationships within Tunisian mugilids. The results obtained from Hergla lagoon samples highlight five operational taxonomic unit corresponding to the well‐known species (Liza aurata, Liza ramada, Liza saliens, Chelon labrosus, Mugil cephalus). Several loci appeared to be diagnostic of these species, but in contrast to Greek mugilid samples, we did not find any diagnostic locus fixed differently for the five species. These results can help aquaculture units to identify accurately the mullet species they subsequently use for stocking aquaculture ponds and inland waters. However, species identity represents very important information, as each species has a different growth rate and salinity tolerance. On the other hand, when compared with North Mediterranean Mugilidae analysed until now, Tunisian samples show a genetic differentiation that could be related to different physicochemical conditions between the North and South banks, similar to those recorded in the eastern and western two Mediterranean basins separated by the Siculo‐Tunisian strait. In addition, this study confirms the morphological taxonomy, except for the subdivision of the Liza genus into two sub‐genera. The phylogenetic tree is in agreement with that on Languedoc Mugilidae samples (France), indicating that the subdivision of the Liza genus into two sub‐genera appears to be without any genetic base.     

Body composition of Mugil cephalus,Liza dumerili,Liza richardsoni and Liza tricuspidens (Teleostei: Mugilidae) caught in the Swartkops Estuary

Body composition (protein, fat, ash and moisture) and energy content of four mullet species Mugil cephalus, Liza dumerili, Liza richardsoni and Liza tricuspidens were determined monthly for 13 months in specimens taken from the Swartkops Estuary. Six size classes (<2.5, 2.6–6.0, 6.1–10.0, 10.1–15.0, 15.1–23.0 and > 23 cm SL) were analysed separately. Statistical analyses of results could only be performed on three size classes of M. cephalus, L. dumerili and L. richardsoni due to inavailability of fish during certain months. Regression equations were calculated for those body components that were significantly correlated, viz.: energy and moisture, fat and moisture, protein and moisture and energy and fat. The influence of species, size as well as seasonal effects and reproductive cycle on body composition were investigated. It was found that in general Liza dumerili had the lowest mean body energy and fat values and Liza tricuspidens the highest. Smaller size fish were lower in energy and fat and larger size fish lower in moisture. Overall mean values showed that body energy reserves were the highest during the winter. Sexually mature specimens of Liza dumerili showed a build-up of energy before the commencement of the spawning season.     

Chemical composition of alimentary canal contents of mullet (Teleostei: Mugilidae) caught in the Swartkops Estuary near Port Elizabeth,South Africa

Composition of alimentary canal contents (protein, ash, moisture and carbohydrate by difference) of four mullet species from the Swartkops Estuary, were determined monthly over a 13-month period. It was found that Liza tricuspidens consumed the most nutritious (highest protein and carbohydrate and lowest ash) material followed by Mugil cephalus, Liza richardsoni and lastly Liza dumerili, the most abundant mullet species in the estuary. It was also found that smaller specimens, irrespective of species, consumed the most nutritious food material. An attempt was made to relate chemical composition to the particular food and substrate preference of each species. Correlation coefficients between moisture and protein (positive), moisture and ash (negative) and ash and protein (negative) enabled the calculation of regression equations by which protein and ash can be determined from a relatively simple moisture determination.     

Distribution of juvenile mugilids in the hypersaline Bardawil Lagoon January 1973–January 1974

As part of a wider over-all investigation of the fishery dynamics, a study was made of the seasonal distribution of three size groups (≤30.00 mm, 30.1–60.0 mm and ≥ 60.1 mm total length) of juvenile mugilids at seven sampling stations in Bardawil Lagoon. For the whole period, all stations combined, 88 Mugil cephalus, 1 737 Liza ramada, 2 564 Liza aurata, 1 433 Liza saliens, 821 Chelon labrosus, 10 Liza carinata and one Oedalechilus labeo were taken by the sampling beach-seine. The results of this first year's collections of a two-year study are discussed.     

Stock enhancement in a commercial mullet,Mugil cephalus L., fishery in Hawaii

Abstract This study showed that cultured striped mullet, Mugil cephalus L., released as juveniles can make a significant contribution to landings in an island commercial fishery. Following pilot hatchery releases from 1990 to 1993, striped mullet fisheries in Kaneohe Bay, Hawaii, USA, were sampled to recover cultured fish from the bay-wide catch. Direct sampling of 181 fishing trips resulted in recovery of 211 cultured striped mullet. By autumn 1994, cultured fish comprised 13.0% (2.8%) of the commercial mullet catch in Kaneohe Bay, and the percentage was increasing logarithmically. This study corroborated predictions from previous studies of juveniles about effects of release strategies on survival of cultured mullet. Following summer releases, recapture rates were strongly affected by fish size-at-release, with a critical release size of 60 mm total length (the smallest size released that was subsequently detected in the fishery). Over 30 000 juveniles stocked in 1990 (but not in a nursery habitat preferred by striped mullet) apparently suffered complete mortality.     

Cloning and characterization of lipoprotein lipase (LPL) and the effects of dietary lipid levels on the expression of LPL in the redlip mullet (Liza haematocheila)

The genetic improvement of redlip mullet Liza haematocheila through breeding programmes is of interest for this important aquaculture species. Lipoprotein lipase (LPL) is a key enzyme in lipid deposition and metabolism. The purpose of this study was to investigate the nutritional regulation of LPL in redlip mullet. We cloned and identified the LPL gene, determined LPL gene expression in various tissues, and examined the effect of dietary lipid level on hepatic LPL gene expression. The LPL gene of redlip mullet Liza haematocheila (L.hLPL) was 2,395 bp in length and encoded 516 amino acids. Sequence analysis showed that L.hLPL shared 61%–90.3% identity with LPLs in other species. Expression patterns of hepatic L.hLPL were studied in redlip mullet fed diets containing 2.0, 4.8, 7.5, 9.8, 12.0 or 14.6 g/kg, crude fat for 60 days by real‐time quantitative PCR. The abundance of LPL mRNA in hepatic tissue increased with the increase in dietary fat. The expression L.hLPL mRNA was significantly higher in the groups fed diets with 14.6 and 12.0 g/kg fat than in the other groups (p < .05). Gene expression was significantly higher in the abdominal fat of redlip mullet (p < .05) compared with other tissues. In conclusion, a high fat diet (9.79–14.59 g/kg) induces L.hLPL expression in abdominal fat.     

Genetic identification and phylogenetic inferences in different Mugilidae species using 5S rDNA markers

A DNA methodology was developed to discriminate fry of six Mugilidae species found in the Mediterranean, namely Mugil cephalus, Mugil so‐iuy, Chelon labrosus, Liza aurata, Liza ramada and Liza saliens. Polymerase chain reaction (PCR) amplification of the 5S rDNA gene was used for the identification of the above six species. PCR products of two species showed different patterns on EtBr‐stained agarose gels; M. so‐iuy gave a pattern of three bands, while L. saliens gave a pattern of one band. Mugil cephalus, C. labrosus, L. aurata and L. ramada gave a pattern of two bands. Subsequent sequencing analyses revealed unique haplotypes for each of the remaining four species. This is a genetic technique that could be applied in hatcheries, for identification of fry mullet's species. Furthermore, 5S rDNA sequences of each of five of the studied species (i.e. M. cephalus, C. labrosus, L. aurata, L. ramada and L. saliens), as well as a sequence of Oedalechilus labeo that belongs to the Mugilidae family, were aligned and used for the examination of the phylogenetic relationships among them. Phylogenetic trees produced in our study are in general agreement with those presented in the literature. This is the first study to use a nuclear marker to elucidate the phylogeny of Mugilidae species.     

The identification of grey mullet species by disc electrophoresis

Electrophoresis was carried out on the water-soluble muscle protein (myogen) of six grey mullets (Mugilidae), caught off the Mediterranean coast of Israel. With the obtained electropherograms it was possible to identify the adults and juveniles of five species of grey mullet. A tentative key for species determination based on the myogen electrophoretic pattern of five species (Liza ramada (Risso, 1826), L. aurata (Risso, 1810), L. provensalis (Risso, 1826), L. saliens (Risso, 1810) and Mugil cephalus (Linnaeus, 1758)) is given. Of the sixth species, Oedalechilus labeo (Cuvier, 1829), only one small adult and six juvenile specimens were obtained.A fast moving band occurred in the pattern of all juveniles of the investigated species. This fraction decreased during growth of all species, it became faint in adults of L. saliens, L. provensalis and L. ramada and was not observed in adult L. aurata and M. cephalus.     

Characterization of β-haemolytic Group B Streptococcus agalactiae in cultured seabream, Sparus auratus L., and wild mullet, Liza klunzingeri (Day), in Kuwait

Streptococcus agalactiae was isolated from cultured gilthead seabream, Sparus auratus L., and diseased wild Klunzinger's mullet, Liza klunzingeri (Day), in Kuwait Bay, Arabian Gulf. Isolates were catalase negative, β‐haemolytic, Gram‐positive cocci and serogroup B. Experimental infectivity trials with mullet and seabream brain isolates in Nile tilapia, Oreochromis niloticus L., caused 100 and 90% mortality, respectively, within 7 days post‐inoculation indicating virulent S. agalactiae as the bacterial pathogen responsible for the epizootic in Kuwait Bay.     

Histopathological and behaviour effects of formaldehyde treatment in juvenile mullet,Mugil liza (Valenciennes)

Considerable losses may be related to diseases caused by parasites in aquaculture. Formaldehyde (37% gas dissolved in water) is an effective chemotherapeutic, widely used to control ectoparasites in fish. However, for many species of fish used in aquaculture, the control of external parasites and the deleterious effects of formaldehyde in short‐term baths are still uncertain. In order to clarify some gaps, 1 h‐prophylactic baths (67.5, 135, 270, 405 and 540 mg L^?1 formaldehyde in triplicate) were performed in juvenile mullet, Mugil liza (Valenciennes). Results showed that prophylactic baths of 135 mg L^?1 formaldehyde by 1 h did not cause death in tested mullets. At this concentration, histopathologies were mild and fish survival was high. However, fish exposed to increasing concentrations of formaldehyde presented severe histopathologies in the gills besides behavioural and morphological alterations. The histopathological and behavioural implications of formaldehyde use in aquaculture are discussed.