基于耳石形态特征的南海鸢乌贼群体判别分析

【目的】通过耳石形态参数对南海鸢乌贼(Sthenoeuthisoualaniensis)不同群体进行判别。【方法】采用2012年4月-2013年1月采自南海南沙群岛、东沙群岛和中沙西沙群岛周边海域灯光罩网渔获的268尾鸢乌贼耳石样本(雌性166尾、雄性102尾),通过耳石总长(TSL)、最大宽度(MW)、侧区长(LDL)、背侧区长(DLL)、吻侧区长(RLL)、吻区长(RL)、吻区宽(RW)、翼区长(WL)和翼区宽(WW)9个形态参数进行主成分分析,采用不同校正方法判别分析3个不同海域和3个不同体型群体的耳石差异性。【结果】统计并分析鸢乌贼耳石形态参数可知,南海鸢乌贼耳石具有翼区宽大、侧区次之、背区稍小、吻区长窄的形态特征。主成分分析表明,鸢乌贼的耳石长度参数TSL、LDL、DLL、WL和宽度参数MW可代替9项形态参数来描述耳石的形态特征;函数拟合结果,5项表征与鸢乌贼胴长有较强的线性函数关系。判别分析表明,比值校正法对3个地理群体判别中具有较好稳定性,总体成功率为60.4%;中沙西沙群体和微型群体的耳石形态在判别中有较好的区分度。【结论】不同群体的南海鸢乌贼耳石形态特征具有较大差异性,中、西沙群体和微型群体与其他群体存在较高的区分度。     

南海北部海域中国枪乌贼耳石的形态学分析

2015年在南海北部海域采集中国枪乌贼样本102尾,测定个体以及耳石形态学参数,利用主成分分析法获得中国枪乌贼耳石主要形态特征参数,分析耳石特征参数与胴长(ML)、性成熟等的关系,建立主要形态参数与胴长和体质量的关系模型。结果表明,长度参数耳石总长(TSL)、吻区游离端长(RL)和宽度参数最大宽度(MW)、翼区宽(WW)可代表中国枪乌贼耳石的形态特征;TSL、RL与ML之间以线性模型为最佳,WW、MW与ML之间以幂函数模型为最佳;TSL、RL、WW、MW与体质量之间以线性模型为最适;性成熟对耳石形态参数特征MW/TSL影响无统计学意义(P0.05)。     

东太平洋赤道公海茎柔鱼生物学特性

根据2013年4~6月在赤道公海探捕期间采集茎柔鱼样本,研究赤道公海茎柔鱼渔业生物学特性。结果表明,不同性别、不同月份,茎柔鱼胴长和体质量组成不同。雌、雄性样本的胴长范围分别为93~495 mm和94~406 mm,优势胴长组分别为260~340 mm和240~320 mm,分别占样本总数72.53%和70.26%;雌、雄性样本体质量范围分别为25~3 900 g和33~2170 g,优势体质量组分别为400~1 200 g和200~1 000 g,分别占样本总数82.71%和87.82%。雌、雄性茎柔鱼净体质量比例分别介于31.69%~80.51%和37.05%~81.35%之间,平均值分别为60.45%和62.73%。协方差分析表明,茎柔鱼胴长与体质量、胴长与净体质量的生长均存在性别间差异,胴长与体质量的生长都最适合用幂函数表示,而胴长与净体质量的生长,雌、雄性样本分别最适合用幂函数和指数函数表示。不同月份茎柔鱼性别比例构成不同,4月、5月和6月性别比例分别为1.87∶1、1.61∶1和1.17∶1,全部样本的性别比例为1.61∶1。不同月份茎柔鱼性腺成熟度的组成不同。不同性别、不同月份间茎柔鱼胃含物等级组成存在差异。     

池养条件下军曹鱼早期发育阶段的生长和摄食

研究了军曹鱼(Rachycentron canadum)早期阶段的生长和摄食特性。结果表明:1~29日龄间,全长与日龄之间呈指数函数相关:y=3.6922e0.0995x(R=0.9913);体重与日龄间呈指数函数相关:y=0.0002e0.276x(R=0.9830);体重与全长之间为幂函数相关:y=5×10-6x2.786(R=0.9957);口径与日龄的关系为直线函数关系:y=0.1034x-0.0044(R=0.9939)。鱼苗早期阶段的生长速度存在显著性差异。军曹鱼早期鱼苗在3~6日龄时主要摄食原生动物、单轮幼虫和轮虫;7~12日龄时主要摄食桡足类无节幼体;13日龄以后主要摄食桡足类成体。仔、稚鱼阶段,军曹鱼的摄食活动呈现明显的昼夜节律,其饱满度指数均在12时前后出现最高峰,日摄食率分别为57.36%和14.78%。     

网箱养殖唇鱼骨的生长性能与生长模型

研究网箱养殖1、2、3龄唇鱼骨的生长性能,并结合唇鱼骨生长数据,应用Logistic、Gompertz和von Bertalanffy生长模型拟合其生长曲线。结果表明:1、2、3龄唇鱼骨的特定生长率随年龄的增长而逐渐下降,1龄鱼特定生长率最高,为4.56%/d,其次为2龄鱼,为2.05%/d,3龄鱼最低,为0.93%/d;随年龄的增长,唇鱼骨的肥满度也逐渐增加,1、2和3龄鱼肥满度依次为0.015、0.016、0.018 g/cm3;1和2龄鱼饵料系数相近,分别为1.44和1.31,均低于3龄鱼饵料系数1.88;不同月龄唇鱼骨的体质量和体长均随月龄的增加而呈指数函数增长。3种生长方程拟合结果表明,von Bertalanffy生长模型的拟合度最高,可较好表达网箱养殖唇鱼骨的生长过程及变化规律。     

鱼类的性别决定和分化及其研究方法综述

鱼类在性别决定机制上是极其多样的,大多数鱼雌雄异体,还有雌雄同体鱼,有些鱼能自然发生性逆转(如黄鳝等),有些能发生天然的雌核发育(如银鲫).鱼类性别的可塑性也很强,可以通过激素进行性转.有些鱼类的生长特性与性别有着很大的关系,如雄性罗非鱼的生长速度就比雌性快,雌性鲤鱼、草鱼的生长比雄性快,通过养殖单性鱼可以大幅度提高养殖产量.因此需要对鱼类性别决定和分化的机制进行广泛和深入的研究,这样不仅可以通过性别分化来研究动物的进化过程,而且可以利用性别差异来改善鱼类的养殖情况.     

鱼类的性别决定和分化及其研究方法综述

鱼类在性别决定机制上是极其多样的，大多数鱼雌雄异体，还有雌雄同体鱼，有些鱼能自然发生性逆转(如黄鳝等)，有些能发生天然的雌核发育(如银鲫)。鱼类性别的可塑性也很强，可以通过激素进行性转。有些鱼类的生长特性与性别有着很大的关系，如雄性罗非鱼的生长速度就比雌性快，雌性鲤鱼、草鱼的生长比雄性快，     

军曹鱼仔鱼期的摄食与生长

以人工孵化的军曹鱼(Rachycentron canadum)卵黄囊期仔鱼为材料,对仔鱼早期阶段的摄食及生长情况进行研究。结果表明:在水温28~32℃条件下,军曹鱼仔鱼3日龄开始摄食,6日龄时卵黄完全耗尽,6~7日龄饥饿仔鱼进入不可逆点(PNR)期;混合营养期3~4 d。饥饿仔鱼的初次摄食率开始较低,此后上升,到卵黄囊快要耗尽时达高峰(50%),以后又下降。内营养期,仔鱼日平均生长率为0.86 mm/d;PNR前的摄食期,饥饿仔鱼的日平均增长率为0.068 mm/d,而摄食仔鱼的日平均生长率为0.64 mm/d;PNR后至死亡前,饥饿仔鱼体长呈负增长,而摄食仔鱼的日平均生长率达1.04 mm/d。摄食仔鱼在孵化后8 d内的全长和日龄呈指数关系;前10 d的口径与全长呈正比关系。     

黑脊倒刺鲃仔稚鱼摄食的习性与生长

研究了养殖条件下黑脊倒刺仔稚鱼摄食习性与生长,结果表明:仔鱼4日龄开口摄食,全长9.0~9.99mm;仔稚鱼的摄食具有明显的昼夜节律性;仔稚鱼个体间生长速度具有一定的差异性;其体重与摄食量的关系为y=0.064 4X+1.433 1,全长与日龄的关系为L=8.861 4×exp(0.042 9T),体重与日龄的关系为W=3.736×exp(0.151 3T),全长与体重的关系为W=1.7×10-3×L3.531 4。     

菊黄东方鲀1龄幼鱼生长特性

对600尾菊黄东方鲀(Takifugu flavidus)1龄幼鱼在池塘养殖条件下的生长特性进行研究。结果表明:菊黄东方鲀67日龄幼鱼经过127 d的培育后,体长从(3.53±0.73)cm增至(10.33±0.98)cm,日均增长0.054 cm,体长增长率193.14%;体质量从(2.41±1.60)g增至(54.39±13.62)g,日均增重0.413 g,体质量增长率2 135.8%,体质量与体长呈幂函数关系,关系式为:W=0.044 8 L3.057 0(R2=0.9922),b值接近于3,属等速生长型。体长(l)与日龄(t)表现为线性相关:l=0.058 5 t+3.781 1(R2=0.9621),体质量(w)与日龄(t)表现为指数相关:w=3.3211 e0.028 6t(R2=0.9363)。     

Impacts of El Ni?o on the somatic condition of Humboldt squid based on the beak morphology

The Humboldt squid Dosidicus gigas has a short life span,and environmental variability plays a significant role in regulating its population dynamics and distribution.An analysis of 1 096 samples of D.gigas collected by the Chinese commercial fishing vessels during 2013,2014,and 2016 off the Peruvian Exclusive Economic Zone,was conducted to evaluate the impacts of El Ni?o events on the somatic condition of D.gigas.This study indicates that the slopes of all beak variables in relation to mantle length(ML)for females were greater than those of males during 2013,2014,and 2016,and slopes of the upper crest length and the lower ro strum length significantly differed between females and males in 2013(P0.05).Variation in the slopes for beak variables among years was studied;no significant difference was observed(ANCOVA,P0.05).The Fulton's condition coefficients(K)of females and males in 2013 and 2014 were significantly greater than tho se in 2016(P0.01).01).The K values of females were greater than tho se of males in 201 3,2014,and 2016,and K values significantly differed between females and males in 201 3.In normal years,the chlorophyll a(Chl a)concentration showed an N-shaped variability from January to December.However,in the El Ni?o period,it tended to weaken the upwelling coupled with warm and low Chl a concentration waters.We suggest that the poor somatic condition of D.gigas during the El Ni?o year was resulted from the low Chl a concentration in the waters,and the abundance of D.gigas would decrease due to the unfavourable environment and the lack of prey items in the El Ni?o year.     

Estimation of age,growth and maturation of purpleback flying squid, <Emphasis Type="Italic">Sthenoteuthis oualaniensis</Emphasis>, in Bashi Channel,central Pacific Ocean

The age, growth and maturation of Sthenoteuthis oualaniensis were determined with statolith data collected with a light purse seine from the Bashi Channel of central Pacific Ocean. The estimated longevity of the squid was no more than 6 months for females, and no more than 5 months for males. Growth in mantle length (ML) was best described by logistic models for both females and males, while growth in body weight (BW) was best fitted by power curves. The maximum absolute growth rate (AGR) and instantaneous growth rate (IGR) in ML or BW both occurred at 91–105 days for females and 76–90 days for males. Back calculated hatching dates were from October to January, with a peak in December, although the short duration of sampling date might have had an influence on the result. The lower percentage of mature females (37.2%) suggested that the study area during the sampling date was not a spawning ground for the species. Size and age at first maturity were 183 mm ML and 136 days for females, whereas they were 156 mm ML and 85 days for males.     

Using statolith shape analysis to identify five commercial Loliginidae squid species in Chinese waters

Identification of squids in the family Loliginidae is a time-consuming exercise because of the highly overlapping distributions of species and their overall similarity(fin shape and size, sucker ring dentition, and color). Identifying squid based on statolith morphology is considered more accurate than identifying species based on beaks or gladius morphology. We report and compare the statolith shape offive commercially Loliginidae squid( Uroteuthis( Photololigo) duvaucelii, U. edulis, U. chinensis, Loliolus beka, L. japonica) to determine how well these structures discriminate species. Based on statolith morphology, variation in the lateral and dorsal domes enables an 84.8% success rate at classifying species. Environmental factors correlate with statolith shape, and for vertically migrating squid, statolith relative size decreases with increased depth of habitation. Statolith morphology can be used to effectively and accurately identify species of Loliginidae squid occurring in Chinese waters, and may prove valuable for identifying and managing squid resources.     

Molecular Identification of Dried Shellfish Products Sold on the Market Using DNA Barcoding

The dried shellfish products with rich nutrients and low-calorie content are favorite food in China, especially in coastal areas. However, the species of dried shellfish products in the market are usually unknown, as the taxonomic features were removed during the production process. This study described the application of DNA barcoding technique to the identification of 100 dried shellfish(scallop, squid, octopus and cuttlefish) products in markets. Samples were authenticated by comparing mitochondrial cytochrome oxidase subunit I(COI) gene and 16 S ribosomal RNA(16 S rRNA) gene sequences with public reference taxonomic databases. The results showed that all the 100 products can be identified at species level. Sixty four scallop adductor products were processed using the bay scallop, Argopecten irradians, and one was from Portuguese oyster, Crassostrea angulata. All the 27 squid, 2 cuttlefish and 6 octopus products were produced by the Jumbo flying squid, Dosidicus gigas. The neighbour-joining tree is in agreement with the results of DNA barcoding analysis. The 64 scallop samples formed one A. irradians cluster, leaving Sca65 clustered with the reference oyster sequence C. angulata(MH997922). All the 35 cephalopod(squid, octopus and cuttlefish) samples formed a D. gigas cluster. This investigation revealed a low variety of dried shellfish products sold on the market, and highlighted the high rate of mislabeling and species substitution. Our present work provides a practical method for tracing and authenticating shellfish products.     

智利外海茎柔鱼生物学特性的初步研究

根据2007年1月和5～6月我国鱿钓船在智利外海的调查数据,对茎柔鱼生物学特性进行初步分析。结果表明:该地区茎柔鱼胴长范围287～702 mm,优势胴长为380～430 mm,占64.2%;体重范围0.63～11.3 kg,优势体重为0.5～2.0 kg,占75.6%;调查海区渔获个体自西向东、自南往北呈现增大趋势;依据胴长组成推断调查海域可能存在3个群体。生长指数大于3,与秘鲁外海茎柔鱼相近;雌雄性比约为3:1,性腺成熟度以Ⅰ期为主,占92%;摄食等级0～2级为主,约占73%;当地时间00:00后摄食量增大,胃含物以鱿鱼和中上层小型鱼类为主。     

Identification of three common Loliginidae squid species in the South China Sea by analyzing hard tissues with geometric outline method

The hard tissues of squid can provide important information for species identification. In this study, we used statolith and beak to identify three squid species including Uroteuthis duvaucelii, Loliolus beka, and U. edulis in the South China Sea. Because of the highly overlapping habitat and similar body morphology of the three squid species, we explored four different ways to identify them, by using statolith, upper beak, lower beak and a combination of statolith and beak. An outline geometric morphometric method and stepwise discriminant analysis were used to evaluate the most suitable method for the identification. We found that the combination of statolith and beak had the highest cross validation rate that was 75.0%, 87.5% and 88.7% for U. duvaucelii, L. beka and U. edulis, respectively. Using two beaks had similar results and the lowest cross validation rate was 60.0%, 50.0%, and 73.7% for the upper beak, 46.9%, 58.5% and 75.3% for the lower beak of U. duvaucelii, L. beka and U. edulis, respectively. Analyzing with the statolith had moderate cross validation which was 72.2%, 80.0%, and 87.7% for U. duvaucelii, L. beka and U. edulis, respectively. From the results it is suggested when the entire body of a squid is available, a combination of statolith and beak should be used for the identification. When only one hard tissue is available, species identification can be subjected to large errors.     

3种柔鱼线粒体基因与核核糖体基因片段序列比较分析

为准确检测柔鱼（Ommαstrephesbartram川、茎柔鱼（ Dosidicus gigas）与阿根廷滑柔鱼（ IIIex argentinus ） 的种间遗传差异,对线粒体16SrRNA、细胞色素b（Cytb）与编码核糖体大亚基的基因（28SrDNA）片段序列进 行测定。经比对获得同源片段序列的长度分别为444、430、464坤,其中16SrRNA与28SrDNA基因片段上分别存在3处和47处碱基插入/缺失。核昔酸组成分析表明;3种柔鱼在3个基因片段上的核音酸组成差异不显著, 在线粒体2个基因片段上的A＋T含量（16SrRNA;69.90%、72.01%、74.66%; Cytb; 63.61%、68.91%、71.65% ） 均明显高于C＋C含量（16SrRNA;30.10%、27.99%、25.34%; Cytb; 36.39%、31.09%、28.35% ）,而在28SrDNA 基因片段上的A＋T含量（37.16%、36.74%、38.29% ）明显低于C＋C含量（62.84%、63.26%、61.71 %）0 3种柔鱼 在28SrDNA基因片段上检测到的核昔酸替代率最低,为6.68%,而蛋白质编码基因Cytb核昔酸替代率最高,为 20.93%,核营酸替代均发生在密码子第3位点上,而且未引起氨基酸替代。基于邻接法、最大简约法与最大似然 法重建的系统树显示,柔鱼与茎柔鱼的亲缘关系较近。根据C严b基因片段序列分析,柔鱼与茎柔鱼和阿根廷滑柔鱼的分歧时间分别为653-790万a和765 - 925万a,种间分化事件发生在中新世至上新世间。     

A Preliminary Analysis of Trace-Elemental Signatures in Statoliths of Different Spawning Cohorts for Dosidicus gigas off EEZ Waters of Chile

We applied solution-based ICP-MS method to quantify the trace-elemental signatures in statoliths of jumbo flying squid, Dosidius gigas, which were collected from the waters off northern and central Chile during the scientific surveys carried out by Chinese squid jigging vessels in 2007 and 2008. The age and spawning date of the squid were back-calculated based on daily increments in statoliths. Eight elemental ratios(Sr/Ca, Ba/Ca, Mg/Ca, Mn/Ca, Na/Ca, Fe/Ca, Cu/Ca and Zn/Ca) were analyzed. It was found that Sr is the second most abundant element next to Ca, followed by Na, Fe, Mg, Zn, Cu, Ba and Mn. There was no significant relationship between element/Ca and sea surface temperature(SST) and sea surface salinity(SSS), although weak negative or positive tendency was found. MANOVA analysis showed that multivariate elemental signatures did not differ among the cohorts spawned in spring, autumn and winter, and no significant difference was found between the northern and central sampling locations. Classification results showed that all individuals of each spawned cohorts were correctly classified. This study demonstrates that the elemental signatures in D. gigas statoliths are potentially a useful tool to improve our understanding of its population structure and habitat environment.     

Age, maturation, and population structure of the Humboldt squid Dosidicus gigas off the Peruvian Exclusive Economic Zones

Age, maturation and population structure of the Humboldt squid Dosidicus gigas were studied based on random sampling of the Chinese jigging fishery off the Peruvian Exclusive Economic Zones (EEZ) during 2008–2010. Estimated ages ranged from 144 to 633 days, confirming that the squid is a short-lived species with longevity no longer than 2 years. Occurrence of mature females and hatching in each month indicated that Humboldt squid spawned year-round. Back-calculated hatching dates for the samples were from January 22^nd, 2008 to April 22^nd, 2010 with a peak between January and March. Two size-based and two hatching date-based populations could be defined from mantle length (ML) at maturity and back-calculated hatching dates, respectively. Females matured at a larger size than males, and there was a significant difference in ML at maturity between the two hatching groups (P <0.05). The waters adjacent to 11°S off the Peruvian EEZ may be a potential spawning ground. This study shows the complexity of the population structure and large variability in key life history parameters in the Humboldt squid off the Peruvian EEZ, which should be considered in the assessment and management of this important resource.