三种不同游泳习性鱼类骨骼肌的快、慢肌纤维组织学特性

硬骨鱼类的骨骼肌可为其游泳运动提供动力。为认识不同游泳习性鱼类的骨骼肌肌纤维组织学特征,本研究选取3种具有不同游泳习性的鱼类：鲐(Scomber japonicus)、大黄鱼(Larimichthys crocea)和褐牙鲆(Paralichthys olivaceus),采用石蜡切片苏木精–伊红染色法和形态计量法,以形状、直径和密度作为评价指标,对其骨骼肌的快、慢肌纤维组织学特性进行表征,比较3种不同游泳习性鱼类的快、慢肌纤维组织学特征差异。组织学观察发现,3种类型鱼类的骨骼肌快、慢肌纤维横切面均呈不规则形状。营持续式游泳的鲐的快肌纤维呈多角状,慢肌纤维呈多边柱形;营延长式游泳的大黄鱼的快、慢肌纤维呈长椭圆形;营爆发式游泳的褐牙鲆的快、慢肌纤维呈扁椭圆形。形态计量结果显示,3种鱼类的快肌纤维直径均极显著大于其慢肌纤维(P<0.01)。大黄鱼的慢肌纤维直径在3种鱼类中最大,约为鲐的1.34倍、褐牙鲆的1.14倍;鲐的快肌纤维直径在3种鱼类中最大,约为大黄鱼的1.41倍、褐牙鲆的1.35倍。3种鱼类的快肌纤维密度均极显著小于其慢肌纤维(P< 0.01),其中,快肌纤维密度大小排序为褐牙鲆[(274.60±9.07)根/mm2]>大黄鱼[(205.43±12.63)根/mm2]>鲐[(118.92±10.74)根/mm2],慢肌纤维密度大小排序为鲐[(1 442.33±28.25)根/mm2]>褐牙鲆[(1 073.92±39.40)根/mm2]>大黄鱼[(945.74±19.53)根/mm2]。进一步分析发现,鱼类的肌纤维形状、直径和密度与鱼类的游泳习性密切相关。上述对不同游泳习性硬骨鱼类骨骼肌的肌纤维形状、直径和密度等组织学特征的描述与差异分析结果,可为进一步开展硬骨鱼骨骼肌的适应性进化和运动生理学研究提供基础性资料。     

温度和元素浓度对Sr在褐牙鲆仔稚鱼耳石中的沉积影响

科学认识鱼类耳石中微量元素沉积与主要水环境因子的关系是基于耳石微化学方法重新构建鱼类生活史及反演其环境履历的重要前提。本研究以环境与耳石中重要元素Sr为例，研究在不同水温(16℃、19℃和22℃)和不同元素浓度(1×、2×和3×Sr)下Sr在褐牙鲆(Paralichthys olivaceus)仔稚鱼耳石形成生长过程中(孵化后15~93 d)的沉积(Sr∶Ca比)特征。结果显示，在不同水温下，耳石中Sr∶Ca比随水体中Sr浓度的升高呈线性增长，而元素分配系数(DSr)随元素浓度的升高先降低然后趋于稳定。在不同Sr浓度下，耳石中Sr∶Ca比及DSr均随水温升高呈增长趋势，二者在22℃时的值均显著高于在其他水温时的值。耳石中Sr沉积能够表征褐牙鲆仔稚鱼所经历的水环境中Sr浓度和水温的变化，可作为元素指纹应用于褐牙鲆早期生活史的重建和环境履历的反演。     

4种养殖鱼类非特异性免疫能力的比较研究

对德国镜鲤、彭泽鲫、褐牙鲆和大菱鲆4种养殖鱼类的白细胞吞噬率和红细胞C3b受体花环率进行了测定和比较.结果表明,4种养殖鱼类的白细胞均具有吞噬能力且差异显著(P<0.05),白细胞吞噬率的大小顺序为:彭泽鲫>大菱鲆>褐牙鲆>德国镜鲤;同时,4种养殖鱼类的红细胞表面都存在C3b补体受体,均可形成花环且花环率差异显著(P<0.05),大小顺序为:彭泽鲫>德国镜鲤>大菱鲆>褐牙鲆.说明鱼类的非特异性免疫能力具有显著的种间差异性.     

褐牙鲆♀×大西洋牙鲆♂杂交育种研究

为探讨褐牙鲆和大西洋牙鲆杂交育种的可行性，通过繁殖调控使褐牙鲆和大西洋牙鲆同步性成熟，采取正反交试验，获得了褐牙鲆（♀）×大西洋牙鲆（♂）杂交F1代——花关牙鲆（Paralichthysolivaceus早×Pdentatus6）。花关牙鲆受精卵卵径平均1．01mm；孵化适宜温度15—21℃，盐度25～35，孵化率平均71．3％，初孵仔鱼全长2．5～2．7mm；仔鱼在16—20℃下36d后伏底变态，变态个体全长平均11mm，育成率32．5％；反交受精率和孵化率极低，未获得杂交后代。简述了其发育时序和形态特征，探讨温度、盐度对花关牙鲆胚胎和仔鱼发育的影响，比较亲本与杂交鱼早期生长特征，初步分析反交不成功的原因。     

褐牙鲆南移广西的养殖试验

褐牙鲆(Paralichthys olivaceus)属鲽形目,鲽亚目,鲆科,牙鲆属,俗称牙片、左口、比目鱼.褐牙鲆为近海暖温性底层鱼类,分布广泛,适应性强,生长迅速,肉质鲜美,深受消费者的喜爱,是名贵的海水增养殖品种之一.     

褐牙鲆♀×大西洋牙鲆♂杂交育种研究

为探讨褐牙鲆和大西洋牙鲆杂交育种的可行性,通过繁殖调控使褐牙鲆和大西洋牙鲆同步性成熟,采取正反交试验,获得了褐牙鲆(♀)×大西洋牙鲆(♂)杂交F1代——花美牙鲆(Paralichthys olivaceus♀×P.dentatus♂)。花美牙鲆受精卵卵径平均1.01mm;孵化适宜温度15～21℃,盐度25～35,孵化率平均71.3%,初孵仔鱼全长2.5～2.7mm;仔鱼在16～20℃下36d后伏底变态,变态个体全长平均11mm,育成率32.5%;反交受精率和孵化率极低,未获得杂交后代。简述了其发育时序和形态特征,探讨温度、盐度对花美牙鲆胚胎和仔鱼发育的影响,比较亲本与杂交鱼早期生长特征,初步分析反交不成功的原因。     

褐牙鲆(♀)×犬齿牙鲆(♂)杂交F1及其亲本肌肉营养成分分析与比较

褐牙鲆(Paralichthys olivaceus)为东亚地区重要的海水养殖鱼类,在中国、日本和韩国海水养殖业中占有重要的地位.目前,褐牙鲆经过连续多代缺乏选择的人工繁育和养殖,造成养殖群体种质发生退化,生长速度和抗逆性下降,极大制约了牙鲆养殖业发展.以选育生长迅速、抗逆性强、饵料转化率高的牙鲆类养殖新品种为目的,作者对褐牙鲆(♀)×犬齿牙鲆(Paralichthys dentatus)(♂)的杂交育种进行了研究.本实验对褐牙鲆(♀)×犬齿牙鲆(♂)杂交F1及其亲本肌肉营养成分进行测定.结果显示,杂交F1含水率显著低于双亲(P＜0.05),粗蛋白含量显著高于双亲(P＜0.05),粗脂肪含量介于二者之间;杂交F1的氨基酸总量、必需氨基酸、非必需氨基酸、半必需氨基酸与鲜味氨基酸总量都显著高于褐牙鲆与犬齿牙鲆(P＜0.05);脂肪酸含量方面,脂肪酸总量、不饱和脂肪酸总量3种鱼由高到低排列顺序为褐牙鲆、犬齿牙鲆、杂交F1,三者饱和脂肪酸总量差异不显著(P＜0.05).对3种鱼肌肉的营养品质进行了评价,杂交F1的必需氨基酸指数EAAI(90.30)明显高于褐牙鲆(77.75)与犬齿牙鲆(79.34),在蛋白质品质上表现出一定杂种优势.上述结果表明,杂交F1的肌肉具有蛋白和氨基酸含量较高、脂肪酸含量较低的特点.     

三种常用化学消毒剂对牙鲆仔稚鱼的急性毒性研究

选用3种化学消毒剂对牙鲆仔稚鱼进行急性毒性试验。结果表明,高锰酸钾对牙鲆仔鱼的24 hLC504、8 h LC50和安全浓度分别为1.678×10-6、1.382×10-6和0.281×10-6,对牙鲆稚鱼的24 h LC50、48 hLC50和安全浓度分别为2.555×10-6、1.789×10-6和0.263×10-6;甲醛对牙鲆仔鱼的24 h LC50、48 h LC50和安全浓度分别为25.821×10-6、10.671×10-6和0.547×10-6,对牙鲆稚鱼的24 h LC50、48 h LC50和安全浓度分别为33.959×10-6、17.046×10-6和1.288×10-6;聚维酮碘对牙鲆仔鱼的24 h LC50、48 h LC50和安全浓度分别为15.744×10-6、8.163×10-6和0.658×10-6,对牙鲆稚鱼的24 h LC504、8 h LC50和安全浓度分别为25.802×10-6、21.286×10-6和4.346×10-6。牙鲆仔稚鱼对3种化学消毒剂的敏感性依次为:高锰酸钾>甲醛>聚维酮碘,并且牙鲆仔鱼分别对3种消毒剂的敏感性均大于牙鲆稚鱼分别对3种消毒剂的敏感性。最后依据本试验结果,作者对牙鲆疾病防治中消毒剂的使用进行了探讨。     

鱼类黏液细胞研究进展

鱼体的黏液腺分布于其表皮层,黏液细胞分泌黏液保护机体免受伤害,是鱼体抵御病原微生物入侵的第一道防线。目前对于褐牙鲆(Paralichthys olivaceus)[1]、鲇鱼(Silurus asotus)[2]、花鲈(Lateolabrax maculatus)[3]、剑尾鱼(Xiphophorus maculatus)[4]、大鳞副泥鳅(Paramisgurnus dabryanus)[5]、黄颡鱼(Pelteobagrus fulvidraco)[6]、点带石斑鱼(Epinephelus malabaricus)[7]、鲤鱼(Cyrinus carpio)[8]等鱼类黏液细胞已有相关的研究报道。笔者总结了鱼类黏液细胞的研究进展,以期为更深入研究其结构和功能奠定基础,对鱼类养殖以及疾病预防产生重要的实践意义。     

褐牙鲆(♀)×犬齿牙鲆(♂)杂交子代及亲本群体形态和外周血红细胞DNA含量

2006～2007年进行了犬齿牙鲆Paralichthys dentatus(♂)×褐牙鲆P.olivaceus(♀)杂交,获得杂交子代苗种养殖至全长27～33cm时随机取样,测定形态学特征。与父、母本相同规格成鱼相比,杂交子代的有眼侧体色和花纹与父、母本都存在较大差异,是区分杂交子代最突出的特征。杂交子代的多数可比、可量性状同父、母本相近,但在体长/总高比等方面表现出较明显的杂交优势。聚类分析表明,杂交子代的表型与犬齿牙鲆更为接近。尾静脉采血,使用流式细胞仪检测杂交子代和父、母本外周血红细胞的DNA含量,发现杂交子代、犬齿牙鲆和褐牙鲆的DNA含量分别为1.51±0.02、1.50±0.04、1.43±0.16pg,杂交子代的DNA含量与犬齿牙鲆接近,较褐牙鲆略高,表明杂交子代为二倍体。     

拖网渔船船-机-桨-网匹配研究

在拖网渔船的设计中,需要重点考虑螺旋桨与船-机的匹配、渔具与船-机-桨的匹配,实现推进系统的高效能发挥。本文引入时间概率的最佳螺旋桨参数优化确定方法,考虑拖网渔船设计的限制条件,通过优化分析,达到运营工况综合效能最佳,实现螺旋桨与船-机的合理匹配。从拖网渔船数据库中选取30艘运营状况优良的渔船进行有效拖力计算,建立拖网渔船有效拖力与主机功率和拖速的多元非线性回归方程,依据此方程得出的有效拖力结果选择网具和网板,实现有效拖力与渔具的合理匹配,最终实现渔具与船-机-桨的合理匹配。通过实船计算对比,验证了回归的有效拖力估算公式误差范围和适用性。研究表明:在拖网渔船设计初期,可以利用该公式估算有效拖力进行网具和网板的匹配,实现技术经济优化论证,最终实现船-机-桨-网的优化匹配。     

中型单拖网渔船拖力与渔具系统匹配的研究

中国有数十艘中型单拖渔船在大西洋中东部海域捕鱼，但对渔船拖力与网具，网板之间的匹配研究较少。作者经对三种不同型号渔船的测试，并同外国同类作业渔船进行对比分析，提出了网具，网板和纲索三者阻力的合理分配比例。同时提出确定渔具系统总阻力的方法。     

高分子编结网片水动力特性水槽试验研究

高分子渔用材料在设施养殖和海洋渔业中的应用越来越广泛,对其水动力特性进行研究十分必要。试验采用不同网目系数和网线粗度的高分子编结试验网片进行水槽试验,倾角从0°变化到90°,设置水流速度从0.3 m/s开始,以0.1 m/s为梯度,逐渐增大至1.3 m/s。为减小尾流和湍流对试验结果的影响,使用流线型框架固定装配。经试验得到以下结果:(1)在网片与水流垂直时,阻力系数有随网目系数增大而增大的趋势,而在网片与水流平行时,阻力系数随网目系数增大而减小。(2)阻力系数有随雷诺数增大而逐渐减少的趋势,网片平面与流体运动方向速度垂直时,阻力系数在13001500后阻力系数变化不大。(3)阻力系数随着冲角的增大而增大并最终趋于稳定值。(4)升阻力系数比(K)在总体上有随倾角变大而先变大再变小的趋势,K的极值均出现在20°到30°内,最大K值约为0.41。(5)网片与水流垂直时,在1000相似文献   

Fundamental studies on the hydrodynamic resistance of small pot traps

ABSTRACT:   The hydrodynamic resistance of small pot traps has been conducted in order to establish some basic information. The specific objectives of the study was to measure the hydrodynamic force and estimate the critical setting condition for traps. Five types of traps with different materials were used in the experiment: a netted semi-cylinder shape, a wire semi-cylinder shape, a heart shape, a box shape, and a cylinder shape. The hydrodynamic force of each trap was measured in a flume tank. Flow speeds in the flume tank were 0.1, 0.2, 0.3, 0.4, and 0.5 m/s. Attack angles for this study were 0, 15, 30, 45, 60, 75, and 90 degrees. At an attack angle of 0 degrees the main axis of the trap was parallel to the water flow and at 90 degrees it was vertical. The values of the hydrodynamic drag coefficient varied with traps: netted semi-cylinder shape, 2.75–5.96; wire semi-cylinder shape, 2.81–4.49; heart shape, 2.77–3.66; box shape, 2.39–2.97; and for cylinder shape, 3.57–3.67. The flow speed (0.5 m/s) was effective to set the netted semi-cylinder, wire semi-cylinder, box, and cylinder shaped traps. The same flow speed applied to the heart-shaped trap was only effective to a maximum of 30 degrees attack angles and below.     

Comparing and modifying penaeid beam and otter trawls to improve ecological efficiencies

In an attempt to improve the selectivity and engineering performances of generic penaeid trawls, three established and one novel spreading‐mechanism configurations were assessed: otter boards attached (1) with and (2) without 3.15‐m sweeps to a 7.35‐m headline trawl, and a beam rigged directly to a 9.19‐m trawl (3) with and (4) without a horizontal wire and plastic streamers. Despite more surface area (7.5 vs 6.0 m²), both beam‐trawl configurations had significantly lower drag than the otter trawls (≤30%). When catches were standardised to per ha, the otter trawl with sweeps retained significantly more (1.3–2.4 times) school prawns, Metapenaeus macleayi (Haswell), than the other three configurations. Within systems, removing sweeps or adding a horizontal wire significantly reduced the unwanted catches of a key teleost (southern herring, Herklotsichthys castelnaui Ogilby) by 41 and 48%. The results illustrate the utility of simple anterior modifications for independently addressing penaeid‐trawling environmental issues.     

Effects of drag coefficient of netting for dynamic similarity on model testing of trawl nets

SUMMARY: For design or improvement of fishing nets, a model test based on Tauti's law or Froude's law is well executed. However, because these modeling rules are based on the proportion of the drag of the net to the square of water velocity, the converted drag of the net from the result of model testing is considerably large compared with the observed value. In this study, Tauti's law and Froude's law were corrected considering the drag coefficient of the net to the Reynolds number based on the twine diameter used experimentally. Three different scale models: 1/12, 1/20 and 1/50 of a midwater trawl net of 61 m in total length were made according to the modified Tauti's law and Froude's law, and the full-scale and model experiment were carried out. Consequently, the difference between the converted drags of full-scale by three scale models and measured values was within 10%. Each of these modified modeling rules is effective for the model test of trawl nets.     

Fluid dynamic resistance for the trolling depressor

ABSTRACT: The mechanism of deciding a posture of the trolling depressor in the towing was investigated. The hydrodynamic characteristics of the trolling depressor, which has been widely used by Japanese coastal fishermen, were investigated using models with a 394.5 cm² plane form area in different shapes and cambers. These models were rigged for an attack angle from −10° to 90°. The lift, drag and moment were measured by a three-component load cell in the circulating water tank. The difference in the shape of the trolling depressor did not affect the drag coefficient. Superior efficiency of the trolling depressor is considered to be due to the effect of camber. The position of the pressure center very near the front edge makes the trolling depressor move downward. Disagreement of points between the towing point and the pressure center accelerated the swinging movement of the trolling depressor.     

Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean

The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.     

Growth performance,digestive enzyme activity and immune response of Japanese sea bass,Lateolabrax japonicus fed with fructooligosaccharide

In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.     

Involvement of gonadal steroids in final oocyte maturation of white perch (Morone americana) and white bass (M. chrysops): in vivo and in vitro studies

Plasma estradiol-17 (E₂), testosterone (T), 17,20-dihydroxy-4-pregnen-3-one (DHP) and 17,20,21-tri-hydroxy-4-pregnen-3-one (20-S) levels were measured by radioimmunoassay (RIA) in white perch (Morone americana) and white bass (M. chrysops) that were induced to undergo final oocyte maturation (FOM) with human chorionic gonadotropin (hCG). Plasma DHP levels increased in females of both species in association with oocyte germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) and decreased thereafter. Plasma 20-S levels also increased with oocyte GVM in white bass, but were several-fold lower than DHP levels. Circulating E₂ and T levels were greatest during GVM and GVBD in both species and decreased to low levels during oocyte hydration and ovulation. Follicles from white perch and white bass which received a priming injection of hCG in vivo, produced both DHP and 20-S in vitro after exposure to hCG and their oocytes underwent GVBD. Ovarian incubates from unprimed fish of either species produced only E₂ and T and their oocytes did not complete GVBD. Oocytes from unprimed bass, but not perch, matured when follicles were exposed to hCG in vitro. Both trilostane and cycloheximide blocked in vitro production of DHP and 20-S and oocyte GVBD by white perch follices. DHP and 20-S were equipotent inducers of FOM in the GVBD bioassay. None of several other structurally-related steroids tested were effective within a physiological range of concentrations. These results indicate a role for DHP and 20-S in the control of FOM in white perch and white bass.