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1.
利用2012年3月-2013年2月在鄱阳湖通江水道进行的定置网渔获物调查的数据,运用软件FiSAT II对翘嘴鲌(Culter alburnus)的生长参数以及种群补充模式进行了估算。结果显示,鄱阳湖通江水道翘嘴鲌体长范围为93-645 mm;体长(L, mm)和体重(W, g)的关系式为W = 0.9×10-5L3.029 (R2=0.975, n = 317),von Bertalanffy生长方程的各参数：渐近体长L∞= 677.25 mm,生长系数K= 0.140,理论生长起点年龄t0 = -0.854。总死亡系数Z=1.514/a,自然死亡系数M=0.173/a,捕捞死亡系数F = 1.341/a。鄱阳湖通江水道翘嘴鲌开发率E=0.886,资源处于过度利用状态。种群补充模式表明,鄱阳湖通江水道翘嘴鲌种群补充期在4–8月。因此,建议适当延长鄱阳湖的禁渔期,以利于其资源的恢复与保护。  相似文献   

2.
鄱阳湖刀鲚繁殖群体生物学参数及生长特性的初步分析   总被引：1，自引：0，他引：1  
基于渔业资源调查数据,运用软件FiSATⅡ分析了鄱阳湖刀鲚繁殖群体的生物学参数及生长特性。分析结果表明,鄱阳湖刀鲚体长16.0~38.1cm;体长和体质量的关系式为m=0.002L3.139(r=0.949;P0.05;n=1014),von Bertalanffy生长方程的各参数为:渐近体长为40.95cm,生长系数为0.240,理论生长起点年龄t0=-0.568。鄱阳湖刀鲚的拐点体质量为67.94g,平均丰满度为0.29±0.04(0.14~0.49),总死亡系数为1.36a-1,自然死亡系数为0.52a-1,捕捞死亡系数为0.84a-1。鄱阳湖刀鲚开发率为0.61,处于资源过度利用状态。  相似文献   

3.
鄱阳湖刀鲚生殖群体特征及状况分析   总被引：1，自引：0，他引：1  
研究鄱阳湖刀鲚群体的生殖特征和条件状况,为制定开发利用渔业资源的政策提供基础资料,以实现鄱阳湖刀鲚资源的可持续开发和保护。2013、2014年4-7月,分别在鄱阳湖及湖口八里江段进行了实地渔业资源调查,随机抽样定置网、流刺网和拖网采集的鄱阳湖刀鲚样本共658尾,测量了体长、体重、净重、性腺重和性别。雌性287尾、雄性371尾,体长18.6~38.1 cm、体重16.3~198.2 g。雌性刀鲚的体长和体重均大于雄性(P0.01),雌、雄个体的体长和体重差异均为极显著(P0.01)。随着体长的增加,雌雄体重差异越大;同等体长的雌性体重大于雄性。6月中旬、下旬的刀鲚卵巢发育仍参差不齐,有些可挤出卵粒,已发育到Ⅳ期末和Ⅴ期,有些还处在Ⅳ期初,但成熟系数在2.0以下的个体数量已显著减少。绝对繁殖力为960~13 820粒,相对繁殖力为123.4~753粒/g。平均丰满度为0.30±0.03(0.19~0.45)。鄱阳湖刀鲚雌雄比在1∶1.25~1.44,表现出雄多雌少的现象;刀鲚繁殖种群已呈现出逐渐变小的趋势,资源已出现严重的过度利用。  相似文献   

4.
鄱阳湖鲤的年龄与生长特征   总被引：3，自引：0，他引：3  
为了解大型通江湖泊鄱阳湖中鲤(Cyprinus carpio Limaeus)的种群状况,根据2001年采集的448尾标本,对鲤的年龄和生长特征进行了研究.鄱阳湖鲤鳞片上的年轮表现为切割与疏密特征,尤以切割为主.渔获物群体平均体长为32.6 cm,平均体重为941.7 g,年龄结构为0+～4+龄,其中3+龄以下个体约占94.0%.鳞径(R)与体长(L)的关系为L=6.7963+29.421R(r=0.9128),体重(W)与体长(L)的关系为形=0.0219L3.0018(r=0.9979),拟合的Von Bertalanffy生长方程参数为L∞=97.26 cm,W=20315.39 g,k=0.2073,t0=-0.7841.与其它水域相比,鄱阳湖鲤生长较快,其生长拐点年龄为4.52龄,建议将其捕捞年龄确定在4.5龄左右.与20世纪70年代相比,鄱阳湖鲤表现出小型化趋势,应采取实施春季禁渔制度、控制捕捞强度、提高捕捞年龄、保护湖滩草洲生态环境等措施,实现渔业资源增殖.  相似文献   

5.
鄱阳湖刀鲚的渔汛特征及渔获物分析   总被引：2，自引：0，他引：2  
通过探究鄱阳湖刀鲚(Coilia ectenes)的渔汛特征和渔获物现状,为有效地保护其种群资源提供科学依据。2013-2014年在鄱阳湖设置3个调查点,对刀鲚进行逐月采样调查,共取样986尾、41.54 kg,随机抽样调查不同捕捞网具的整船次鄱阳湖刀鲚渔获物数据,测量体长、体重等生物学参数。采用Pearson相关分析刀鲚单船日渔获重量WB与水文因子关系。结果表明,鄱阳湖刀鲚体长范围为17.9~38.1 cm,其中21.2~23.6 cm是优势体长组,占总个体数的37.02%;体重范围为14.3~198.2 g,其中25~40 g是优势体重组,占总个体数的57.20%。鄱阳湖刀鲚体长L(cm)和体重W(g)幂函数方程为:W=0.0019L3.1378(R2=0.8997;n=986;P0.01)。湖口水域刀鲚出现时间主要集中在每年的5-6月,高峰期在6月,7月很少见;单船渔获数量NB为(3.2±4.1)尾/d,单船渔获重量WB为(0.12±0.11)kg/d。湖口水域刀鲚单船渔获重量WB与该水域水位、流量均呈显著正相关(P0.05),WB与水位的相关性更为显著。与历史资料相比,鄱阳湖刀鲚渔获规格以小个体居多;渔汛稍有推迟,持续时间大幅度缩短;种群规模急剧缩小,表明刀鲚资源正在严重衰退。  相似文献   

6.
2014年采集自湖北长湖的479尾短颌鲚(Coilia brachygnathus)样本,研究了长湖种群的年龄结构和生长特性。短颌鲚的耳石和鳞片均可用于鉴定短颌鲚年龄,且两者鉴定年龄的吻合度达到75.8%。长湖短颌鲚种群的年龄组成为1~4龄,其中1~3龄鱼为主,占总样本量的96.0%。短颌鲚属匀速生长型,其体重和体长的关系为:W=6.290×10-6L2.855(n=479,R2=0.959,P0.01),且无明显性别差异。长湖短颌鲚体长与体重的生长符合Von Bertalanffy生长方程:L_t=332.869[1-e-0.213(t+1.775)],W_t=99.940[1-e-0.213(t+1.775)]2.855,其生长拐点为t=3.15龄。为了可持续开发利用长湖短颌鲚渔业资源,建议捕捞规格提高到体长200 mm。  相似文献   

7.
鄱阳湖通江水道是多种洄游性鱼类完成生活史过程的重要通道, 具有重要的生态功能, 对于长江中下游鱼类资源的养护及其多样性维持至关重要。为了解越冬时期鄱阳湖通江水道中不同体长鱼类资源的空间分布规律及栖息生境状况, 本研究将鱼类声学探测、生境遥感定量制图分析和三维水动力模拟相结合, 分别绘制出 3 种不同体长鱼类群落的水深(SID)、流速(SIV)、坡度(SIS)等单因子生境适宜度指数曲线, 并利用乘积法建立栖息地适宜性指数(habitat suitability index, HSI)模型, 对通江水道中不同水域的鱼类生境适宜度进行对比和评估。结果表明, 鄱阳湖通江水道越冬时期鱼类平均全长为(10.1±5.73) cm, 主要分布在屏峰山以北的湖口县、鞋山和屏峰附近 3 个水域; 小体长鱼类群组(1~20 cm)水深的生境适宜度曲线为双峰型, 最适宜水深包括 3.06~4.59 m 和 9.18~12.24 m 两个区间, 流速为 0.05~0.13 m/s, 坡度为 0~2.23°; 中等体长组(20~40 cm)及大体长组(＞40 cm)鱼类适宜的水深、流速和坡度的生境适宜度曲线均为单峰型, 其中中等体长组最适宜栖息的生境因子范围为水深 9.18~13.77 m、流速 0.05~0.13 m/s 和坡度 0~2.23°, 大体长组为 13.77~15.3 m、0.10~0.13 m/s 和 0~2.23°。  相似文献   

8.
2018年6～10月在鄱阳湖湖区鄱阳、都昌、瑞洪及星子水域对397尾鲫鱼、575尾鲤鱼样本进行了生物学测定。在采集的样本中,鲫鱼最大体长25.5 cm,最大体重651 g;鲫鱼最小体长6.9 cm,最小体重12 g。鲤鱼最大体长为87 cm,最大体重18500 g;最小体长11.5 cm,最小体重31g。数据分析结果显示:鄱阳湖湖区鲤、鲫鱼体长体重关系为式为W_(鲤鱼)=2E-0.5L~(3.0445)(r=0.9951,n=575)、W_(鲫鱼)=2E-0.5L~(3.0383)(r=0.9939,n=397);在鄱阳湖湖区鱼类捕捞季节,鲤鱼、鲫鱼其捕捞规格分别以10～59.9 cm、10～14.9 cm为主,分别占70.25%和63.98%。  相似文献   

9.
研究基于鄱阳湖渔业资源调查数据,运用软件FiSAT II对翘嘴鳜的生物学参数及其资源量进行了初步估算。结果显示,鄱阳湖翘嘴鳜体长范围为77-526 mm;体长和体重的关系式为W = 1.888´10-5L3.042(R2=0.951, n=577),von Bertalanffy生长方程的各参数为: 渐进体长L∞ = 551.25 mm,生长系数K = 0.210,理论生长起点年龄t0 = -0.601。总死亡系数Z=1.06/a,自然死亡系数M=0.44/a,捕捞死亡系数F=0.62/a,最适开捕体长为150 mm。鄱阳湖翘嘴鳜开发率E = 0.58,处于资源过度利用状态。鄱阳湖翘嘴鳜的初始资源量估算高达1.92´104 t,最大可持续产量MSY为4384.93 t。鄱阳湖翘嘴鳜群体中补充群体和低龄剩余群体的比例明显增加,低龄化和小型化趋势凸显,资源衰退问题突出,但生长潜力依然存在。应采取降低对鄱阳湖翘嘴鳜繁殖群体的捕捞强度、保护产卵场等积极措施来保护这一珍贵的渔业资源。  相似文献   

10.
鄱阳湖鲫的年龄与生长特征   总被引：1，自引：0，他引：1  
以鳞片作为年龄鉴定材料,对鄱阳湖鲫的年龄结构以及生长特性进行了研究。结果显示:鄱阳湖鲫种群由5个年龄组(1a～5a)构成。体重(W,g)与体长(L,mm)的关系式为:W=5*10-5L2.887;体长与鳞径(R,mm)的关系式为:L=32.61R+6.634。生长规律可用Von Bertalanffy生长方程描述:Wt=776.9599*(1-e-0.14238(t+0.31961))2.887、Lt=294.8954*(1-e-0.14238(t+0.31961)),体重生长拐点年龄t0=7.13a。鄱阳湖鲫的生长参数与其他湖泊中相比,生长系数(k)较小,表明鄱阳湖鲫生长缓慢,从退算体长来看,鄱阳湖鲫表现出小型化趋势,建议采取加强春季禁渔期管理、控制捕捞强度、提高捕捞年龄、保护湖滩草洲生态环境等措施,实现渔业资源增殖。  相似文献   

11.
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.  相似文献   

12.
Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China.  相似文献   

13.
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14.
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.  相似文献   

15.
Growth hormone (GH) and reproduction: a review   总被引：5，自引：0，他引：5  
Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations.  相似文献   

16.
Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL?1 (1.25 ng well?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation.  相似文献   

17.
Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality).  相似文献   

18.
Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg?1 protein) than essential amino acids (425.82 ± 9.15 g kg?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.  相似文献   

19.
The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg–1 fish·h–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g–1·ml–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min–1·g–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min–1·g–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated.  相似文献   

20.
There has been growing concern about the overuse of antibiotics in the ornamental fish industry and its possible effect on the increasing drug resistance in both commensal and pathogenic organisms in these fish. The aim of this study was to carry out an assessment of the diversity of bacteria, including pathogens, in ornamental fish species imported into North America and to assess their antibiotic resistance. Kidney samples were collected from 32 freshwater ornamental fish of various species, which arrived to an importing facility in Portland, Oregon from Colombia, Singapore and Florida. Sixty‐four unique bacterial colonies were isolated and identified by PCR using bacterial 16S primers and DNA sequencing. Multiple isolates were identified as bacteria with potential to cause disease in both fish and humans. The antibiotic resistance profile of each isolate was performed for nine different antibiotics. Among them, cefotaxime (16% resistance among isolates) was the antibiotic associated with more activity, while the least active was tetracycline (77% resistant). Knowing information about the diversity of bacteria in imported ornamental fish, as well as the resistance profiles for the bacteria will be useful in more effectively treating clinical infected fish, and also potential zoonoses in the future.  相似文献   

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