高白鲑养殖、繁殖技术的研究总结报告

高白鲑系鲑科白鲑属鱼类,原产苏联,我国引进后进行人工孵化、仔鱼饲育、鱼种培育、亲鱼饲养、人工产卵、孵化、获得了仔代.本文详细介绍了仔鱼饲育条件、技术,成活率达71.15%～85.64%.鱼种培育采用常规方法,但易患鱼病,影响成活率.亲鱼培育采用流水集约化养殖于11月下旬达性成熟进行人工繁殖,本文介绍了人工采卵,授精、脱粘、洗卵及人工孵化技术.     

高白鲑养殖、繁殖技术的研究总结报告

高白鲑系鲑科白鲑属鱼类，原产苏联，我国引进后进行人工孵化、仔鱼饲育、鱼种培育、亲鱼饲养、人工产卵、孵化、获得了仔代。本详细介绍了仔鱼饲育条件、技术，成活率达71．15％－85．64％。鱼种培育采用常规方法，但易患鱼病，影响成活率。亲鱼培育采用流水集约化养殖于11月下旬达性成熟进行人工繁殖，本介绍 了人工采卵，授精、脱粘、洗卵及人工孵化技术。     

黄河上游拉西瓦水库欧白鲑Coregonus albula个体繁殖力研究

2012年3月，从芬兰引进欧白鲑(Coregonus albula)发眼卵40万粒，孵出仔鱼培育出平均体质量2.0 g/尾的鱼种放入青海省拉西瓦水库网箱养殖。2018年，网箱养殖欧白鲑平均体质量3 kg以上。实验在2019年2月捕捞41尾雌鱼，11尾雄鱼,研究欧白鲑亲鱼在我国青藏高原东北部的形态特征、个体繁殖力特征及个体繁殖力与生物学指标的相关性。结果显示，欧白鲑个体绝对繁殖力平均为77 600粒，个体体长相对繁殖力平均值1 564 eggs·cm^-1，体质量相对繁殖力平均25.2 eggs·g^-1。雌亲鱼性腺成熟系数在14.8%～52.6%之间，平均为32.4%；肥满度为0.019 g·cm^-3～0.032 g·cm^-3之间，平均为0.025 g·cm^-3。欧白鲑雌性亲鱼卵巢重与体质量、体长和体高呈极显著的正相关性。欧白鲑的个体绝对繁殖力与卵巢重量、体质量、体长和体高呈极显著的相关性。性腺成熟指数、肥满度与体高呈极显著的相关性。欧白鲑亲鱼体高与其个体繁殖力具有很好的相关性，可...     

俄罗斯白鲑育苗及养殖技术

俄罗斯范围内有白鲑属鱼类约15种,其中肉质好、经济价值较高、巳被选择为增养殖对象的有高白鲑、齐尔白鲑、目笋白鲑、楚德白鲑、拉多加白鲑、图贡白鲑等。近几年,我国已成功地引进移植了高白鲑、凹自白鲑。现将俄罗斯白鲑鱼类     

白鲑属鱼类国内增养殖现状

白鲑属鱼类隶属于鲱形目、鲑亚目、鲑科、白鲑亚科。世界上约有30余种。广泛分布于北纬500以北的广大淡水水域，是欧洲、北美、亚洲北部的经济鱼类。也是重要的增养殖对象。据报道，目前引进我国的白鲑属鱼类有：高白鲑(Coregonus Peled)、加拿大白鲑(Coregonus arledii Lesueur)、凹目白鲑、齐尔白鲑、图冈白鲑。     

赛里木湖高白鲑性腺发育观测

高白鲑(Coregouns peled)属鲑科冷水性鱼类,其主要分布在北纬50度以上的河流、湖泊中,尤以俄罗斯西伯利亚地区的鄂毕河流域为多.由于该鱼适应性强,肉味美,易捕捞,长势快,又是典型的食浮游动物的鱼类,早在上世纪30年代前苏联已将高白鲑作为重要的增养殖开发对象,在其境内冷水水域广泛移植和推广.我国黑龙江省于1985年从日本国引进过高白鲑,并在池塘进行过养殖和人工繁殖试验.然而对高白鲑在大型水域引种移植和在天然水域中直接进行人工繁殖在我国尚未进行.1998年以来新疆连续3年从俄罗斯引种高白鲑发眼卵700万粒,经孵化向赛里木湖移植高白鲑鱼苗300万余尾.1998～1999年通过跟踪观测,高白鲑在赛里木湖生长发育良好.为使高白鲑苗种本地化,2000年我们对赛里木湖高白鲑的性腺发育规律进行了观测,以掌握其在赛里木湖水域中性腺成熟度的变化规律,为高白鲑的人工繁殖做好准备,同时作者还对高白鲑在赛里木湖的食性变化进行了观测.     

齐尔白鲑亲鱼培育及繁殖试验

正齐尔白鲑Coregonus nasus(pall.)属鲑科、白鲑亚科(Coregonusegoninae)、白鲑属(Coregonus)。天然分布于伯绍拉河至阿纳德尔河一带北美洲水域内,是俄罗斯重要的经济白鲑鱼类品种。其适宜生长水温11℃以下,生长快,个体大,肉质细腻,被称之为"极地鲤鱼",以底栖生物为食,喜生活在河湖接壤处。齐尔白鲑也是一种优良的集约化养殖的冷水鱼,可以在适宜的流水池、网箱进行养殖,具有很高的养殖效益。该鱼一般6~7龄达到性成熟,条件好时3~4龄可性成熟,亲鱼重量1.8~3.5千克,怀卵     

三种不同来源红鳍东方鱼屯亲鱼的卵质比较

对于红鳍东方鱼屯(Takifugurubripes)的苗种生产以往都是依靠捕获的天然成熟亲鱼由人工采卵而获得。近年来，日本长崎县和鹿儿岛附近的产卵场亲鱼捕获量剧减，要从刚捕获的亲鱼中采卵已十分困难。最近试验了对即将成熟的亲鱼注射白鲑脑垂体和促性腺激素...     

赛里木湖高白鲑性腺发育观测

高白鲑 (Ｃｏｒｅｇｏｕｎｓｐｅｌｅｄ)属鲑科冷水性鱼类 ,其主要分布在北纬 5 0度以上的河流、湖泊中 ,尤以俄罗斯西伯利亚地区的鄂毕河流域为多。由于该鱼适应性强 ,肉味美 ,易捕捞 ,长势快 ,又是典型的食浮游动物的鱼类 ,早在上世纪 30年代前苏联已将高白鲑作为重要的增养殖开发对象 ,在其境内冷水水域广泛移植和推广。我国黑龙江省于 1985年从日本国引进过高白鲑 ,并在池塘进行过养殖和人工繁殖试验。然而对高白鲑在大型水域引种移植和在天然水域中直接进行人工繁殖在我国尚未进行。 1998年以来新疆连续 3年从俄罗斯引种高白鲑发眼卵 7…     

三种不同来源红鳍东方鱼屯亲鱼的卵质比较

对于红鳍东方鱼屯（Ｔａｋｉｆｕｇｕｒｕｂｒｉｐｅｓ）的苗种生产以往都是依靠捕获的天然成熟亲鱼由人工采卵而获得。近年来，日本长崎县和鹿儿岛附近的产卵场亲鱼捕获量剧减，要从刚捕获的亲鱼中采卵已十分困难。最近试验了对即将成熟的亲鱼注射白鲑脑垂体和促性腺激素...     

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.     

Rare serotype occurrence and PFGE genotypic diversity of Streptococcus agalactiae isolated from tilapia in China

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.     

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.     

Growth hormone (GH) and reproduction: a review

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.     

Purification and partial characterization of GtHs (cfLH and cfFSH) from Indian walking catfish (Clarias batrachus) (L.) and development of a homologous ELISA for cfLH

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.     

Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection

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).     

Protein and amino acid composition from the mantle of juvenile O ctopus vulgaris exposed to prolonged starvation

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.     

Nitrogenous waste excretion and accumulation of urea and ammonia inChalcalburnus tarichi (Cyprinidae), endemic to the extremely alkaline Lake Van (Eastern Turkey)

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.     

Imported ornamental fish are colonized with antibiotic‐resistant bacteria

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.