乌江泉水鱼个体生殖力的研究

2011年3-6月和9-12月,在乌江思林江段采集性腺达Ⅲ期的泉水鱼(Pseudogyrinocheilus prochilus)雌鱼个体,测量了卵径,并研究了其个体生殖力及其与多项生物学指标的关系,调查样本由1+～3+龄组成.结果表明,泉水鱼的绝对生殖力(F)平均值为3 606粒,体长相对生殖力(FL)平均值为19.4粒/mm,体重相对生殖力(FW)平均为27.0粒/g;个体绝对生殖力和体长相对生殖力与体重和净体重均呈二次函数相关,与性腺重呈幂函数相关,体重相对生殖力与性腺重和成熟系数分别呈幂函数和对数函数相关.依据卵径频数分布结果推测,泉水鱼属于分批产卵鱼类.     

嘉陵江下游白缘(鱼央)个体生殖力研究

白缘(Liobagrus marginatus Günther)绝对生殖力为70.42(32~118)粒,相对生殖力F/L为0.86(0.52~1.84)粒/mm,F/W为23.25(9.47~38.89)粒/g。绝对生殖力和相对生殖力都与体长(L)、净体重(W)等形态学指标成直线相关,其相关方程分别为F=2.871L-59.581,F=15.332W+22.77,F/L=0.0189L+0.1544,F/W=0.1527W+0.7548。绝对生殖力随年龄的增大而增大,但增大的趋势逐渐减小。相对生殖力随年龄的增大呈现减小趋势。属于分批产卵类型鱼。     

繁殖季节长江口斑尾刺虾虎鱼的形态、生殖力与卵巢组织学特征

在繁殖季节研究了斑尾刺虾虎鱼的形态、生殖力与卵巢组织学特征。结果表明,斑尾刺虾虎鱼全长(TL)与体长(SL)、头长(HL)与体长(SL)、体长(SL)与体高(BD)、体重(BW)与空壳重(SW)、体重(BW)与体长(SL)的相关关系分别为:TL=0.779 6SL+1.793 9;HL=0.299 9SL+7.288;SL=0.783 2BD+7.324 9;BW=0.818 4SW-4.979 6;BW=0.062 9SL2.331 5。斑尾刺虾虎鱼个体绝对生殖力(F)为6 328~59 878 egg,与体长(SL)、空壳重(SW)、卵巢重(OW)的相关关系分别为F=94.972SL2-4 832.2SL+833 435;F=83.823SW+14 084;F=507.54OW+13 190。个体绝对生殖力(F)与体长、空壳重、卵巢重、成熟系数(GSI)的多元回归方程为:F=2 375.54+525.67SL-31.44SW+199.43OW+261.74GSI。斑尾刺虾虎鱼体长相对生殖力(FL)平均为88±31 egg/mm,体重相对生殖力(FW)平均为157±54 egg/g。平均卵径为1.22±0.24 mm。斑尾刺虾虎鱼IV期卵巢以第IV时相卵母细胞为主,第IV时相晚期卵母细胞开始出现油球,细胞核偏移和变形,放射带明显;Ⅴ期卵巢的卵细胞游离,卵膜外的二层滤泡膜脱落,卵细胞的外层分别有胶膜、放射带和质膜。     

沱江史家段四川华吸鳅个体生殖力研究

为了解沱江-史家段四川华吸鳅的个体生殖力,于2018年3-5月采集性腺发育到IV期的雌性四川华吸鳅83尾进行研究。测量所有样本的体长(L)、体质量(M)、净体质量(W)等6种生物学指标,取鳞片鉴定年龄,测定卵粒直径并用重量法计数个体绝对生殖力(F)、体长相对生殖力(FL)以及体质量相对生殖力(FW),用5种数学模型以及回归方程拟合个体生殖力与生物学指标的关系。结果显示,调查样本由2-4龄组成,F为(829.09 ± 627.54)粒,变幅为80-3790 粒；FL为(12.95 ± 8.46)粒/mm,变幅为1.40-48.58 粒/mm；FW为(206.97 ± 114.73)粒/g,变幅为25.21-614.45 粒/g。F和FL与体长、体质量、净体质量、成熟系数和年龄,FW与体长、成熟系数和年龄呈二次函数相关。四川华吸鳅卵径分布只出现了一个较大的峰值,推测其为一次产卵类型。     

光唇鱼雌性个体生殖力的测定

随机采集光唇鱼雌性个体样本12尾,测量其体长(L)、体质量(W)、净体质量(Wn)和性腺质量(Wo)等生物学指标。用质量法计数个体绝对生殖力,并对体长相对生殖力(FL)、体质量相对生殖力(Fw)和成熟系数进行计算,结果表明:个体绝对生殖力(F)在458~14254粒,平均3736粒。体长相对生殖力(FL)在50~1013粒/cm,平均346粒/cm。体质量相对生殖力(Fw)在19~151粒/g,平均85粒/g。绝对生殖力主要集中于1000~5000粒,绝对生殖力在10000粒以上的样本较少。体长相对生殖力主要分布于100~500粒/cm,而体质量相对生殖力主要集中于25~100粒/g。     

东北鳈繁殖力的研究

2018年6—7月,在乌苏里江抚远江段采集了284尾东北鳈Sarcocheilichthys lacustris,研究其生物学体征、种群年龄组成及繁殖力。结果表明:284尾东北鳈中有雌鱼226尾、雄鱼58尾,雌雄比例为3.9∶1;年龄范围1～5龄,3～4龄年龄组个体为优势年龄组,占总样本量的68%;性腺成熟系数(GSI)为(11.27±5.62)%,绝对繁殖力(F)为(5924.69±2177.01)粒,相对繁殖力(F_1)为(60.81±15.25)粒/g,体长相对繁殖力(F_L)为(33.02±10.66)粒/mm,体质量相对繁殖力(F_W)为(49.41±11.61)粒/g;个体绝对繁殖力与体长(L)、体质量(W)及GSI的关系分别为:F=1170.8L-2.6L~2-119577,F=320.65W-0.9W~2-18919,F=143.89GSI~(1.452)。     

洛河鲹鲦个体生殖力的研究

2008年4-5月对洛河野生鲹鲦进行随机取样调查,共收集样本145(雌44,雄101)尾.测定成熟雌鱼体长(L)、体重(W)、年龄(A)、空壳重(BW)、卵巢重(GW)、怀卵量等指标,计数个体绝对生殖力(F),并计算出鲹鲦的体长相对生殖力(FL)、体重相对生殖力(FW)、肥满度(CF)和成熟系数(GSI)等,用6种数学模式拟合了鲹鲦个体生殖力与生物学指标间的关系.结果表明:①成熟雌性鲹鲦由0+-3+龄鱼组成;②个体绝对生殖力(F)范围为1937-39563粒,平均8436粒;体长相对生殖力(FL)范围为190-2586粒/cm,平均735粒/cm;体重相对生殖力(Fw)范围为110-865粒/g,平均383粒/g;③其个体绝对生殖力与体长、体重和年龄都呈抛物线函数相关,体长相对生殖力与体长、体重和年龄分别呈抛物线、直线和抛物线函数相关,体重相对生殖力与它们相关不显著.     

长江干流长鳍吻鮈(Rhinogobio ventralis)繁殖生物学

2012年3月–2014年12月对长江上游宜宾江段采集的521尾野生长鳍吻鮈进行了繁殖生物学研究。结果显示,长鳍吻鮈种群雌雄比为1.41:1,繁殖期为3–5月,盛期为4月上旬至5月上旬。繁殖季节可通过吻端细小"珠星"鉴别雌雄,雄鱼最小性成熟年龄为2~+龄,最小成熟体长为173 mm,体重为90.4 g,成熟系数为0.36%;雌鱼最小性成熟年龄为3~+龄,最小成熟体长为185 mm,体重为119.6 g,成熟系数为11.30%。繁殖群体中,雌性优势龄组为3~+龄,雄性优势龄组为2~+龄和3~+龄。统计结果显示,长鳍吻鮈绝对繁殖力(F)为16399–39835(26816±7875)粒/尾,体重相对繁殖力(F_W)为162–234(189±23)粒/g,体长相对繁殖力(F_L)为877–1659(1231±246)粒/cm。通过对性腺成熟系数、卵径分布频率以及性腺组织切片结果的综合分析认为,长鳍吻鮈属于完全同步产卵类型。     

全人工繁育刀鲚幼鱼的摄食和生长特性

在淡水池塘养殖条件下,对全人工繁育刀鲚幼鱼的摄食和生长特性进行了研究。结果显示:刀鲚为白天摄食类型鱼类,在白天晨昏阶段出现两个摄食高峰,夜间很少摄食。河虾、轮虫和桡足类是刀鲚幼鱼较理想的天然饵料,虾类和轮虫在其食物中的占比分别为37.52%和43.87%,在养殖池配套投放河虾能改善刀鲚在冬季饵料缺乏时期的摄食状况。刀鲚体长与体质量的关系方程为:W=0.095 7L1.536 6,R~2=0.803 2,呈不等速增长;随着养殖时间的增加,体长和体质量上升趋势减缓,体长(L)与养殖时间(t)表现为线性相关:L=-0.0004t~2+0.127 6t+2.798 6(R~2=0.990 3),体质量(W)与养殖时间(t)的相关方程为:W=-0.000 2t~2+0.056 4t+0.370 9(R~2=0.995 7)。试验期间,随着温度的下降,刀鲚的特定生长率下降,生长速度减缓。建议在人工饲养刀鲚过程中,冬季可适当添加浮游生物及河虾等天然饵料。     

杭州湾北部海域凤鲚个体繁殖力初步研究

于2020年5—8月对杭州湾北部海域凤鲚的繁殖力和生物学指标进行了调查和研究。结果表明:5—8月杭州湾凤鲚产卵群体的平均体长(L)和体质量(W)分别为(163.13±24.02) mm和(11.34±5.40) g,体质量(W)与体长(L)呈幂函数正相关,W=0.000 002L3.087 5(R²=0.925)；5—8月杭州湾凤鲚的个体绝对繁殖力平均为(11 683±5 480)粒,个体绝对繁殖力(F)、个体相对繁殖力(FL,FW)与体长(L)、体质量(W)、净体质量(W₂)均呈线性正相关；5—8月凤鲚的平均卵径为(0.707±0.085)mm,各月份之间存在极显著性差异(P＜0.01),其中6月份卵径最大,7月份卵径最小。     

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.     

美人鱼发光杆菌对凡纳滨对虾非特异性 免疫功能及抗病力的影响

在基础饲料中分别添加0.1%和1%美人鱼发光杆菌灭活菌、0.1%美人鱼发光杆菌活菌配制成3种免疫实验饲料,以基础饲料为空白对照组饲料,每组设3个平行样。对个体质量为(4.83±0.36)g的凡纳滨对虾进行为期20 d的饲养实验,分别在0、5、10、15和20d进行取样,以血清中的酚氧化酶(PO)、酸性磷酸酶(ACP)、碱性磷酸酶(AKP)、超氧化物歧化酶(SOD)和溶菌酶(UL)活性为免疫指标,探讨了美人鱼发光杆菌作为免疫制剂对凡纳滨对虾非特异性免疫效应的影响;在投喂免疫饲料后的第22天,按0.004 2 kg/kg体重的剂量,直接投喂对虾白斑综合征病毒(WSSV)病料,并记录累积死亡率。结果表明,美人鱼发光杆菌免疫实验组对凡纳滨对虾血清中PO、ACP、AKP、UL和SOD活性影响明显高于对照组,并且在饲料中添加美人鱼发光杆菌后,明显提高了对虾抵御WSSV感染的能力。其中0.1%美人鱼发光杆菌活菌实验组的抗病毒感染能力最强,WSSV感染14d内累计死亡率为63.3%±5.8%;而对照组为96.7%±3.3%。研究表明,美人鱼发光杆菌添加在对虾饲料中能提高凡纳滨对虾非特异性免疫水平,增强抵抗疾病的能力,将其作为对虾免疫增强剂具有良好的应用前景。     

Effects of Spirulina platensis as a feed additive on growth and coloration of blue dolphin cichlids (Cyrtocara moorii Boulunger, 1902)

This study was carried out to investigate the effects of replacing fish meal with dietary Spirulina as a feed supplement on the growth performance and coloration of blue dolphin cichlids (Cyrtocara moorii). Five isonitrogenous (47% crude protein) and isocaloric (17.36 kJ/g digestible energy) diets were for formulated to replace FM with 0, 5, 10, 15 and 20% Spirulina (designated as Control, SP5, SP10, SP15 and SP20 respectively) and fed to the fish (initial body weight, 3.15 ± 0.01 g). Fish were randomly distributed into fifteen 120 L aquariums (26.5 ± 1.00°C), 15 fish per aquarium. The diets were tested in triplicate for 12 weeks. Experimental groups were fed twice daily (09:00 and 17:00) by hand to satiation. At the end of the feeding trial, significantly (p < 0.05) higher weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER) and lower feed conversion ratio (FCR) were observed in fish fed the SP10 diet when compared to the SP20 diet. There was no significant difference in these parameters between the other groups. The skin coloration of blue dolphin cichlid fed a diet containing Spirulina meal was enhanced. The best coloration was observed in the SP15 group. These impressions were objectively validated by chemical determinations of carotenoids extracted from fish skins and passed statistical tests of significance. The study findings show that Spirulina meal does not diminish growth rates except at very high levels.     

A Minchinia mercenariae‐like parasite infects cockles Cerastoderma edule in Galicia (NW Spain)

The cockle Cerastoderma edule fishery has traditionally been the most important shellfish species in terms of biomass in Galicia (NW Spain). In the course of a survey of the histopathological conditions affecting this species in the Ria of Arousa, a haplosporidan parasite that had not been observed in Galicia was detected in one of the most productive cockle beds of Galicia. Uni‐ and binucleate cells and multinucleate plasmodia were observed in the connective tissue mainly in the digestive area, gills and gonad. The parasite showed low prevalence, and it was not associated with abnormal cockle mortality. Molecular identification showed that this parasite was closely related to the haplosporidan Minchinia mercenariae that had been reported infecting hard clams Mercenaria mercenaria from the Atlantic coast of the United States. The molecular characterization of its SSU rDNA region allowed obtaining a fragment of 1,796 bp showing 98% homology with M. mercenariae parasite. Phylogenetic analysis supported this identification as this parasite was clustered in the same clade as M. mercenariae from the United States and other M. mercenariae‐like sequences from the UK, with bootstrap value of 99%. The occurrence of M. mercenariae‐like parasites infecting molluscs outside the United States is confirmed.     

Sea bream culture in Egypt; status, constraints and potential

Marine fish farming in Egypt began in 1976 with the culture of gilthead sea bream, (Sparus aurata) as this fish was notably adaptable to brackish and marine pond conditions. Today, marine fish and shrimp farms amount to about 19,000 ha, out of which 42% is already in production while the rest, i.e., 58% is still under construction. In 1997, cultured gilthead sea bream production of 2,250 tons made up 3% of the 75,000 tons total aquaculture catch. In polyculture, usually with the grey mullet and sea bass, gilthead sea bream contributed 440 kg ha^–1 to the total yield of 1,700 kg ha^–1 (26%) over a period of 16 months. For the same period, the yield of monoculture ponds averaged 100 kg ha^–1, while in marine cages, yields ranged from 4–10 kg m³. In 1996–1997, fry of 0.25–1 g and fingerlings 1–10 g with a total of 3 million, were collected from the wild and 1 million fry were produced in the three marine hatcheries out of the four existing ones. The development of sea bream culture in Egypt is now severely inhibited by the shortage of seeds and adequate feeds. Exports of both sea bream and sea bass, during 1994–1996 averaged 1,300 tons per year.     

Dietary thiamin and pyridoxine requirements of fingerling Indian major carp,Cirrhinus mrigala (Hamilton)

Two experiments were conducted to quantify the dietary thiamin (experiment I) and pyridoxine (experiment II) requirements of fingerling Cirrhinus mrigala for 16 weeks. In experiment I, dietary thiamin requirement was determined by feeding seven casein–gelatin‐based diets (400 g kg^?1 CP; 18.69 kJ g^?1 GE) with graded levels of thiamin (0, 0.5, 1, 2, 4, 8 and 16 mg kg^?1 diet) to triplicate groups of fish (6.15 ± 0.37 cm; 1.89 ± 0.12 g). Fish fed diet with 2 mg kg^?1 thiamin had highest specific growth rate (SGR), protein retention (PR), RNA/DNA ratio, haemoglobin (Hb), haematocrit (Hct), RBCs and best feed conversion ratio (FCR). However, highest liver thiamin concentration was recorded in fish fed 4 mg thiamin kg^?1 diet. Broken‐line analysis of SGR, PR and liver thiamin concentrations exhibited the thiamin requirement in the range of 1.79–3.34 mg kg^?1 diet (0.096–0.179 μg thiamin kJ^?1 gross energy). In experiment II, six casein–gelatin‐based diets (400 g kg^?1 CP; 18.69 kJ g^?1 GE) containing graded levels of pyridoxine (0, 2, 4, 6, 8 and 10 mg kg^?1 diet) were fed to triplicate groups of fish (6.35 ± 0.37 cm; 1.97 ± 0.12 g). Fish fed diet containing 6 mg kg^?1 pyridoxine showed best SGR, FCR, PR, RNA/DNA ratio, Hb, Hct and RBCs, whereas maximum liver pyridoxine concentration was recorded in fish fed 8 mg kg^?1 dietary pyridoxine. Broken‐line analysis of SGR, PR and liver pyridoxine concentrations reflected the pyridoxine requirement from 5.63 to 8.61 mg kg^?1 diet. Data generated during this study would be useful in formulating thiamin‐ and pyridoxine‐balanced feeds for the intensive culture of this fish.     

Fertilization by refrigerator stored sperm of the Indian major carp, Labeo calbasu (Hamilton, 1822)

This study reports on the spermatological properties, and on the development of a protocol for refrigerator storage (4°C) of Labeo calbasu (Hamilton, 1822) sperm for artificial breeding. Volume, motility, concentration and pH of the freshly collected sperm were 2.21 ± 0.53 (μL g^?1 of fish weight) (mean ± SD), 95 ± 1 (%), 1.93 ± 0.44 × 10⁹ (cells mL^?1) and 7.56 ± 0.17 respectively. Sperm activation was evaluated at different osmolalities of NaCl solution, and motility ceased completely when osmolality of the extender was ≥287 mOsmol kg^?1. Sperm retained motility for 24, 72 and 108 h, after refrigerator storage when sperm were undiluted, suspended in Alsever's solution and suspended in Alsever's solution containing 5% methanol respectively. Fertilization rate of fresh eggs with sperm stored at 4°C in Alsever's solution and Alsever's solution containing 5% methanol was 77% and 60% with a hatching rate of 60% and 43% respectively. The fertilization and hatching success of the stored sperm suggests potential to use refrigeration for transporting genetic material to hatcheries for artificial breeding of L. calbasu in Bangladesh.     

A novel approach to denitrification processes in a zero-discharge recirculating system for small-scale urban aquaculture

This paper presents an innovative process to solve the nitrate build-up problem in recirculating aquaculture systems (RAS). The novel aspects of the process lie in a denitrification bioreactor system that uses solid cotton wool as the primary carbon source and a unique degassing chamber. In the latter, the water is physically stripped of dissolved gaseous O₂ (by means of a Venturi vacuum tube), and the subsequent denitrification becomes more efficient due to elimination of the problems of oxygen inhibition of denitrification and aerobic consumption of cotton wool. The cotton wool medium also serves as a physical barrier that traps organic particles, which, in turn, act as an additional carbon source for denitrification. Operation in the proposed system gives an extremely low C/N ratio of 0.82 g of cotton wool/g of nitrate N, which contributes to a significant reduction of biofilter volume. The additional advantage of using solid cotton wool as the carbon source is that it does not release organic residuals into the liquid to be recycled. Operation of the system over a long period consistently produced effluents with low nitrate levels (below 10 mg N/l), and there was only a very small need to replace system water. The overall treatment scheme, also incorporating an aerobic nitrification biofilter and a granular filtration device, produced water of excellent quality, i.e., with near-zero levels of nitrite and ammonia, a sufficiently high pH for aquaculture, and low turbidity. The proposed system thus provides a solution for sustainable small-scale, urban aquaculture operation with a very high recovery of water (over 99%) and minimal waste disposal.     

Effects of metomidate anaesthesia or transfer to pur sea water on plasma parameters in ammonia-exposed Atlantic salmon (Salmo salar L) in sea water

Atlantic salmon (Salmo salar L) postsmolts weighing 150 ± 53 g were exposed to 14–15 mg l^–1 TA-N (total ammonia-N) in sea water in 1 m³ tanks for 24h. Blood samples were then taken A) immediately after the fish were netted from the exposure tanks and stunned by a blow to the head; B) 2–20 min after the fish were transferred to 15 l of an anaesthetic solution of metomidate in ammonia-free sea water; or C) 2–20 min after the fish were transferred to 15 l of ammonia-free sea water. Plasma TA-N level was 18% lower in the anaesthetised fish compared to in the fish sampled directly from the exposure tanks (p 0.05), and accordingly 16% lower in the fish transferred to pure sea water although this difference was not significant (p = 0.07). Plasma glucose level was higher in the fish transferred to pure sea water than in the fish receiving the two other treatments (p 0.05), but plasma urea, osmolality, Na^{+, Cl–, Ca2+ or Mg2+} levels did not vary significantly between the different treatments. Plasma TA-N level increased with time in the fish in the metomidate solution (p 0.02).