叶尔羌高原鳅耗氧率和窒息点的初步研究

试验测定了叶尔羌高原鳅的耗氧率和窒息点。结果表明:叶尔羌高原鳅的耗氧率具有昼夜节律性,耗氧高峰在23:00左右,低谷在10:00左右,其耗氧率和窒息点随体重的增加而降低,随水温的升高而增大。     

叶尔羌高原鳅低温下耗氧率和窒息点的研究

试验采用流水呼吸室法和静水呼吸室法测定了叶尔羌高原鳅在低温6.5~7.5℃条件下的耗氧率和窒息点。结果表明,叶尔羌高原鳅耗氧率具有昼夜节律性,耗氧高峰在5:00左右,低谷在15:00左右,其耗氧率和窒息点随体重的增加而增加,随水温的升高而增大。叶尔羌高原鳅适应低温能力较强,适宜生长温度6~29℃,最佳生长温度8~15℃。     

巴沙鱼幼鱼耗氧率和窒息点的初步研究

在平均水温27．0℃条件下，测得平均全长11．1cm、平均体重12．0g的巴沙鱼幼鱼的耗氧量为3．8926mg／（尾·h），耗氧率为0．3237mg／（g·h），窒息点为0．5297mg／L。巴沙鱼昼间耗氧率明显高于夜间耗氧率，其对低氧的耐受力较强。     

中华乌塘鳢耗氧率和窒息点的研究

对两种规格中华乌塘鳢的窒息点和在不同水温条件下的耗氧率进行了测定。结果表明,水温和体重对中华乌塘鳢的耗氧率有显著影响。水温从16℃上升到32℃,大规格鱼（平均体重40.2g）的耗氧率从37.34mg/kg·h增加到136.72mg/kg·h;小规格鱼（平均体重18.0g）的耗氧率从42.81mg/kg·h增加到203.62mg/kg·h。水温与耗氧率的关系可用幂函数表示。水温25℃时,大小两种规格中华乌塘鳢的窒息点分别为0.2744mg/L和0.3031mg/L。     

兰州鲇苗种阶段耗氧率与窒息点初探

不同规格兰州鲇耗氧率随着个体重量的增加而降低、而窒息点随体重的增加而增加。平均尾重1．09g和10．6g兰州鲇苗种，在水温17．7～22．0℃时，昼夜的平均耗氧率分别为209．82mg／kg·h和158．91mg／kg·h，窒息点分别为0．6531mg／L和0．8108mg／L。     

中华倒刺鲃鱼种耗氧率和窒息点的初步研究

在一定水温条件下 ,对中华倒刺鱼种 (1 5 5～ 7 2 8g)进行了耗氧率和窒息点的测定 ,结果表明 :耗氧率随鱼体体重的增加而降低。平均体长 4 35cm ,均重 1 5 5 g的个体 ,平均耗氧率为 0 42 0 2mg/g·h ,窒息点为0 441 2mg/L ,平均体长 7 2 2cm ,均重 7 2 8g的个体 ,平均耗氧率为 0 2 2 2 2mg/g·h ,窒息点为 0 8831mg/L。水温与耗氧率呈正相关。     

华鲮鱼种耐氧力与耐酸碱性研究

在适宜生长温度上、下限的条件下，对2种不同规格的华鲮鱼种进行耗氧率、窒息点和耐酸碱性的测定。结果表明：耗氧率随着鱼体体重的增加而降低、而窒息点随体重的增加而增加。平均尾重6．13g～12．58g的华鲮鱼种在水温13．012～29．0℃时耗氧率为0．1495mg／g．h～0．1071mg／g.h，窒息点分别为0．1395mg／L～0．1572mg／L；其生长的最适宜pH为6．5—7．5。     

山女鳟耗氧量与体重、水温的关系的研究

通过对体重0．53g和75．58g的山女鳟，在7℃、10℃、13℃、16℃、19℃，5个范围耗氧的测定，研究了山女鳟耗氧量与体重、水温的关系，结果表明：耗氧量随着体重和水温的增加而增加，耗氧率随着体重的增加而减少，在13℃-16℃水温范围内，水温增加但耗氧率增加不明显，水温在16℃时，耗氧量与体重的关系为：R=0．3621W^7848(R：耗氧量mg／h．尾，W：体重，g)，在体重0．53g时，耗氧量与水温的关系为：R=0．0173T-0．0393，75．58g时，耗氧量与水温的关系为：R=0．825T-1．725(R：耗氧量mg／h．尾，T：水温，℃)。山女鳟耗氧率具有昼夜变化，表现出明显的节律性，在13：00时耗氧率达到最高值，22：00时达到最低值。山女鳟的窒息点在1．2—1．98mg／L。     

暗纹东方Tun鱼苗耗氧率和窒息点的初步研究

对暗纹东方鱼屯两个规格鱼苗的耗氧量、耗氧率和窒息点进行了测定.结果显示在水温31～34℃,pH 6.5～6.8条件下,平均全长2.36 cm、体重0.429 g的鱼苗24 h平均耗氧量0.321 mg/(尾·h),耗氧率1.149 mg/(g·h),窒息点1.309 mg/L;平均全长3.49 cm、体重0.569 g的鱼苗24 h平均耗氧量0.837 mg/(尾·h),耗氧率0.968 mg/(g·h),窒息点1.486 mg/L.     

美国大口胭脂鱼苗种耗氧率和窒息点试验

对美国大口胭脂鱼的耗氧率、耗氧量及窒息点进行了测定。①耗氧率：平均体长6．9cm，体重6．7克的美国大口胭脂鱼的耗氧率为0．1641mg／g.hr，耗氧量1．115mg／尾．hr；平均体长7．0cm，平均体重6：87克的美国大口胭脂鱼耗氧率0．1433ndg／ghr，耗氧量0.1324mg／尾hr；平均体长10cm，体重24．05克的美国大口胭脂鱼耗氧率随体重增加而减小，而耗氧量随鱼体体重增加而增大。大口胭脂鱼的耗氧量呈现出明显的昼夜变化规律。②窒息点：美国大口胭脂鱼（6．9－10cm）的窒息点在水温30．6－32．1℃时为0．3000－0．3500mg／L。     

Food and feeding habits of Tilapia aurea (Steindachner) (Cichlidae) in Lake Kinneret (Israel)

An analysis of the food of 274 specimens of Tilapia aurea (Steindachner), which had been collected in Lake Kinneret, showed that this species is mainly a zooplankton consumer.A study of the quantitative dynamics of the food components in the course of a year has proved that the species in question feeds more intensely in spring, this being the time when zooplankton forms are more abundant in the water of the lake. Vegetable detritus, mixed with plankton and benthos forms, served as additional and alternative food.The lack of clearly positive degree of food component selectivity, as well as the low values of the intestine repletion index and of the condition coefficient, account for the slowness in growth of Tilapia aurea in Lake Kinneret.The low values of the growth and feeding indices are due, according to the authors, to the pressure brought to bear by the other local fish species, which are competitors for the same food.     

Food and feeding habits of Tilapia zillii (Gervais) (Cichlidae) in Lake Kinneret (Israel)

Analysis of the gut content of 329 specimens of T. zillii (Cichlidae) collected from Lake Kinneret, has shown great variation in the sorts of food.A study of seasonal dynamics has proved the prevalence in the food of Chironomida pupae (Diptera) in winter and spring and of zooplankton forms in summer and autumn. The additional food consisted of the various groups of algae, the most frequently found being Cyanophyta (100%) and Pyrrophyta (64.16%). An extremely voraceous species, it consumes — while searching for its preferred food — anything that comes its way in the water: algae, scraps of macrophytes, autochthonous and allochthonous insects, and forms of benthic origin, such as Nematoda, Ostracoda, Porifera and Chironomida (larvae).The satiation index is high (between 4.08 and 5.63), in contradiction to the low values of the coefficient of condition (between 3.05 and 3.51), and with the slow rate of growth in Lake Kinneret. The main food of Tilapia zillii, consists of arthropod species with a chitin content (which is eliminated unchanged) of more than 50% of the total weight, and this may account for the poor exploitation of the trophic base.This species of fish may be considered as being detrimental to others (i.e. commercially important species) because of its successful competition for food, and not, as is often incorrectly assumed, because it is an aggressive consumer of their spawn and fry.     

不同品系尼罗罗非鱼致死低温的研究

在室内自然降温条件下，研究了三个品系尼罗罗非鱼（吉富品系，“７８”品系，“８８”品系）对低温的耐受力，计算得出每个品系的半致死低温，并对降温过程中尼罗罗非鱼行为活动的变化进行了观察。试验结果表明，在上海地区，当温度降低到１１℃时，罗非鱼开始死亡，到７．４℃时，全部死亡。吉富罗非鱼死亡温度范围是１１℃￣８．４℃，“７８”品系是９．８￣７．４℃，“８８”品系是１１℃￣７．４℃。对三个品系半致死低温的研     

Grass carp (Ctenopharyngodon idella) grazing on duckweed (Spirodela polyrhiza)

The aims of this experiment were (1) toquantify the ability of grass carp to processduckweed and (2) to assess indirect changes inwater chemistry and phytoplankton community,caused by grass carp feeding. Yearling grass carp sized 126 ± 7.7 mm (TL) and19.6 g in weight were kept in 9 laminate tanksof 1 m³ for 14 days. Two stockingdensities (2 and 6 fish per m³) anda control without fish were used. Standard growthrate (SGR) of grass carp fed exclusively onduckweed was 0.70% body weight (BW) d^–1and food conversion ratio (FCR) reached 2.0(average water temperature =21.1 ± 3.8 °C). Daily food intakewas 0.2 g of duckweed dry weight (DW), i.e.,1% of average BW of grass carp. SGR ofduckweed growing in 20 × 20 cm floatingenclosures, differed significantly[F(6,2) = 417.9; p = 0.002] between the twostocking densities of grass carp and thecontrol tanks (without fish). Mean SGR ofduckweed was 0.02 g g^–1 day^–1 and thehighest SGR was recorded in the control tanks.Both decrease in NH₄-N and increase inNO₂-N concentrations differedsignificantly between the treatments[F(2,2) = 45.3; p = 0.02 and F(2,2) = 19.2; p = 0.04 respectively]. Changes in other nitrogenand phosphorus components (NO₃-N, TN, TPand PO₄-P) caused by stocking of grasscarp were not significant. Biomass ofphytoplankton, dominated by filamentous algaeand blue-greens, increased proportionately tostocking density of grass carp. Althoughduckweed has a large potential for nutrientremoval, the most common pathway for thenutrients released through grass carp grazingif duckweed cover is loose is theirincorporation into phytoplankton biomass.     

叶尔羌高原鳅胚胎发育与胚后发育观察

采用形态学和生态学方法,对叶尔羌高原鳅[Triplophysa(Hedinichthys)yarkandensis(Day)]胚胎发育和胚后发育阶段全过程进行观察、拍照并测量。结果显示:叶尔羌高原鳅,卵微黏性,略有沉性,受精卵呈卵圆形,卵径为(0.60±0.052)mm,在水温(20.0±1.0)℃下,历时65 h 34 min完成整个胚胎发育分为7个生理阶段过程;胚后发育主要根据卵黄囊、体色、鼓鳔和须的变化分为仔鱼期、稚鱼期、幼鱼期。初孵卵黄囊仔鱼全长(2.0±0.65)mm,出膜后7 d,卵黄囊吸收完毕,完全消失;初孵仔鱼继续培育至16日龄,仔鱼鳃盖后缘鼓鳔明显长出,须清晰可辨,体色加深,心脏红色素明显,体色与成体相似,标志后期仔鱼发育完全进入稚鱼期,此时鱼苗全长(8.0±0.45)mm;培育至30日龄,仔鱼鼓鳔完全,鳃盖张合明显,身体透明特征消失,稚鱼阶段完成发育进入幼鱼期,此时全长达(13.0±0.55)mm,其外部形态和生态习性均与成鱼相似。试验中,卵黄囊长度(LY)和出膜天数(D)的关系式:LY=0.0286D2–0.0636D+3.1196(R2=0.9050);用直线方程拟合卵黄囊长度(LY)和卵黄囊仔鱼全长(LT)的关系式:LY=–1.315LT+5.368(R2=0.8199);拟合卵黄囊仔鱼全长(LT)和出膜后仔稚鱼天数(D)的关系式:LT=–0.0263D2+0.5113D+1.6169(R2=0.9890)。本研究旨在通过了解叶尔羌高原鳅的早期发育特征为该物种的保护和增殖对策提供科学依据,并对其苗种生产提供理论指导。     

Extinction of Daphnia lumholtzi (Sars) in Lake Kinneret (Israel)

Daphnia lumholtzi (Sars) was found in Lake Kinneret until the late nineteen-fifties. Lake Kinneret was the northern-most limit of the distribution of this species. It is suggested that fingerlings of grey mullets and Sarotherodon aureus that were introduced into Lake Kinneret caused the extinction of D. lumholtzi.     

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.     

Development of embryos in Mastacembelus mastacembelus (Bank & Solender, 1794) (Mesopotamian spiny eel) (Mastacembelidae)

In this study, the embryonic development of the eggs in the Mastacembelus mastacembelus (Bank & Solender, 1794) was examined. At the same time, possibilities of artificial breeding through artificial insemination were investigated. Artificial insemination was achieved by mixing the eggs of the mature female and sperm of the mature male samples caught with gill nets (22 × 22) in Ataturk Dam Lake in Turkey. To this end, first in a Petri dish (100 × 20), the testes were cut into small pieces with a lancet and the mixture of sperm–testes‐tissue was obtained. The fertilization rate of the eggs was found to be 80%. The diameter of the eggs ranged from 2.015to 1.147 mm. The perivitelline space formed 0.5 h after insemination. The first cleavage occurred at the animal pool 4 h after insemination. The oil droplets had fused to a single droplet 19 h after insemination. The blastoderm became an embryonic shield 30 h after insemination. The blastoderm covered almost half the egg 40 h after insemination and embryonic body was formed. The blastoderm covered almost the whole egg 50 h after insemination. Some somites were discernible 59 h after insemination. The embryonic body reached two‐third of the circumference of the egg 70 h after insemination. The tail bud began to separate from the yolk 77 h after insemination. A newly hatched larva was observed at 85 h after insemination.     

Transmission of white spot syndrome virus (WSSV) from Dendronereis spp. (Peters) (Nereididae) to penaeid shrimp

Dendronereis spp. (Peters) (Nereididae) is a common polychaete in shrimp ponds built on intertidal land and is natural food for shrimp in traditionally managed ponds in Indonesia. White spot syndrome virus (WSSV), an important viral pathogen of the shrimp, can replicate in this polychaete (Desrina et al. 2013); therefore, it is a potential propagative vector for virus transmission. The major aim of this study was to determine whether WSSV can be transmitted from naturally infected Dendronereis spp. to specific pathogen‐free (SPF) Pacific white shrimp Litopenaeus vannamei (Boone) through feeding. WSSV was detected in naturally infected Dendronereis spp. and Penaeus monodon Fabricius from a traditional shrimp pond, and the positive animals were used in the current experiment. WSSV‐infected Dendronereis spp. and P. monodon in a pond had a point prevalence of 90% and 80%, respectively, as measured by PCR. WSSV was detected in the head, gills, blood and mid‐body of Dendronereis spp. WSSV from naturally infected Dendronereis spp was transmitted to SPF L. vannamei and subsequently from this shrimp to new naïve‐SPF L. vannamei to cause transient infection. Our findings support the contention that Dendronereis spp, upon feeding, can be a source of WSSV infection of shrimp in ponds.