Golden Shiner Notemigonus crysoleucas× Rudd Scardinius erythrophthalmus Hybrids: Gonad Histology and Spawning Trials

Hybrid fish were produced in ponds by crossing golden shiners × rudd ( Notemigonus crysoleucas × Scardinius erythrophthalmus ) and rudd × golden shiners. Histologically, testes from the hybrids contained spermatocytes that resembled those of the parental species, but no sperm were observed. Lack of sperm in hybrids could have been a seasonal effect. The ovaries of both types of hybrids contained variable numbers of morphologically normal, vitellogenic oocytes and numerous abnormal oocytes in the chromatin nucleolar stage. Abnormal oocytes were necrotic or had irregularly shaped nuclei and clumped chromatin. Many oocyte nests contained infiltrating macrophnges. Spawning trials with F₁ hybrids did not result in spawning behavior or production of F₂ generation fish. Colden shiner × rudd hybrids are of reduced fecundity, but sterility was not conclusively demonstrated.     

Ineffectiveness of Water Circulation for Golden Shiner Notemigonus crysoleucas Production in Ponds

Abstract— Continuous aeration at 0.5–0.9 kWha during summer months increasingly has become a baitfish industry practice, with aerators also serving as water circulators. Our study examined the impact of circulating pond water on golden shiners Notemigonus crysoleucas produced by typical commercial practices. Ponds (0.04-ha) were circulated with 0.25-kW pumps during two consecutive summers. In the first trial juvenile golden shiners were stocked at 282,800/ha and treatment ponds circulated from 0900–1600 h. In the second trial, stocking rate and daily hours of circulation were increased (800,600 fishha and 24 h, respectively). After 56 d (trial 1). gross yields (mean ± SE) were 771 ± 69 and 668 ± 44 kgha for control (uncirculated) and circulated ponds, respectively. Second trial gross yields (63 d) were 1,330 ± 70 and 1,177 ± 61 kgha for the control and circulated treatments, respectively. While circulated ponds showed a reduction in stratification based on temperature and dissolved oxygen profiles, there were no significant differences in golden shiner growth, yield or survival. Under the conditions of our trials, water circulation was an ineffective culture practice.     

Polyculture of the Giant Malaysian Prawn and the Golden Shiner in Southwestern Louisiana1

Juvenile prawns (Macrobrachium rosenbergii) were stocked at 37,050/ha and golden shiner (Noremigonus crysoleucas) fry at 321,100/ha into 16 earthen ponds at Rockefeller Wildlife Refuge, Grand Chenier, Louisiana. Four replicated treatments were tested: fed prawn monoculture, fed shiner monoculture, fed prawn and fed shiner polyculture, and unfed prawn fed shiner polyculture. The study lasted 149 days. There were no significant differences in growth between prawns fed in monoculture and prawns fed in polyculture (P > 0.05). However, fed prawns grew significantly larger (P < 0.05) than unfed prawns. Prawn survival in all treatments combined averaged 63%. Survival was significantly higher (P < 0.05) for fed prawns than for unfed prawns. Prawn yields averaged 533 kg/ha, when all treatments were combined. Yield was significantly higher (P < 0.05) for prawns grown with shiners and for prawns that received supplemental feed. Growth was significantly higher (P < 0.05) for shiners grown with fed prawns than for shiners grown with unfed prawns. Shiner survival averaged 33% and was significantly higher (P < 0.05) in monoculture than in polyculture. Yield for all ponds averaged 392 kg/ha, with no significant differences between treatments (P > 0.05).     

Response to Selection and Realized Heritability for Length in Golden Shiner,Notemigonus crysoleucas

One generation of individual selection for increased total length in golden shiner, Notemigonus crysoleucas, at the 30th percentile (i = 1.159) increased average length from 109.4 mm in the F₁ control generation to 119.2 mm in the F₁ select generation; the difference was significant (P = 0.1). When means were adjusted by covariance analysis for number of fish at harvest, mean lengths were 111.0 mm for the F_l control generation and 116.9 mm for the F₁ select generation; the difference was not significant. Unadjusted and adjusted genetic gain was 10 mm (9.1%/generation) and 5.9 mm (5.3%/generation), respectively. Realized heritability using unadjusted and adjusted lengths was 0.70 and 0.42, respectively. These results suggest that selection can be used to improve growth rate and yield in golden shiner.     

Impact of Predation by Backswimmers in Golden Shiner,Notemigonus crysoleucas,Production Ponds

Laboratory and field studies were conducted to determine the population dynamics and potential for predation on golden shiner, Notemigonus crysoleucas, fry by the backswimmers, Notonecta indica and Buenoa scimitra. Both species were found to be highly effective predators under laboratory conditions. N. indica invaded newly flooded ponds within 2 weeks of putting spawning mats with eggs into the ponds and were thus present when fry were vulnerable to predation. B. scimitra invaded ponds at a slower pace and would not be as likely to cause extensive predation. N. indica had significantly lower (P = 0.05) population levels in ponds that had been established for one year. The potential loss from backswimmer predation could easily exceed 2.3 kg per 100 m of shoreline, assuming 40% of the fry lost to predation would survive to harvest. Diesel fuel treatment of backswimmer populations in 0.05-ha ponds resulted in about a 50% control of N. indica, mostly during the first 24 hours. B. scimitra were not as susceptible to the diesel fuel treatment. Several classes of insecticides were evaluated in the laboratory as potential control agents; Curacron, an organophosphate, and Cymbush a, synthetic pyrethoid, produced 100% mortality of N. indica at a concentration of 0.01 ppm. B. scimitra was even more sensitive to these compounds.     

Effect of Handling and Transport on Cortisol Response and Nutrient Mobilization of Golden Shiner,Notemigonus crysoleucas

As the most popular baitfish in the USA, the golden shiner is subjected to frequent handling and transportation episodes prior to retail marketing and recreational use. Considerable mortality and economic loss can occur during handling and transportation. Limited information is available concerning stress responses, such as cortisol secretion, and mobilization of nutrients, such as zinc and ascorbic acid, during handling and transportation of this fish species. Therefore, two concurrent experiments were performed to characterize cortisol responses, as well as changes in whole‐body zinc and visceral ascorbic acid concentrations, after harvesting, grading, and transporting by ground or air. During ground transportation, fish were sampled immediately after being subjected to the following conditions: seined from a commercial pond in Lonoke, Arkansas (I), released into vats from the loading truck (II), graded by bar grader (III), loaded onto a hauling truck (IV) and after transport for 10 h to Brenham, Texas (V). Fish were also sampled before and after air freight shipment. Whole‐body cortisol appeared to be a reliable endocrine marker for stress response of golden shiner subjected to handling and transportation. Grading by bar grader was the most stressful event in the process of handling and transporting golden shiners, resulting in a significantly elevated whole‐body cortisol concentration of 107 ng/g tissue, compared to concentrations of 6.3, 32.3, 15.7, and 30.4 ng/g tissue, for stages I, II, IV, and V, respectively. A significant increase in whole‐body cortisol concentration was also observed after air transportation of 22 h duration. No significant reductions in whole‐body zinc or visceral ascorbic acid concentrations were observed.     

Effect of Satiate or Restricted Feeding on Golden Shiner Notemigonus crysoleucas Production in Earthen Ponds

Abstract.— This study was conducted to evaluate the effects of satiate or restricted feeding on the growth and production of golden shiners Notemigonus crysoleucas . Golden shiners (1.2 g) stocked at 560 kg/ha in 12,0.04-ha earthen ponds for 79 d grew to average weights of 5.6, 4.6 and 3.8 g for fish fed to satiation, or 75% or 50% of that amount, respectively. Gross yield ranged from 811 to 1,277 kg/ha; net yield did not differ significantly among treatments.     

MS-222麻醉金鱼模拟运输试验

采用MS-222对金鱼实施麻醉并模拟运输试验,以减少金鱼代谢量,延长运输时间,提高长途运输的成活率,旨在探讨不同品种金鱼对MS-222麻醉的适宜浓度范围。结果表明,MS-222麻醉金鱼的适宜浓度范围为35-85mg／L,其具体使用浓度因金鱼的品种和运输密度不同而有一定的差异。     

鳜鱼生物学研究进展

鳜鱼是我国名贵淡水经济鱼类,本文通过对有关资料的归纳研究,对鳜鱼形态特征及比较分类、生态、食性与营养、年龄与生长、生理生化、遗传学、繁殖生物学等生物学研究现状进行综述,以期为其后继研究提供比较系统详实的基础资料。     

黑龙睛的繁殖及苗种培育技术

黑龙睛是金鱼的一个重要品种,非常富有特色.其体色黝黑,双眼圆臌,炯炯有神,尾呈蝶形,在水中游动时宛若仙子戏水,深得港台地区人士的喜爱.     

黑龙睛的繁殖及苗种培育技术

黑龙睛是金鱼的一个重要品种，非常富有特色。其体色黝黑，双眼圆臌，炯炯有神，尾呈蝶形，在水中游动时宛若仙子戏水，深得港台地区人士的喜爱。     

Responses of Juvenile Golden Shiner Notemigonus crysoleucas Fed Semipurified or Practical Diets With or Without Supplemental Ascorbic Acid

A 12-wk feeding trial was conducted in a flow-through system to determine whether juvenile golden shiner Notemigonus crysoleucas have a dietary requirement for ascorbic acid. Triplicate groups of 30 fish each weighing 0.44 g initially were fed semi-purified (casein) diets supplemented with 0 or 250 mg ascorbic acid/kg, or practical (fish meal) diets supplemented with 0 or 250 mg ascorbic acid/kg. The form of ascorbic acid used was L-ascorbyl-2-polyphosphate. Survival was higher in fish fed the semi-purified diet with 250 mg ascorbic acid/kg than in those fed the unsupplemented semi-purified diet, while weight gain did not differ between treatments. Weight gain was higher in fish fed the practical (fish meal) diet supplemented with 250 mg ascorbic acid/kg than in those fed the unsupplemented practical diet, while survival did not differ between treatments. No other signs of ascorbic acid deficiency were observed, but fish fed the casein diets had skin and fin erosion indicative of a possible bacterial infection. Whole-body concentrations of ascorbic acid (total, reduced, and percent of reduced ascorbic acid) were higher in fish fed semi-purified or practical diets supplemented with 250 mg ascorbic acid/kg than in fish fed unsupplemented diets. Golden shiners appear to require a dietary source of ascorbic acid for growth or survival, depending on experimental conditions. The two main differences in the study were in diet composition (semi-purified versus practical diets) and apparent health status of fish fed the different diet types. Additional studies are needed to define requirements further.     

Meristics and Morphometrics of Golden Shiner,Notemigonus crysoleucas,Rudd, Scardinus erythrophthalmus,and Their Reciprocal F1 Hybrids

Rudd, Scardinus erythrophthalmus, a European minnow, has been hybridized with golden shiner, Notemigonus crysoleucas, in an attempt to produce sterile hybrids. If these hybrids are to be used as bait, easy means of differentiating the parental species and their hybrids is needed to ensure that no rudd are being sold. The scale pattern along the keel is the easiest and quickest way to distinguish the two species and their hybrids: the keel is raised and scaleless in the golden shiner, and it has 6-9 scales in the rudd; in hybrids, the keel is scaled, but the scales have different shapes and insertions than those in the rudd. No other phenotype can be used to positively identify these groups. No phenotype can be used to separate the reciprocal hybrids.     

鱼类健康养殖方法探讨

随着人们生活水平的提高,消费者不仅满足于水产品数量的增加,对水产品质量要求也越来越高,鱼的鲜、活度、肉质、药物残留等成为消费者关注的话题。如何为消费者提供优质、丰富的水产品,寻求并开展鱼类健康养殖,是水产养殖生产者最重视的问题,也是今后水产养殖发展的方向。实现水产品健康养殖,关键要坚持科学管理,规范化操作,全程实施质量安全监测。1选育优良的养殖品种水质是水产健康养殖的物质基础,是基本的生产资料。优良的养殖品种有较强的抗病害和抵御不良环境的能力,不仅能降低养殖风险,增加养殖效益,同时也可避免因鱼病频发,大量用药…