四种饲草新品种的栽培及渔业利用

<正> 利用人工种植的饲草养鱼,以草换鱼,是我国传统的养殖方式,也是降低养鱼生产成本提高经济效益的重要途径。近年来,渔用饲草品种除了苏丹草、黑麦草等常见品种外,又陆续引进、开发了几种渔用饲草新品种。本人通过对有关资料的归纳研究,结合自己的实践,对四种饲草新品种的生物学特性、栽培方法及渔业利用技术试作简要概述如下:     

几种渔用饲草新品种的生物学特性及栽培利用技术

利用人工种植的饲草养鱼,是我国传统的养殖方式,也是降低养鱼生产成本提高经济效益的重要途径。近年来,渔用饲草品种除了苏丹草、黑麦草、紫花、苜蓿等常见品种外,又陆续引进、开发了几种渔用饲草新品种。本文通过对有关资料的归纳研究,概     

饲草青贮技术优化措施探讨

饲草青贮技术能良好的保存新鲜饲料,提升饲草使用价值,增强饲草利用效率。阐释了推广饲草青贮的意义和作用。认为要从转变饲草青贮发展模式、提升饲草青贮质量标准、加大技术人员培训力度和优化饲草青贮设施等方面提升青饲草推广利用效率,推动畜牧业高质量发展。     

一种新的杂交饲草

一种新的杂交饲草杂种优势是一种普遍的生物学现象，为了提高饲草的单位面积产量，改进饲草的品质和增强苏丹草的抗病性，美国、独联体、澳大利亚和日本等国都已选育了高梁ＡＸ苏丹草杂交种（以下简称杂交苏丹草）在生产上应用。我们于１９８２年起也进行了这方面的选育工...     

几种渔用饲草新品种的生物学特性及栽培利用技术

利用人工种植的饲草养鱼,是我国传统的养殖方式,也是降低养鱼生产成本提高经济效益的重要途径。近年来,渔用饲草品种除了苏丹草、黑麦草、紫花苜蓿等常见品种外,又陆续引进、开发了几十种渔用饲草新品种。本文通过对有关资料的归纳总结,概述几种渔用饲草新品种的生物学特性、栽培方法和渔业利用技术。1摩特矮象草1.1生物学特性摩特矮象草是1987年从美国引进的禾本科饲草,多年生,茎丛矮,一般株高80～140厘米,节短而多,株含叶量大,冠幅70厘米以上,株叶量可占株重80%以上,分蘖再生能力强。茎丛生、直立、圆形,直径1～2厘米;叶长40～80厘米,宽2…     

优良鱼类饲料──扁穗牛鞭草

优良鱼类饲料──扁穗牛鞭草扁穗牛鞭草是一种多年生禾本科饲草，具有生长快、产量高、适应性强、抗逆性好等特点，深受养殖户欢迎。现在湖北、湖南、四川等省开始大面积推广运用。实践证明，这是一种很有发展前途的优良饲草。一、特征与特性扁穗牛鞭草有长根状茎，杆高１...     

铜川市饲草种植情况调研

组织技术人员通过电话咨询、实地调查等多种形式,对铜川市的耀州区、新区、王益区、印台区、宜君县等饲草种植情况进行了实地调查研究,较为全面地掌握了铜川市饲草产业发展情况,就发现存在的问题,提出相关建议措施。     

多途径解决网箱养鱼饲料办法

一、种草养鱼,发展草食型网箱草食型网箱以其广泛的适应性和明显的经济效益而得到迅速发展和普及。但是,随着其发展数量的不断增加,靠打草喂鱼、有啥喂啥、靠天养鱼的传统粗放养殖方式已远不能满足网箱养鱼的发展需求。因此,对于在湖泊、水库、河流进行网箱养鱼,应充分利用岸边空坪隙地扩种产量高、适应性广的优质饲草,如黑     

六种渔用饲草新品种的栽培及利用

利用人工种植的饲草养鱼，以草换鱼，是我国传统的养殖方式，也是降低养鱼生产成本提高经济效益的重要途径。近年来，除了苏丹草、黑麦草、苦荬菜、紫花苜蓿、聚合草、三叶草等常见品种外，又逐渐引进、开发了几种渔用饲料草新品种。本文作者通过对有关资料的归纳研究，结合自己的实践，对六种渔用饲草新品种的生物学特性、栽培方法及利用技术进行初步探讨。     

高产优质饲草——皇草

高产优质饲草──皇草皇草（Ｋｉｎｇｇｒａｓｓ）是一种禾本科狼尾草，属多年生高产优质饲草品种，是由象草和美洲狼尾草（又名珍珠草〕杂交育成。１９８２年海南热作院从哥伦比亚引进试种成功以后，先后有两广，江西、湖南等省（区）进行引种都获得了成功。根据我所及海...     

Brandt's cormorant diet (1994–2012) indicates the importance of fall ocean conditions for northern anchovy in central California

Effective ecosystem‐based management requires a comprehensive understanding of the functional links in the system. In many marine systems, forage species constitute a critical link between primary production and upper trophic level marine predators. As top predators, seabirds can be indicators of the forage species they consume and the ocean processes that influence these populations. We analyzed the diet and breeding success for the years 1994, 2003, 2005, and 2007–2012 of the Brandt's cormorant (Phalacrocorax penicillatus), a piscivorous diving seabird, breeding in central California, to evaluate the extent to which cormorant diet composition relates to prey availability, and how diet composition relates to breeding success and ocean conditions. Cormorant diet was primarily composed of young‐of‐the‐year (YOY) northern anchovy (Engraulis mordax), YOY rockfish (Sebastes spp.), and several species of small flatfish (order Pleuronectiformes). YOY rockfish consumption was positively related to their abundance as measured in a late spring pelagic midwater trawl survey. Northern anchovy appeared to be the most important prey as its consumption was positively related to cormorant breeding success. More northern anchovy were consumed in years where warm‐water conditions prevailed in the fall season before cormorant breeding. Thus, warm ocean conditions in the fall appear to be an important contributing factor in producing a strong year‐class of northern anchovy in central California and consequently a strong‐year class of Brandt's cormorant on the Farallon Islands.     

Substitution of Balanced Feed with Chaya,Cnidoscolus chayamansa,Leaf in Tilapia Culture: A Bioeconomic Evaluation

The main challenge for tilapia culture in rural areas of Mexico is low producer income and difficulty in acquiring inputs (fingerlings and balanced feed). In response, some rural producers feed tilapia with locally available vegetal inputs such as chaya, Cnidoscolus chayamansa. This plant is a bush endemic to the Yucatan Peninsula, Mexico, that is traditionally used for human and animal nutrition. In these rural culture systems, chaya is provided ad libitum as fresh leaves. Its use to date is empirical, and therefore, little is known about optimum substitution levels. A bioeconomic model was developed using experimental data. The von Bertalanffy model was parameterized using chaya/balanced feed combinations that produced growth not statistically different than a diet with sole use of balanced feed. This model included biological, economic, and management components. The results indicate that balanced feed can be substituted by chaya leaves at up to 50% and that this substitution level provides the lowest production costs during the warm season. Maintenance of this production level requires 2.23 units of chaya per unit of balanced feed, with the restriction that only 50% of the ration can be substituted by chaya leaves.     

Effect of partial or total replacement of forage fish by a dry diet on the quality of reproduction in pikeperch, Sander lucioperca

The aim of this preliminary study was to evaluate the influence of different feeding regimes on the quality of reproduction in pikeperch. Three diets were tested: forage fish (FF), a commercial dry feed (DD) and a mix of both (FD).  The diets were given to fish throughout a complete reproductive cycle. During the spawning season, couples were injected with human chorionic gonadotropin (hCG) and let to spawn on nests. Proportion of running males, spawning and hatching success and larval quality (weight, length, body protein, total lipid, fatty acid and lipid class compositions and resistances to osmotic shock and starvation stress tests at hatching) were evaluated. The proportion of running male was lower in the DD group than in the FF and FD groups (54% for DD against 76–89% for FF and FD). In addition, 25%, 62.5% and 75% of injected couples gave spawning that hatched in DD, FF and FD groups respectively. Larval quality parameters were not significantly different between treatments. The results indicate that overall quality of reproduction was higher in FF and FD treatments than in DD. It suggests that the dry feed used was not totally adequate for pikeperch reproduction. Relations between breeder reproductive performances and the feed compositions are discussed.     

Passing times of two types of feeds in wels (Silurus glanis) at three different temperatures

Passing times of two different types of feeds were determined in cases of wels (Silurus glanis) by measuring the body weight at three different temperatures. Fingerlings, 38.03 ± 8.04 g, were fed by an artificial dry feed (commercial catfish feed) or forage fish. The treatments were carried out (11 fish/aquaria) in 3 replicates. Fish were individually tagged by pit tags. Temperatures applied were the following: 15, 20 and 24 °C. The appetite of fish highly depended on temperature. At 15 °C, only 42.4 % of the experimental fish accepted the granulated feed, while this ratio was 90.9 % in the forage fish fed group. At higher temperatures, 100 % of the experimental fish accepted feed in both feeding groups. The daily mean value of consumed feed at 15 °C was 3.20 % of body weight in the case of forage fish and 1.36 % in the case of dry feed. At 24 °C, this ratio was 10.68 % of body weight in cases of forage fish and 4.46 % in cases of artificial feed. At low temperature (15 °C), the quantity of consumed feed met the measurement’s error threshold, which made the determination of passing time uncertain. At 20 °C, the evacuation started 20 h after feeding and lasted for 18 h, while at 24 °C, it started 11 h after feeding and lasted for another 16 h.     

Channel Catfish Polyculture with Fathead Minnows or Threadfin Shad: Effects on Pond Plankton Communities and Catfish Fillet Flavor,Color, and Fatty Acid Composition

Threadfin shad, Dorosoma petenense, or fathead minnows, Pimephales promelas, were co‐cultured with channel catfish, Ictalurus punctatus, in earthen ponds to determine the effects of planktivory on plankton community dynamics and catfish fillet quality. Fathead minnows had no effect on the plankton community structure or catfish fillet flavor, color, and fatty acid composition. Fillet color was also unaffected by the presence of threadfin shad. Small differences were found in fillet fatty acid composition for catfish from ponds with shad, but these differences probably have no biological significance. Threadfin shad did, however, have important impacts on the plankton community structure and catfish flavor. Size‐selective filter‐feeding by shad reduced cyanobacterial abundance relative to ponds with catfish‐only and fathead minnows. Relative abundance of smaller phytoplankton in the groups Chlorophyta, Cryptophyta, Bacillariophyceae, and Euglenophyta increased in ponds with shad. Relative abundance of small zooplankton (rotifers) also increased in shad ponds. Reduced abundance of large, colonial cyanobacteria that are known to produce odorous metabolites caused a corresponding reduction in off‐flavor prevalence and intensity in catfish from ponds with threadfin shad when sampled in September. Although threadfin shad dramatically reduced catfish off‐flavor prevalence during the warm season, they apparently caused a high prevalence of “fishy” off‐flavors in the February sample. This undesirable flavor appeared to be caused by catfish foraging on shad killed during a preceding period of exceptionally cold water temperatures. Use of threadfin shad for phytoplankton biomanipulation therefore presents a dilemma: catfish–shad polyculture reduces prevalence of cyanobacteria‐related off‐flavors in warm months but may cause undesirable forage‐related off‐flavors in the colder months. Catfish farmers must consider these benefits and risks when deciding to use threadfin shad as a management tool.     

Temporal patterns in the post-larval supply of two crustacean taxa in Rangiroa Atoll,French Polynesia

The post-larval supply of two crustacean taxa (Brachyura and Stomatopoda) was monitored using one crest net over three lunar months at Rangiroa Atoll, French Polynesia. We captured a total of 37,068 brachyuran and 12,697 stomatopod post-larvae during the study. Post-larval supply was higher during the warm season (February–April) than during the cold season (June–July) for both Brachyura (warm season: 85% of total post-larval supply) and Stomatopoda (warm season: 92%). Moreover, the pulse of the brachyuran post-larval supply occurred predominantly around the last quarter, while the pulse of stomatopods occurred predominantly around the new moon. However, for both taxa, the post-larval supply was lowest around the full moon and the first quarter. Overall, our monitoring highlighted that the post-larval supply of Brachyura and Stomatopoda was modulated by seasons and lunar phases at Rangiroa.     

基于稳定同位素的草鱼推水养殖系统食物网的研究

推水养殖系统是集循环养殖、高效集污、生物净化及自动控制等技术为一体的生产方式。但该系统营养物质归趋尚未明晰,造成饵料资源浪费和养殖调控失策。该研究以草鱼(Ctenopharyngodon idellus)推水养殖系统为实验组,以普通池塘养殖系统为对照组,利用稳定同位素[碳(δ13C)、氮(δ15N)]技术研究两种养殖系统生物食物组成和系统食物网结构。结果表明,草鱼推水养殖系统各生物组分δ13C介于(-25.76±0.23)‰^-22.26±0.20‰,普通池塘系统δ13C介于(-25.83±0.24)‰^-22.38±0.15‰;推水养殖系统各生物组分δ15N介于(6.73±0.08)‰^12.34±0.11‰,普通池塘系统δ15N介于(6.73±0.08)‰^12.14±0.11‰。稳定同位素混合模型分析结果显示,两组系统中草鱼饲料和底泥碎屑是消费者的主要食物来源。其中,草鱼的主要食物来源是草鱼饲料,鳙(Aristichthys nobilis)的主要食物来源是草鱼饲料、大型浮游动物,鲫(Carassius auratus)的主要食物来源是底泥碎屑,底泥碎屑的主要来源是草鱼饲料。推水养殖系统草鱼饲料对草鱼的食物组成贡献率高于普通池塘系统。因此,采用推水养殖模式,可促进养殖生物对饲料的摄食,提高饲料利用效率。     

饵料类型和投喂频率对鳡幼鱼生长及肌肉成分的影响

研究了不同养殖模式F1(投喂1次饵料鱼/d)、F2(投喂2次饵料鱼/d)、A1(投喂1次人工配合饲料/d)、A2(投喂2次人工配合饲料/d)对鳡(Elopichthys bambusa)幼鱼生长及肌肉成分的影响,实验持续56 d.结果显示:各组最终体重为A2 ＞F2 ＞A1 ＞F1.饵料相同时,2次/d组生长速度、肌肉...     

Evaluation of the Economics of Multi-Batch Channel Catfish Ictalurus punctatus Production Fed an Industry Standard and Three Alternative Diets

The purpose of this study was to determine the feasibility of growing marketable channel catfish, Ictalurus punctatus, from pond-run fingerlings (15.9 g/fish) using low stocking densities (7,413 or 14,826 fish/ha) and electrified bug lights to enhance natural forage available to fish. Even at low stocking densities, fish only averaged 0.2 kg at the end of the growing season. Because marketable sizes of fish were not reached over the growing season, stocking small fingerlings at these rates would not be practical under most commercial production scenarios. Nutritionally, captured insects from electrified bug lights were near a complete diet for catfish, but bug lights did not capture sufficient quantities of insects to affect fish production in either stocking density. Stocking small fingerlings at low stocking rates does not produce market‐sized catfish during one growing season; commercially available bug lights did not provide adequate amounts of natural forage to affect production variables.     

乳山近海渔业资源种类组成及变化

根据2013—2015年乳山近海拖网渔船的渔捞日志,分析了乳山近海的单位捕捞努力量渔获量、渔获种类组成及生物多样性等特征。结果表明:(1)乳山近海渔获物共有36种,隶属于19目28科33属。其中鱼类有26种,虾蟹类4种,头足类4种,水母类1种,贝类1种。(2)2013—2015年全年优势种差异明显。其中,蓝点马鲛3年均为优势种,鳀鱼是2014年和2015年优势种,网纹狮子鱼为2013年和2015年的优势种。(3)乳山近海渔获物主要集中在休渔期前后的4—5月、9—11月,渔业生产存在明显的春汛和秋汛。2013—2015年乳山近海单位捕捞努力量渔获量逐年增加,但与历史单位捕捞努力量渔获量相比还是存在明显下降;多样性指数和均匀度指数变化趋势一致,多样性指数和丰富度指数较高值出现在秋季;春汛和秋汛期间,渔业资源种属组成及群落结构相似性较高。