温杖子水库网箱养殖罗非鱼试验

放养量４．５－６ｋｇ／ｍ＾３，饲养期约１００天，单产２７．０－３２．６ｋｇ／ｍ＾３，饵料系数１．３－１．７５，成本利润率５６．９％－７５．２％，能量转换率１７．９％－２３．９％。试验表明在我国北方网箱养非鱼能取得较高的经济效益。     

四合当水库网箱养殖武昌鱼试验

放养４．５－６ｋｇ／ｍ＾３，饲养期约１００天，单产２７－３２．６ｋｇ／ｍ＾２，饲养系数１．３－１．７５，成本利润５６．９％－７５．２％，能量转换率１７．９％－２３．９％，试验表明在我国北方网箱养武昌鱼能取得较高的经济效益。     

黑鲷幼鱼对饵料蛋白质,脂肪,糖类需求量的研究

实验了９种人工配合饵料，其中，蛋白质，脂肪和糖类含量为４１．２％，１７．６％和１５．９％的４号饵料，使黑鲷幼鱼生长最快，实验４３天，幼鱼增重率为６４．３％，饵料系数为１．３。     

鱼用中草药及添加剂配方与应用

１鱼用中草药４种１．１松针即松树的针叶，以腊月采集为最好。晾干、粉碎、混饲料用。松针粉含粗蛋白６．１４％～１２．１％、粗脂肪７．０６％～１１．４９％、微量元素、维生素、激素以及杀菌素等。胡萝卜素含量极其丰富，高达１９７～３４４ｍｇ／ｋｇ。在鱼饵料中添加４％松针粉进行网箱养鱼试验，结果添加松针粉的试验组与对照组相比，净产提高４．２８％，个体生产提高１０．４７％，商品鱼规格提高９．７７％。１．２大蒜大蒜味辛、性温。有行气暖胃、解毒、杀菌、杀虫等功效。在饲料中添加１％大蒜渣预混剂，鱼的成活率提高１５％…     

蓝鳃太阳鱼的饵料配方

蓝鳃太阳鱼的饵料配方蓝鳃太阳鱼是美国养殖的主要游钓鱼类。试验证明饵料蛋白含量为２５％，可使太阳鱼获得最佳生长速度。饵料配方如下；鱼粉６．５％，豆粉３４％，玉米５２％，鲤鱼肝油１．５％，维生素无机盐预混物１％，磷酸一钙１％，粘合剂州。Ｉｋｇ预混料含维生...     

网箱中鳜鱼摄食行为的初步观察

对网箱中鳜摄食行为的初步观察结果表明：网箱中的鳜会争食、集群捕食活铒并能主动吞食死饵；摄食高峰在傍晚和拂晓；活饵（鳙、鲢）具有对鳜的防御性行为反应；７－８月鳜日粮、日增重随个体生长而分别增加１１．２倍和６．１倍，饵料系数２．０４－４．０５；饵料鱼（鲢）体长为鳜的体长的４２．３％－５７．８％，平均为５０．６％。     

北民湖自然资源的调查及渔业开发初探

１９９０年，调查了北民湖（１４６７ｈｍ２）的水质，水生生物等情况，该湖氮、磷营养缺乏（ＴＮ１．１８３０ｍｇ／ｌ，ＴＰ０．０２０１５ｍｇ／ｌ），ＴＮ∶ＴＰ＝５８．７１∶１，为浮游生物生长限制因子，折算产鱼潜力为３１．６２ｋｇ／ｈｍ２，通过人工定点施化肥，使其ＴＮ，ＴＰ达到２．０５８４ｍｇ／ｌ，０．２１４５ｍｇ／ｌ，ＴＮ∶ＴＰ＝９．６∶１，投放鱼种３７．５ｋｇ／ｈｍ２，年产鱼２８４．０４ｔ，折合１９３．６ｋｇ／ｈｍ２，为１９８９年鱼产量２８．６４ｋｇ／ｈｍ２的６．７６０倍。     

中华绒螯蟹大面积半精养高产试验

使用１口面积为３．６ｈｍ＾２的池塘（５４亩）,进行中华绒螯蟹半精养试验。放养蟹种（扣蟹）密度为９１０８只／ｈｍ＾２（６０７只／亩）,个体均重１１ｇ／只,经１８０ｄ饲养,获得总产２７２７ｋｇ,平均７５７．５ｋｇ／ｈｍ＾２。增重９．３４倍;出塘率８１％,饵料系数１．０４。总产值１４９９８５元,总利润为５７７６３．１元。投资回报率１６２．６％。     

寒区沼泽地稻菇鱼养殖模式研究

为解决寒区沼泽地低温冷浆，不利于水稻生长的问题，“八五”攻关期间，在三江平原沼泽区采用垄稻沟鱼、稻行养蘑菇的形式，建立了稻、菇、鱼立体农业模式。１９９５年实产水稻５６１３．９ｋｇ／ｈｍ２，蘑菇６３０７．２ｋｇ／ｈｍ２，鱼１１３７．６ｋｇ／ｈｍ２，纯收入１０６４２．２元／ｈｍ２，投入产出比１∶１．８８。同时改善了沼泽土壤温度和养分状况。     

网箱养殖黄鳝的试验研究

本试验在池塘中进行，设置网箱２６０只，面积５５４０ｍ＾２。试验结果，鳝鱼总产量１６９８５．６ｋｇ，平均单产３．０７ｋｇ／ｍ＾２，平均规格０．２５ｋｇ／尾，成活率６０．７５％；饵料系数５．７５，增重倍数２．４５，投入产出比１：２．４８，单位面积盈利７３．２４元／ｍ＾２。     

Appropriate Timing of Supplemental Feeding for Production of Nile Tilapia, Silver Carp, and Common Carp in Fertilized Polyculture Ponds

In an attempt to identify appropriate times for initial application of supplemental feed in polyculture fertilized fish production earthen ponds, a study was conducted for 19 wk to establish the growth performance, yield, survival, and body composition of Nile tilapia, common carp, and silver carp as influenced by four different feeding regimens (treatments). The four treatments were: 1) supplemental feeding beginning at onset of the experiment (T-I) (control treatment); 2) 6-wk delay of feeding after fish stocking (T-II); 3) 13-wk delay of feeding after fish stocking (T-III), and 4) no supplemental feed application (T-IV). Two ponds were assigned to each treatment and each pond was stocked with a similar number and weight of each fish species. A commercial pelleted fish feed (25% protein) was used to feed fish in T-I, T-II, and T-III at 3% of their body weight, twice a day. At the end of the experiment, fish species (except for silver carp) in T-II showed weight gain, growth rates, and yields significantly higher than fish in T-III or T-IV. Also, the total fish production and net profit in T-II were significantly higher than in T-III or T-IV. Fish species in T-II showed weight gain, growth rates, survival rates, and yields similar to those of T-I (control treatment) with no significant differences. The amount of feed consumed by fish in T-II was reduced by approximately 7.3% compared to that consumed by fish at T-I. Moreover, there was increase in th net profit in T-II by 4.8% over that achieved in T-I. Therefore, T-II appears to be the most appropriate among the tested feeding treatments and recommended for use in order to achieve the best growth, production, and net profit.     

Use of Cottonseed Meal in Channel Catfish Feeds

Solvent extracted cottonseed meal was substituted for soybean meal in catfish feeds on a nitrogen basis. The feeds, which contained either 0, 10, or 20% cottonseed meal, were formulated to contain about 32% protein and 2.9 kcal digestible energy/g. The fish were reared in 6 m³ net pens suspended in a 1.6 ha earthen pond. Twelve pens (four per treatment) were stocked with 400 fish with an initial average weight of 95 g/fish. All fish were fed to satiation once daily. A sample of 60 fish from each pen was weighed at 76 days to evaluate feed consumption, feed conversion, and weight gain. At the end of the experiment (132 days), fish from each net pen were weighed collectively and samples were taken to determine tissue free gossypol concentrations, proximate composition of fillets, and dressout percentages. There were no significant differences in weight gain, feed conversion, or survival of fish sampled at 76 days or of fish at the end of the experiment regardless of dietary treatment. At 76 days, feed consumption of fish fed the 20% cottonseed meal feed was significantly higher than that of other fish, but there were no significant differences in feed consumption at the end of the experiment. Free gossypol levels were below detectable limits in fish tissue. There were no significant differences in percentage dressout or in body composition, except for a slightly higher ash content in fish fed the feed containing 10% cottonseed meal. It appears that cottonseed meal can be used to partially substitute for soybean meal in catfish feeds. At the present, it is recommended that cottonseed meal be limited to 15% of the catfish diet.     

Effects of water flow velocity and fish culture on net biofouling in fish cages

The effects of water flow, fish feed and cage position on net biofouling was examined in a floating cage fish farm. Fouling of 16 mm mesh net panels suspended inside and outside net cages and exposed to different treatments were monitored weekly until net apertures were completely occluded by the fouling organisms (8 weeks). Results indicate a dramatic reduction in water flow velocity throughout the fish farm due to the cage units themselves and net biofouling. The reduced water flow (<10 cm s^?1) inside net cages promoted rapid net biofouling, while rapid water flow outside the net cages (>25 cm s^?1) kept the net fouling organisms at bay. Although fish rearing in net cages with inputs of commercial pellet feed increased sessile biofouling (222% higher than outside the net cages) and non‐sessile biofouling (570% higher), the type of fish feed used did not significantly affect biofouling development. The study recommends that the geometry of serially arranged net cages, as commonly deployed in tropical tidal estuaries, be reconfigured to improve flow through in order to minimize the impact of fouling.     

Effects of supplementary feeds with different protein levels on growth and economic performances of Nile tilapia (Oreochromis niloticus) cultured in a rain-fed rice–fish ecosystem

This study investigated the effects of supplementary feeds with different crude protein (CP) levels on the growth and economic performances of sex-reversed Nile tilapia (Oreochromis niloticus) reared in a rain-fed rice–fish ecosystem for a period of 120 days. There were four treatments—namely, traditional feed (21% CP), formulated feed (26% CP), commercial feed (30% CP), and control (no feed was used)—with three replicates per treatment. Fish (30.04 g) were stocked in ditches at a rate of 0.5 fish m^?2 considering the total area and fed one of the tested feeds twice daily at the rate of 2%–5% of body weight. Water-quality parameters of the ditches were monitored fortnightly, and these parameters were found suitable for fish farming. Organic matter, total nitrogen, and available phosphorous in soil were increased significantly (P < 0.05) in the feed treatments after fish cultivation. Highly significant weight gain and SGR were observed with fish fed the commercial feed as compared with other treatments. The highest benefit-cost ratio (2.15) was found in the control, followed by formulated feed (1.90), but in the case of numerical net return, it was the opposite. However, commercial feed showed the lowest benefit-cost ratio (1.67) due to higher feed cost than other supplementary feeds. Therefore, this study suggests that fish fed with a formulated feed (26% CP) produced significantly higher net economic return in the rice–fish farming system.     

Evaluation of potential feed sources,and technical and economic considerations of small‐scale commercial striped catfish (Pangasius hypothalamus) pond farming systems in the Mekong Delta of Vietnam

A technical and socio‐economic survey was conducted in Dong Thap, Can Tho and An Giang, provinces of Vietnam in 2009. The results showed that most of the small scale farmers of striped catfish (Pangasius hypothalamus) carry out fish pond culture, developed and operated by self‐learned experience and from neighbours knowledge. The mean pond depth varied from 3.5 to 4.0 m, ranging from 2 to 6 m. Most of the fish farms have extremely high stocking density, with an average of about 40 fish m^?2, in some cases up to 70 fish per m². The average yields and net income of small‐scales pond farming is about 21–27 kg per m² crop^?1 and US$ 0.184–0.329 kg^?1 crop^?1 respectively. These figures are not significantly different compared with large‐scale pond farming. About 75%, 86% and 80% of fish farmers in Dong Thap, Can Tho and An Giang province, respectively, received positive net returns. Farm‐made feed is still playing an important role because of higher net profit compared with commercial pellet feeds. Rice bran and trash fish are the main feed ingredients for farm‐made feed formulations. Striped catfish farmers are now actively searching for locally produced plant protein sources as alternatives to marine trash fish or fish meal.     

Supplementation of various meals to fish meal diet for chum salmon fry

In a 6-week feeding experiment, chum salmon, Oncorhynchus keta, swim-up fry, were fed fish meal diets supplemented with silkworm pupae powder (5%), dried beef liver (5%), krill meal (5%) or earthworm powder (5%) at the expense of fish meal, or substituting glucose (13%) for dextrin. Fish fed the diet with earthworm powder showed the best growth performance (675% weight gain in 6 weeks) and feed efficiency (117%). The growth rate and feed efficiency of the krill meal group were also significantly better than those of the control group (without supplement or substitution). Substitution of glucose and supplementation of silkworm pupae or beef liver failed to improve the growth rate, but significantly improved feed efficiency. Food consumption of fish fed the diet supplemented with earthworms was lowest, and none of the dietary treatments appreciably increased food intake of the fish over that of the control group. The dietary group receiving earthworm powder also showed significantly higher body fat content than the remaining dietary groups. No significant differences were noted in body protein and ash contents among all dietary treatments.     

Growth, feed utilization and nutrient digestibility in tilapia fingerlings (Oreochromis aureus Steindachner) fed diets containing bacteria-treated coffee pulp

The effectiveness of bacteria treated‐coffee pulp (BT‐CoP) in fish diets was evaluated in a feeding trial with Oreochromis aureus (Steindachner) fingerlings. Five diets were formulated to contain 0%, 6%, 12%, 18% and 24% BT‐CoP, replacing wheat meal. Fish were reared in a recirculating unit consisting of 16 aquaria. Each aquarium was stocked with 10 fish of 1.1–2.4 g. Fish were fed ad libitum twice daily (10 and 15 h) for 4 weeks. Fish fed diets without BT‐CoP and with 6% BT‐CoP showed similar growth (body weight, growth rate: RGR_m) and feed utilization (feed conversion ratio, protein efficiency ratio, apparent net protein utilization). Diets containing 0% and 6% BT‐CoP gave similar dry matter and protein digestibility coefficients, but dietary BT‐CoP levels higher than 6% produced lower digestibility values, except for carbohydrate. It is concluded that O. aureus fingerlings may assimilate only small amounts (6%) of BT‐CoP in the diets without adverse effects on growth and feed utilization parameters. The CoP‐containing diets did not affect fish survival (100%). The depression in tilapia performance may be associated mainly with the high level of fibre present in the CoP diets.     

Integrated Duck-cum-Fish Farming in Bangladesh

An experiment on integrated duck-cum-fish farming was conducted in 11 ponds of 0.1 ha each at the Fisheries Research Institute, Mymensingh, Bangladesh. Khaki Campbell layer ducks Anas platyrhychos were housed directly over the pond water surface at 200, 400 and 500 dncks/ha. Each density had three replicate ponds and two ponds had no ducks. Fish fingerlings were stocked at a total density of 8,850/ha. The species composition was silver carp Hypophthalmicthys molitrix 33.9%; catla Catla catla 12.4%; rohu Labeo rohita 18.1%; mrigal Cirrhina mrigala 28.8%. grass carp Ctenopharyngodon idella 1.4% and sor puti Puntius gonlonotus 5.4%. The fish were not given any supplemental feed, and the ponds were not fertilized except for the split duck feed and duck manure falling directly into the ponds. Ducks were fed with a feed formulated from locally available ingredients.
After one year the fish were harvested. The yield of fish increased with an increase in duck density. Highest net fish production of 4,250 kg/ha/yr was obtained from ponds with 500 ducks/ ha, compared to 490 kg/ha/yr from the control ponds. Manure of each duck contributed a net fish yield of 6.9–7.5/yr. Average egg production was 237 eggs per female duck per year. Economic analysis of the technology showed a net profit of about 100% of the total costs, indicating the economic viability of the technology.     

Comparative growth and yield of channel catfish and channel × blue hybrid catfish fed a full or restricted ration

Growth and yield (kg ha^?1) of the channel catfish (Ictalurus punctatus, Rafinesque, 1818) and the channel × blue hybrid catfish [I. punctatus female ×I. furcatus (Lesueur, 1840) male], which shared the Jubilee strain of channel catfish as the maternal parent, were compared in sixteen 0.1 ha earthen ponds (14 852 fish ha^?1) during the April to November growing season. Each fish genetic group was fed a commercially formulated 32% protein feed daily to apparent satiation or at 80% of the mean daily satiation ration. Net yield and individual weight were higher for channel × blue hybrid catfish compared with channel catfish and for fish fed a full ration compared with a restricted ration. When fed a full ration, the channel × blue hybrid catfish grew faster from May to September than did the purebred channel catfish because the hybrid catfish consumed a greater percentage of its body weight at each feeding. Net yield within each fish genetic group was lower when feed ration was restricted. The per cent reduction in net yield in response to feed restriction was similar for each fish genetic group.     

Influence of dietary oil content on the growth and chemical composition of Atlantic salmon (Salmo salar)

Two extruded diets with oil/protein levels of 260/410 and 360/365 g kg^?1 were used to feed Atlantic salmon, from an initial weight of 600 g to a final weight of 4 kg after 1 year of feeding. The experiment was performed using 12 net‐pens with 500 fish in each. Every 4 months 10 fish were taken from each net‐pen, and analysed for growth and proximate composition. After 4 months of feeding, the chemical composition in the fillets was significantly different for the two different feed groups. The mean fillet fat content was 1% higher in fish fed with high oil content in the feed. There were no differences in the biological values. After 8 months of feeding the difference in mean muscular fat content was 3%, but there was still no difference in the carcass weight. However, a significant difference was found in the intestine weight and the condition factor. One year of feeding resulted in a significant, 10% higher carcass weight, a 2% higher fat‐content and a 1% lower protein‐content in the fillets of fish fed on the high oil content diet. A drop in pH was found during the winter, but this was not correlated to the feed.