不同单养和混养海水实验围隔初级生产力的研究

１９９５年和１９９６年夏秋季进行的围隔实验表明投饵养殖时浮游植物毛初级生产力较低,水呼吸相对较高,多数围隔中毛初级生产力／水呼吸〈１,其中混养中国对虾和台湾红罗非鱼的围隔中毛初级生产力较高,而混养中国对虾,台湾红罗非鱼和菲律宾蛤仔的围隔中毛初级生产力最低;在投饵基础上酌情施肥后围隔毛初级生产力同于投饵养殖时,毛初级生产力／水呼吸〉１,但单养中国对虾,对虾与罗非鱼混养和对虾与海湾扇贝或缢蛏混养的围隔     

不同单养及混养海水实验围隔水化学的研究

１９９５年６～１０月和１９９６年６～８月对不同单养和混养海水实验围隔的水化学研究结果表明：围隔中盐度、总氮、总磷和化学耗氧量（ＣＯＤ）在雨季前逐渐升高,进入雨季后降低;投饵养殖时围隔中磷浓度较低氮浓度较高,其中混养中国对虾和台湾红罗非鱼的围隔活性磷（ＰＯ４－Ｐ）浓度相对较高,混养对虾与菲律宾蛤仔的围隔氨氮（ＮＨ３－Ｎ）浓度较高,投铒兼酌情施肥养殖时围隔中氮浓度较低磷浓度较高,其中混养中国对虾与缢蛏     

Experimental studies on intensive polyculture of Chinese shrimp with bay scallop

用放在海水池塘中的８个陆基围隔（５０ｍ×５０ｍ×１８ｍ），研究中国对虾（Ｐｅｎａｅｕｓｃｈｉｎｅｎｓｉｓ）与不同密度海湾扇贝（Ａｒｇｏｐｅｃｔｅｎｉｒａｄｉａｎｓ）投饵混养的放养方式、生产力和极限放养量。对虾体长（２８５±０１６）ｃｍ，扇贝壳长（１１０±０１２）ｃｍ，放养密度分别为６０尾／ｍ２和０，１５，４５，７５粒／ｍ２，用投饵和施肥（鸡粪和化肥）饲养。结果表明，扇贝密度为０和１５粒／ｍ２时，对虾的成活率无显著差异。混养（扇贝１５粒／ｍ２）时对虾的出塘体长、体重和产量分别比单养高２５％，３８％和６５％；当扇贝密度高于１５粒／ｍ２时，对虾的平均体长、体重和产量随扇贝密度的增加而显著减少（Ｐ＜００５）。扇贝密度为１５和７５粒／ｍ２时，其产量由４７０ｋｇ／ｈｍ２增至１２３６ｋｇ／ｈｍ２；当扇贝密度高时，去壳后湿重占体重的百分数从（４２８４±３４４）％降至（３７８８±４２６）％。扇贝的极限放养量为６００～８００ｋｇ／ｈｍ２，适宜放养密度为１０～１５粒／ｍ２。     

对虾养殖实验围隔中的固氮作用及其氮输入

１９９７年６～１０月,以乙炔还原法进行了不同放养模式下对虾养殖实验中生物固氮作用的测定。结果表明,各围隔中,对虾单养（Ｙ－４）和对虾＋海湾扇贝（Ｙ－５）的固氮作用较高,均值分别为２．６２μｇＮ／（Ｌ·ｈｒ）和２．６５μｇＮ／（Ｌ·ｈｒ）;对虾＋罗非鱼＋缢蛏（Ｔ－５）的最低,为１．５３μｇＮ／（Ｌ·ｈｒ）,对虾＋缢蛏（Ｙ－６）和对虾＋罗非鱼（Ｙ－７）的分别为２．３０μｇＮ／（Ｌ·ｈｒ）和１．８９μｇＮ／（Ｌ·ｈｒ）。各围隔中固氮速率较高与水体有效氮含量较低及有效氮磷比值不高有关。水层固氮蓝藻主要为蓝球藻（Ｃｈｒｏｃｏｃｕｓ）和念珠藻（Ｎｏｓｔｏｃ）。估算各围隔实验期间固氮作用输入分别为Ｙ－４∶１７．７２ｇ;Ｙ－５∶１９．６３ｇ;Ｙ－６∶９．０５ｇ;Ｙ－７∶１０．５９ｇ;Ｔ－５∶７．９９ｇ。     

不同单养的混养海水实验围隔浮游生物的研究

１９９５年６～１０月和１９９６年６～８月对中国对虾养及其与台湾红非鲫、菲律宾蛤仔、海湾扇贝或缢蛏的不同混养实验围隔浮游生物的研究结果表明,养管理措施和放养种类对围隔浮游生物种类和生物量都会产生一定影响,其中前者往往具主要作用。投饵养殖时围隔浮游植物以２０μｍ以下的种类为主,生物量较低,其中混养台湾红非鲫的围隔叶绿素ａ（Ｃｈｌ－ａ）相对较高,混养菲律宾蛤仔的围隔Ｃｈｌ－ａ较低;在投饵的基础上施肥后甲     

对虾池封闭式三元综合养殖的实验研究↑（*）

采用海水陆基围隔实验法探讨以对虾为主的中国对虾（ Ｐｅｎａｅｕｓ ｃｈｉｎｅｎｓｉｓ） 、罗非鱼（ Ｏ．ｍｏｓｓａｂｉｃｕｓ×Ｏ．ｎｉｌｏｔｉｃｕｓ） 和缢蛏（ Ｓｉｎｏｎｏｖａｃｕｌａ ｃｏｎｓｔｒｉｃｔａ） 投饵混养的最佳结构及Ｎ、Ｐ 的利用率等,并比较其养殖效果。结果表明,对虾的成活率、规格和净产量分别为７０ ．７４ ～８１ ．９５ ％ 、９ ．１６ ～１０ ．２１ ｇ／ｉｎｄ 和４８５ ．４ ～５６７ ．６ｋｇ／ｈｍ２ ;罗非鱼的出塘规格和净产量为２０２ ．４ ～２４２ ．５ ｇ／ｉｎｄ 和６６ ．９ ～１９１ ．９ ｋｇ／ｈｍ２ ;缢蛏的出塘规格和净产量分别为５ ．２３ ～６ ．１２ ｇ／ｉｎｄ 和１４０ ．４ ～４５６ ．５ ｋｇ／ｈｍ２ 。最佳结构与放养个体数的配比为对虾７ ．２１ ｉｎｄ／ｍ２（ 体长２ ｃｍ 左右） 、罗非鱼（ 体重１５０ ｇ 左右）０ ．０８ ｉｎｄ／ｍ ２ 和缢蛏（ 壳长３ ｃｍ 左右）１４ ｉｎｄ／ｍ２ 组,其Ｎ、Ｐ的总利用率为２３ ．３９ ％ 和１４ ．６６ ％ 。     

不同单养和混养海水实验围隔浮游生物的研究

1995年6～10月和1996年6～8月对中国对虾单养及其与台湾红非鲫、菲律宾蛤仔、海湾扇贝或缢蛏的不同混养实验围隔浮游生物的研究结果表明:养殖管理措施和放养种类对围隔浮游生物种类和生物量都会产生一定影响,其中前者往往具主要作用。投饵养殖时围隔浮游植物以20μm以下的种类为主,生物量较低,其中混养台湾红非鲫的围隔叶绿素a(Chl-a)相对较高,混养菲律宾蛤仔的围隔Chl-a较低;在投饵的基础上施肥后甲藻等鞭毛藻类易大量发生成为优势种,浮游植物生物量较单纯投饵时有所升高,但单养和混养对围隔Chl-a的影响不明显。非鲫捕食往往导致大型桡足类在浮游动物生物量中的比例下降,贝类则通过食物竞争同时使桡足类生物量降低和种类小型化,由于非鲫与海产贝类的食物灶存在一定分化,二者混养至少对贝类有利,因此鱼虾贝混养应较鱼虾混养或虾贝混养效果更好。     

中国对虾与海湾扇贝投饵混养的实验研究

用放在海水池塘中的8个陆基围隔(5.0m×5.0m×1.8m),研究中国对虾(Penaeuschinensis)与不同密度海湾扇贝(Argopectenirradians)投饵混养的放养方式、生产力和极限放养量.对虾体长(2.85±0.16)cm,扇贝壳长(1.10±0.12)cm,放养密度分别为6.0尾/m2和0,1.5,4.5,7.5粒/m2,用投饵和施肥(鸡粪和化肥)饲养.结果表明,扇贝密度为0和1.5粒/m2时,对虾的成活率无显著差异.混养(扇贝1.5粒/m2)时对虾的出塘体长、体重和产量分别比单养高2.5%,3.8%和6.5%;当扇贝密度高于1.5粒/m2时,对虾的平均体长、体重和产量随扇贝密度的增加而显著减少(P＜0.05).扇贝密度为1.5和7.5粒/m2时,其产量由470kg/hm2增至1236kg/hm2;当扇贝密度高时,去壳后湿重占体重的百分数从(42.84±3.44)%降至(37.88±4.26)%.扇贝的极限放养量为600～800kg/hm2,适宜放养密度为1.0～1.5粒/m2.     

虾池溶解有机碳动态分析

在实验室条件下,通过对虾养殖和混养海湾扇贝两组实验,对池水溶解有机碳及其动态特征作了初步分析,结果表明：溶解有机碳（ＤＯＣ）在对虾饲喂前期呈几何对数增长,其中混养池（ｅｘ－１）的增长曲线呈阶段性增长态势;单养池（ｅｘ－２）则表现为急速增长。有机物溶解速率呈指数衰减趋势,经回归拟合得速率方程为Ⅰ－ＲＡ１＝－ｌｎ（ＣＡｔ／ＣＡ０）＝０９９１７－００１００１７ｔ２;Ⅱ－ＲＡ２＝－ｌｎ（ＣＡｔ／ＣＡ０）＝１４１５－００１４２９ｔ２。     

烟台浅海区不同养殖系统养殖效果的比较

于１９９８年４月５日至６月２３日，在山东烟台市四十里湾海区进行了３种养殖模式养殖效果比较的模拟实验。在该海区岸边建立了栉孔扇贝（Ｃｈａｍｙｓ ｆａｒｒｅｒｉ）单养，栉孔扇贝和海带（Ｌａｍｉｎａｒｉａ ｊａｐｏｎｉｃａ）混养，栉孔扇贝、海带和刺参（Ａｐｏｓｔｉｃｈｏｐｕｓ ｊａｐｏｎｉｃｕｓ）混养等３个系列、９个养殖系统和１个对照系统（５．０ｍ＊２．０ｍ＊１．０ｍ，日换水量１００％），进行对比实验。     

Effects of Stocking Size and Density of Tilapia on Macrobrachium rosenbergii in Polyculture

Studies were conducted to determine the effect of stocking size and density of prawns in polyculture.
In one experiment, postlarval prawns (av. wt. 0.02 g) were stocked in six 0.02 ha earthen ponds at 35,00O/ha. Two ponds were stocked with tilapia fry (av. wt. 0.14 g) and two were stocked with tilapia fingerlings (av. wt. 30.1 g), each at 10,000/ha. Two control ponds had no tilapia. Tilipia stocking size had no effect on prawn growth. Mean weight of prawns after 70 days of culture ranged from a low of 4.5 g when cultured with tilapia fingerlings to a high of 6.6 when cultured in monoculture. Prawn survival was adversely affected by tilapia fry. Average prawn survival in tilapia fry ponds was 65% compared to 75% and 91%, respectively, in tilapia fingerling and monoculture ponds.
In a second experiment, postlarval prawns were stocked in nine 0.02 ha earthen ponds at 40,000/ ha. Six ponds were stocked with 30 g tilapia fingerlings, three at 5,000/ha and three at 15,000/ha. Three control ponds received prawns only. After 100 days of culture, prawn weight ranged from an average of 15.9 g in monoculture ponds to 11.5 g in polyculture ponds. Survival was highest (93.8%) in low density polyculture ponds. Survival was lowest (85.6%) in prawn monoculture ponds. Tilapia reproduction had a negative impact on shrimp production.     

有机海水围塘养殖生态系统能量收支与利用效率研究

对连云港市宋庄镇有机海水养殖基地的海水围塘南美白对虾—缢蛏—梭鱼混养系统和南美白对虾单养系统的能量收支与利用效率进行了研究。结果表明,在有机水产养殖方式下,混养系统中能量输入、输出分别为10.54和8.37MJ/m2,单养系统能量输出、输入分别为13.45和10.72MJ/m2。混养系统的光能利用率、光合能转换效率、生物能转换效率、总能转化率和底泥沉积率分别为0.18%、34.51%、48.11%、16.89%和62.41%,单养系统相对应的数据分别为0.19%、24.95%、24.04%、11.17%和68.54%。混养系统除光能利用率外,其他指标均优于单养系统,底泥沉积率亦小于单养系统。从综合生态经济指标来看,混养系统也优于单养系统,但2者综合生态经济指标(EY)均小于1,混养和单养系统都具有提高经济效益和生态效益的潜力。     

Comparison of Tilapia Monoculture and Carp Polyculture in Fertilized Earthen Ponds

A comparison of a monoculture of Nile tilapia Oreochromis niloticus and a polyculture of carps (silver carp Hypophthalmichthys molitrix; rohu Labeo rohita; and mrigal Cirrhinus mriga la; ratio 4:3:3) was carried out in 200-m² earthen ponds fertilized with cattle manure and supplemented with inorganic fertilizer at 3-kg nitrogen and 1.5-kg phosphorus/ha per day. A control treatment of a tilapia monoculture without fertilizer inputs was included to assess the effect of pond basal fertility. Net yields of 23.5 kg/pond per 112 d (3.8 t/ha per 1 yr) in the tilapia monoculture and 19.2 kg/pond per 112 d (3.1 t/ha per yr) in the carp polyculture were not significantly different; net yields from unfertilized tilapia monoculture ponds were negative. In the carp polyculture, silver carp was the dominant species at harvest contributing 73% of the total net fish production compared to 9% and 19% by rohu and mrigal, respectively. Water quality data suggested that tilapia yields could have been further improved by increasing fertilization rate but that critical dissolved oxygen concentration constrained this option for carp polyculture.     

Economic and Risk Analysis of Tilapia Production in Kenya

Commercial production of tilapia in Kenya has potential for expansion, but growth and development of the tilapia industry in Kenya will depend upon its profitability and the effect of associated risks. Data from pond experiments, on-farm trials, and farm surveys were used to develop enterprise budgets and a risk analysis for nine production scenarios. The nine scenarios include: 1) monoculture of sex-reversed male tilapia fed either rice bran, a pelleted experimental diet, or a pelleted pig finisher diet; 2) clarias monoculture fed with each of the three diets; and 3) tilapia-clarias (sex-reversed male fingerlings) polyculture fed with each of the three diets. Net returns/ha were highest for production with the pig finisher diet, with clarias in monoculture the highest followed by tilapia in monoculture and then the polyculture system. The lowest net returns/ha were obtained with clarias fed rice bran. Profitability was affected by feed cost and tilapia survival. Tilapia monoculture systems had lower probabilities of financial losses than either clarias monoculture or the polyculture system. Use of the pelleted diets also resulted in lower probabilities of financial losses. Lower yields from the rice bran feed scenario resulted in its greater sensitivity to fluctuating costs of rice bran and survival of tilapia.     

Evaluation of the production potential of Macrobrachium rosenbergii (de Man) in monoculture and in polyculture with Nile tilapia and common carp in Saudi Arabia

The feasibility of polyculture of Macrobrachium rosenbergii (de Man) with two fish species, Nile tilapia, Oreochromis niloticus (L.), and common carp, Cyprinus carpio L., was examined and compared with monoculture of M. rosenbergii in 100-m² ponds. Overall percentage of females (56.8%) was higher than that of males (43.2%). The proportions of females, males and their morphotypes did not differ significantly between monoculture and polyculture. After 196 days of culture, the mean harvest weight of prawns in monoculture (30.2 g) was significantly greater than that in polyculture (21.3 g). Yield in monoculture (1152 kg ha^-1) was significantly greater than (1.62 times) that of polyculture (711 kg ha^-1). Total yield from polyculture including yield of tilapia (2544 kg ha^-1) and common carp (2999 kg ha^-1) was almost five times as great as that of prawn monoculture. Survival and food conversion rate of M. rosenbergii did not differ significantly between monoculture and polyculture.     

不同密度的石莼与中国对虾的混养实验

在10个水族箱(53cm×24cm×23cm)中各放养中国对虾(Penaeuschinensis)4尾,混养孔石莼(UluaPertysavar)0、4g、6g、8g和10g,采用投饲精养.结果表明,孔石莼能有效吸收N、P营养盐,提高对虾对饲料中氮的利用率(42.7%～212.9%),水质状况也优于单养对虾.混养的综合养殖指数高于单养对虾.对虾密度为320-480g@m-3,石莼密度为400～600g@m-3时,可以进行免充气养殖.     

Tilapia–Shrimp Polyculture in Negros Island,Philippines: A Review

Tilapia–shrimp polyculture has played an important role in current efforts to control luminous bacterial disease caused by Vibrio harveyi. At present, green water technology is most extensively used by shrimp farmers in Negros Island in the central Philippines. While the contribution of tilapia as a biomanipulator is highlighted in the literature, the mechanism of action is not well understood. Data were gathered from shrimp ponds practicing two production systems: (a) green water system (probiotics + tilapia) and (b) closed/semiclosed system (probiotics alone). There was no difference between luminous Vibrio count (P < 0.05) in both systems, and water quality was found to be similar (P < 0.05). Because the green water system uses a bigger reservoir to raise the tilapia biomass, the net shrimp production was lower. In terms of direct cost of production, however, the green water system was 10–15% lower than the closed/semiclosed system because of significantly less aeration required. The polyculture maintained a more stable plankton environment during the early months of culture, which increased survival of shrimps. Various pathways are presented for the control of luminous bacterial growth in polyculture ponds: (a) fish feeding on organic wastes and conversion to feces; (b) selective fish foraging to increase the dominance of beneficial phytoplankton; (c) bioturbation of pond sediments; and (d) release in the water column of antimicrobials, fungi, or competing bacteria from the skin and gut mucus of tilapia.     

Polyculture of Freshwater Angelfish Pterophyllum scalare and Pacific white shrimp Litopenaeus vannamei in low‐salinity water

In this study, we evaluated the production potential of the polyculture of Freshwater Angelfish (Pterophyllum scalare, Cichlidae) and Pacific white shrimp (Litopenaeus vannamei). Two experimental trials were set up. The first trial entailed the use of a randomized design to investigate three treatments options: angelfish monoculture, shrimp monoculture, and fish and shrimp polyculture in 12 experimental 15 m² ponds. In the second trial, we investigated two treatments (polyculture of caged fish and uncaged fish) in 10 experimental units. In trial 1, polyculture negatively affected fish growth and survival. However, fish did not affect shrimp growth and the greatest profit was achieved in polyculture. In trial 2, caging fish improve the growth of both fish and shrimp. An economic analysis showed the greatest profit and benefit cost ratio for caged fish compared with uncaged fish. We conclude that growing P. scalare and L. vannamei together is a better strategy than shrimp monoculture in low‐salinity water. The use of caged fish in such a polyculture operation would enhance productivity and profitability.