山东沿海腹洞式毛虾单桩张网试验报告

单桩张网在渤海捕捞毛虾时，损害大量经济鱼虾的幼体，严重地破坏了渔业资源。为保护经济鱼虾的幼体，合理利用毛虾资源，作者根据毛虾和其他经济鱼虾幼体的不同习性和游泳能力，设计了腹洞式毛虾单桩张网。该网的主要特点是，在张网腹部开有一个较大的三角洞，经济鱼虾的幼体受惊后可由此下潜逃逸，或在流速较小时由此外返逃逸。两年来的生产对比试验表明，效果显著。腹洞式毛虾单桩张网比现有生产网的平均网次产量增加20．64％。其中，毛虾增产38．14％，释放经济鱼虾的幼体58．94％。     

日本对虾越冬亲虾性腺促熟及工厂化育苗技术研究

1997、1998年利用越冬亲虾进行性腺促熟,用镊烫法切除眼柄,促进亲虾发育。结果:两年共培育亲虾雌虾8204尾。雄虾5683尾,获交尾虾5360尾。交尾率为71.81％。每年两批育苗,共利用水体1720m~3,育出0.7～1.1cm的虾苗12450万尾,平均单位水体出苗量为7.24万尾/m~3,效益显著。     

鲈与中国对虾混养试验

１９９５、１９９６年进行鲈与中国对虾混养试验，利用鲈摄食病虾及小型糠虾类，阻断病毒传播，推迟了对虾发病，试验池产量，效益成活率均高于对照池。     

Pathogenicity of halophilic Vibrio harveyi in giant freshwater prawns (Macrobrachium rosenbergii De Man)

In this study, the phenotypic and pathogenic properties in freshwater host were characterized in 14 strains of halophilic Vibrio harveyi isolated from infected marine black tiger shrimp, Penaeus monodon. The lysogenic phenotype was assayed via prophage excision and mitomycin C induction. The bacteria were grouped into two types, corresponding to lysogenic and non‐lysogenic strains. The pathogenicity was determined via direct injection of bacterial cultures into post‐larval juvenile giant freshwater prawns, Macrobrachium rosenbergii De Man. All of the infected prawns showed similar symptoms and inflamed hepatopancreas. The V. harveyi isolates derived from the first‐injected infected prawns were re‐isolated and re‐injected into healthy giant freshwater prawns, in which they retained similar infectivity. Both lysogenic and non‐lysogenic Vibrio spp. showed identical virulence associated with 100% mortality within one day post‐injection. TEM micrographs showed hepatopancreatic nuclear deformation and lipid breakdown caused by lysogenic γ‐hemolytic VL19 and non‐lysogenic β‐hemolytic V33. However, the V33 strain was associated with severely disrupted mitochondria. None of the V. harveyi strains was able to produce a biofilm. Together, our findings indicate that the lysogenic and non‐lysogenic halophilic V. harveyi isolated from marine shrimps may use different virulence factors that are responsible for their pathogenicity in freshwater prawns.     

不同养殖模式的凡纳滨对虾品质的比较

仪器分析法(营养成份分析和质构分析)与感官评价法有机结合,以对虾口感为主要考核指标,建立对虾品质鉴定体系,并以此法对无公害海水养殖、传统海水养殖及传统淡水养殖对虾3种不同养殖模式下生产的对虾品质进行比较.结果表明:3种对虾的机体营养成分组成差异不大,只有无公害虾肌苷酸含量明显高于其余两组,达2.76 mg·g-1.氨基酸分析中表明:无公害海水养殖对虾的必需氨基酸、非必需氨基酸、鲜味氨基酸及氨基酸总量等指标优于其余样品;无公害虾的感官指标基本上与海水虾相似,3种虾的色泽和气味指标差异不明显(P＞0.05),无公害虾的滋味及口感均比其它两组对照好;多汁性指标则以淡水虾最佳.在质构分析方面,3种虾硬度指标差异显著(P＜0.05),无公害虾与海水虾在肌肉的弹性及咀嚼性无显著性差异(P＞0.05),与淡水虾差异显著(P＜0.05),其结果与感官评价基本一致.本文全面比较3种对虾品质上差异,揭示对虾口感差异内在因素,为对虾品质评价提供了方法和手段.     

Correction of black tiger prawn (Penaeus monodon fabricius) coloration by astaxanthin

After two months of feeding a group of juvenile black tiger prawn (Penaeus monodon) with a commercial feed (CF), their external pigmentation changed from its normal greenish-brown to a light blue. This condition was thought to be induced by a carotenoid deficiency in the feed. Nutritional improvement and hence correction of this condition was attempted by adding 50 ppm astaxanthin (Roche Ltd^®) into one feed (AF) and 5% addition of brown algae (Chnoospora minima) into a second feed (BF). After four weeks of feeding, the prawns fed on AF reverted to their normal greenish-brown pigmentation. The carotenoids present in the BF feed increased carotenoid content in the prawns, but the levels were not high enough to correct the blue coloration. Analysis of carotenoid content in the shells of the groups showed 318%, 57% and 14% increase for AF, BF, and CF respectively, with 70–90% of the total carotenoid being in the form of astaxanthin. Deposition of astaxanthin was higher in the shell than in the flesh, with deposition in the flesh plateauing after two weeks, whilst deposition in the shell increased steadily.

The importance of these findings to the marketing of cultured shrimps is discussed.     

A test of two methods for marking larvae and postlarvae of the giant freshwater prawn, Macrobrachium rosenbergii

This paper describes the successful use of two tagging systems, both produced by Northwest Marine Technology Inc., on larval and postlarval giant freshwater prawns, Macrobrachium rosenbergii. Visible implant (VI) elastomer tags (a coloured liquid that solidifies under the epidermis) were used on stage XI larval prawns (mean weight 0.01 g) and postlarval prawns (mean weight 0.07 g). VI alphanumeric tags (small biocompatible plastic labels also inserted under the epidermis) were tested on postlarval prawns (from a weight of 0.5 g). Tags were inserted using clove oil as anaesthetic, and survival, mortality and growth rates of tagged animals were compared with those of controls that were handled but not anaesthetized or marked. Twenty per cent of the larval prawns (the smallest of the group) died just after tagging, but thereafter the remaining prawns survived well, as did all the tagged postlarval prawns. Visibility of the VI elastomer tags in larval prawns deteriorated with time, though 79% of marks were still visible to the naked eye 70 days after tagging. VI elastomer tags in the postlarval group remained clearly visible for up to 100 days. Visibility of the VI alphanumeric tags fell shortly after tagging, but remained adequate thereafter. Moult rates in control and tagged animals were the same in larvae with VI elastomer tags and postlarvae with VI alphanumeric tags, but the moult rate in the postlarval prawns given elastomer tags was slower than in controls. Rates of growth were similar in tagged (elastomer and alphanumeric) and control postlarval prawns, once the size‐dependent mortality of tagged larval prawns was taken into account. We conclude that VI elastomer tags could be used to mark small numbers of individual larval and immediately postlarval prawns for periods of several months, and that VI alphanumeric tags could be used to mark an unlimited number of individuals from a size of approximately 0.5 g.     

The effect of selected seed oils on the fatty acid composition and growth of Penaeus indicus

Various seed oils included in artificial diets for Penaeus indicus were examined for their influence on weight gain and tissue lipid composition. Four seed oils were selected on the basis of known differences in their fatty acid compositions, principally those essential fatty acids of the linolenic (ω3), linoleic (ω6) and oleic (ω9) type series. A 35-day feeding trial showed no significant growth differences between prawns fed either sunflower, linseed, soybean or groundnut oil at a 5% level of inclusion. Proximate carcass analyses on the experimental animals indicated an increase in depot lipid in comparison to equivalent wild caught prawn.The component fatty acids of total lipid extracts from the fed prawns showed a significant degree of correlation with those of the dietary lipid intake. In particular, high tissue depot levels of linoleic acid (18: 2ω6) were associated with all seed oil diets. This may be compared with similar analyses on wild caught prawns in which a higher degree of lipid unsaturation was attained by proportionate increase in the longer chain homologues (>C₂₀ chain length) of the ω3 and ω6-type fatty acids. Under present dietary regimes, therefore, there appears to be limited capacity for biosynthetic interconversion of essential fatty acids to longer chain polyunsaturates of the same typed series. Related experience in fish nutrition suggests that precise dietary levels and a balanced ratio of $\text{ω3}\text{ω6}\text{-}\text{type}$ fatty acid may be necessary for efficient lipid metabolism.     

海水桡足类的营养及在鱼、虾、蟹幼体培育中的应用

海水桡足类在海洋食物网和生态系统中具有重要的地位,是各种海洋经济鱼类和甲壳类的重要饵料,也是经济水产动物人工育苗阶段的优质活饵料源。研究海水桡足类营养和应用效果,对提高海水鱼、虾、蟹类幼体变态率、成活率、苗种质量和育苗成功率具有重要的意义。     

Prey ingestion and live food selectivity of marble goby (Oxyeleotris marmorata) using rice field prawn (Macrobrachium lanchesteri) as prey

Marble goby (Oxyeleotris marmorata), a carnivorous fish native to freshwater in Asia-Pacific region, is a high-valued species in many Asian countries. The present study consisting of three experiments was conducted to determine the appropriate density, size and ingestion time of marble goby fingerlings on rice field prawn (Macrobrachium lanchesteri) as prey. Results showed that the ingestion rate of marble goby fingerlings (0.26-1.43 g size) on prawns (9-12 mm in length) had an asymptotic pattern peaked at a predator to prey ratio of 1:20. Marble goby fingerlings did catch prawns during both daytime (07:00-17:00 h) and nighttime (17:00-07:00 h), but the ingestion peaked during nighttime period. The hourly ingestion rate during nighttime was significantly higher than that during daytime for the smaller-size marble goby fingerlings of 0.26-0.87 g, while there was no significant difference in the hourly ingestion between nighttime and daytime for the larger-size marble goby fingerlings of 1.43 g. The daily ingestion of marble goby fingerlings on prawns (mg consumed prawns/goby/day) increased significantly with increasing average weights (g) of marble goby fingerlings (Y = 27.6 + 47.8X, n = 30, r² = 0.86, p < 0.05). Results also showed that the preferred prawn size of marble goby fingerlings of average weights of 0.26-4.18 g was small (9-12 mm) with positive electivity index of 0.19-0.33, and the shift from small- to medium-size (12-14 mm) prawns was slow. The present study has demonstrated the feasibility of using rice field prawns as live foods to nurse marble goby fingerlings.     

A review on the diseases of freshwater prawns with special focus on white tail disease of Macrobrachium rosenbergii

Freshwater prawns, particularly, the Giant Freshwater prawn Macrobrachium rosenbergii, are one of the most economically important farmed species in the world. Faced with increasing disease problems in penaeid shrimp culture, farmers turned to freshwater prawn farming. Freshwater prawns were considered relatively less susceptible to diseases. However, with intensification of culture and increased world trade of the farmed species, emerging diseases are beginning to constitute an increasingly serious health problem in freshwater prawn culture. This article is a review of the important diseases reported in freshwater prawns, with particular emphasis on the white tail disease of M. rosenbergii as it is the most important disease recorded to date and also the most well studied among the diseases of freshwater prawns. Steps to be taken for proper health management in the farming of this species is also touched upon.     

“太湖1号”杂交青虾规模化繁育技术研究

利用53hm2标准化鱼池,采用雌雄亲虾同池的放养模式与集中投放抱卵虾孵化培育模式2种模式进行“太湖1号”杂交青虾的规模化繁殖试验。结果显示,本期共繁殖生产虾苗33533．86万尾,31878．33kg。雌雄亲虾同池培育的产苗量比集中投放抱卵青虾培育的产苗量要低36．49～69．26kg／hm2,或132．85万。143．607万尾／hm2,苗种规格大小差异大。雌雄亲虾同池培育的捕苗时间从7月18日到8月25日,共计38d,集中投放抱卵亲虾培育池的苗规格较一致,捕苗时间为期25d,捕捞时间缩短了13d。这表明,集中投放抱卵虾孵化培育模式可作为青虾规模化繁殖生产的优选方式。     

Modified Atmosphere Packaging (MAP) for Control of Black Spot Formation in Chilled Prawns

The marketing of organically labeled prawns is predominately in a cooked or raw frozen form to avoid the development of melanosis (black spot). Certification for organic status prohibits the use of any added chemicals. The application of 60% CO₂/40%N₂ modified atmosphere to chilled (raw) prawns using two species of prawn was investigated for the ability to control black spot formation. Sensory assessment and microbiological counts were used to determine the end of product shelf life. Modified atmosphere packaged (MAP) prawns exhibited no melanosis for up to 16 days. The high quality life was retained for 12 days; shelf life of 16 days, according to standard microbiological criteria, was achieved, which is more than twice previously reported for non-MAP prawns. Results suggest MAP may be an effective method for the marketing of organically grown prawns as well as those produced by conventional prawn aquaculture without application of the normal chemicals used to prevent black spot.     

Effects of stocking density on the nutrient budget and growth of the western king prawn (Penaeus latisulcatus Kishinouye) in a recirculating aquaculture system

Intensification in the commercial culture of prawns can have a significant impact on the water quality and hence on the survival, growth and the surrounding environment. The present study aims to evaluate the effects of stocking density on the water quality and performance of the western king prawns (Penaeus latisulcatus) and the nutrient budget of the culture environment. Four stocking densities of 4, 8, 16 and 32 prawns m^?2 were tested in 12 recirculating systems. Prawn weight and specific growth rate increased with decreasing stocking density, while the survival rate showed the reverse trend. The mean total ammonia nitrogen, nitrate nitrogen, total phosphorus and soluble reactive phosphorus were significantly higher (P<0.05) at the higher stocking density. The nutrient budget revealed that the prawns could assimilate only 9.34–20.13% nitrogen and 4.97–11.25% phosphorus of the total nutrient inputs. The drained water at harvest was the major sink of phosphorus and nitrogen at stocking densities of 4, 8 and 16, which accounted for 45.59–64.82% and 44.28–65.62% of the total inputs, respectively, while a significant proportion of nitrogen sunk into the sediment at 32 prawns m^?2. The study suggested that the stocking densities of western king prawns can be up to 16 prawns m^?2 in the recirculating water environment.     

Production Characteristics of All‐male and Mixed‐sex Giant River Prawns,Macrobrachium rosenbergii,Grown in Earthen Ponds in Kentucky and Mississippi USA

Production and population characteristics of monosex male (all‐male) giant river prawns, Macrobrachium rosenbergii, were compared with a normal (mixed‐sex) population in separate studies in Mississippi and Kentucky (USA) under low and high density stocking conditions, respectively. In Study 1 (Mississippi), juvenile prawns were stocked into eight 0.05–0.06 ha ponds at 24,700/ha. The mean stocking weight of all‐male was 0.34 g and mixed‐sex was 0.39 g. Prawns were fed 23% crude protein “range cubes” and harvested after 120 d for the all‐male prawns and 112 d for mixed‐sex prawns. In Study 2 (Kentucky), juvenile prawns from each group were stocked into six 0.04 ha ponds at 60,000 juveniles per hectare. The mean stocking weight for all‐male was 0.38 g and for mixed‐sex juveniles was 0.34 g. Prawns were fed a commercial sinking pellet (33% protein) once daily at a standardized rate and harvested after 105 d. In both locations survival of mixed‐sex prawns and all‐male prawns was not significantly different and the final average weight of all‐male prawns was significantly greater than the average weight of mixed‐sex prawns. For the study in Kentucky, total production was not significantly different between treatments, whereas in Mississippi total production in the all‐male ponds was significantly higher than in the mixed‐sex ponds. For both studies, the production size index of all‐male prawns was significantly greater than that of mixed‐sex prawns. In terms of population structure, in all‐male ponds there was a significant increase in orange claw (OC) males compared with the mixed‐sex ponds both as a percent of sex and a percent of total population. The increase in OC numbers in all‐male populations may be due to a lack of females to stimulate the transition of males to the final, sexually mature, blue claw stage. As target weights increase from 20, 30, and 40 g, the all‐male populations were increasingly superior in terms of production (kg/ha) of those target sizes. The economic benefit of all‐male over mixed‐sex populations will be principally based on an examination of tradeoffs that primarily consider the cost difference of juveniles relative to the price differences for different final harvest weights.     

Effects of Stocking Density and Monosex Culture of Freshwater Prawn Macrobrachium rosenbergii on Growth and Production in Concrete Tanks in Saudi Arabia

Abstract This study was conducted to evaluate the effects of stocking density and monosex culture on growth, survival, yield and feed conversion ratio of freshwater prawn Macrobrachium rosenbergii in concrete tanks. Juvenile prawns with an average weight of 1.8 g were stocked into triplicate tanks at densities of 5, 10, 15 and 20 prawns/m², grown for 168 d and fed a 34% tilapia diet. Stocking density had significant effect on prawns. Final mean body weight decreased with the increasing density, being highest at 5 prawns/m² (29.6 9). and lowest at 20 prawns/m² (17.4 g). Total yield increased from 135 g/m² (1,350 kg/ha) at a density of 5 prawns/m² to 261 g/m² (2,610 kg/ha) at density 15/m^z to 245 g/m² (2,450 kg/ha) at 20/m^z. Feed conversion ratios were high and ranged from 3.7 (5 prawns/m²) to 5.6 (20 prawns/m²).
In monosex culture of freshwater prawns stocked in triplicate tanks at a density of 5 prawns/m² for 112 d, the all-male population had the best growth performance and feed conversion ratio, followed by the mixed-sex and all-female populations. The all-male population had 99% marketable prawns (>20 g) with an average yield of 159 g/m² (1,590 kg/ha); the mixed-sex population had 90% marketable prawns and the yield was 135 g/m^z (1,350 kg/ha); and the all-female population had 75% marketable prawns with an average yield of 108 g/m² (1,080 kgha).     

电驱虾捕捞技术的初步研究

海虾有陷于沙中，昼伏夜出的习性。因此一般拖网捕虾的产量，夜间比白天高。为了提高白天拖网捕虾的生产效果，本文报道了利用电刺激虾体来配合拖网捕虾的试验成果。试验通过对七百多尾墨吉对虾，用不同参数电刺激，探讨了虾在电刺激状况下的生理反应，得出了驱赶墨吉对虾的最佳电参数；讨论了设备和电极在海水中形成的电场强度分布情况。最后，简略介绍了试捕实践情况。     

POLYCULTURE OF THE FRESHWATER PRAWN (Macrobrachium rosenbergii) WITH TWO COMBINATIONS OF CARPS IN MANURED PONDS

A study was conducted to 1) evaluate the compatibility of prawns (Macrobrachiurn rosenbergii) with carps, especially the effect of the common carp (Cyprinus carpio); and 2) measure the ability of prawns to utilize the foods available in manured systems. Carps used were the silver (Hypophthalmichthys molitrix), bighead (Aristichthys nobilis), grass (Ctenopharyngodon idella) and common carp (Cyprinus carpio). Four ponds (0.09 to 0.17 ha) were stocked with silver, bighead and grass carps while common carp were stocked in only two ponds. Total fish densities were 8,600/ha where four carps were stocked, but only 6,200/ha when common carp were omitted. Post-larval prawns (wt 0.116 g) were stocked at densities of 17/m². Swine (approximately 60/ha of pond surface area) were housed on pond dikes so that fresh manure continuously entered each pond. Two lots of swine were fattened during the experimental period and loadings of swine manure were calculated based on hog size and feed consumption. Growth periods were 163 days for fish and 107 and 121 days for separate stockings of prawns. Gains in biomass by prawns averaged 714 kg/ha in ponds without common carp and 364 kg/ha in ponds containing common carp. Gains in biomass for both fish and prawns were 3,619 kg/ha (19.8 kg/ha/day) in ponds with common carp and 2,924 kg/ha (18.0 kg/ha/day) in those without common carp. Prawn survival was higher (X = 84.5% vs X = 72.5%), but final average weight of prawns was lower (2.64 vs 5.86 g) in the presence of common carp due to competition for food between common carp and prawns. Competition from carp is believed to have exerted less influence on prawn survival than predation on small prawns by larger, faster-growing prawns.     

Evidence of rapid transfer and bioaccumulation of Microcystin‐LR poses potential risk to freshwater prawn Macrobrachium rosenbergii (de Man)

Microcystins accumulate in aquatic organisms and can be transferred to higher trophic levels, eventually affecting vector animals and consumers. We examined three levels of an aquatic food chain (Microcystis aeruginosa, Daphnia magna and Macrobrachium rosenbergii) to identify the transfer efficiency and risk of microcystin on prawns. Samples were analysed using ultra performance liquid chromatography‐mass spectrometry (MS)/MS and microcystin‐LR (MC‐LR) distributions in prawn tissues were studied. The results showed that prawns accumulate MC‐LR both directly from M. aeruginosa and indirectly through D. magna which was pre‐exposed to M. aeruginosa. MC‐LR was detected in the gills, digestive tracts and hepatopancreas of the prawns 2 h after exposure. MC‐LR accumulated in prawns to 0.49 ± 0.04 μg g^?1 dry weight in hepatopancreas within 24 h, while it was not detected in muscle samples, and rarely appeared in blood samples in such a short period. Although MC‐LR was not detected in muscle, the head including hepatopancreas of the prawns accumulated troublesome amounts of MC‐LR. These results demonstrate that microcystis blooms in prawn farming potentially pose a risk to human consumers, although prawns may be exposed to the bloom for a very short time, hence regular monitoring of blue green algae population is recommended.     

渤海对虾死亡的研究

我们用各种方法估算了秋汛渤海对虾(Penaeus orientalis Kishinouye)的死亡值。总死亡系数的估算结果:用渔获尾数为相对资源量估计的10年平均旬死亡值,雌虾约0.25,雄虾约0.34;用y/f为相对资源量估计的12年旬平均死亡值,雌虾0.23,雄虾0.34;用世代分析(Pope 方法)估计的3年雌虾旬平均死亡值约0.30。交尾后部份雄虾死亡,我们找到了一个用性比资料估算雄虾交尾死亡的方法。估算结果,到10月末,雄虾交尾死亡系数约为0.65,并有陆续死亡现象,到12月初的累计死亡系数约1.05左右。我们在讨论了渤海秋汛对虾渔业的 F和f之间的关系后,认为当 f<1000,捕捞死亡随捕捞努力量的变化而变化;当f>1000,捕捞努力量的变化对捕捞死亡已无多大影响,所以渤海秋汛对虾渔业平均每 10天的捕捞死亡系数不能大于0.3。