复方三氯异氰尿酸对短沟对虾各期幼体的毒性

用静水试验法研究了复方三氯异氰尿酸（TCCA,强氯净）对短沟对虾（Penaeus semisuicatus）各期幼体的急性毒性。无节幼体和涵状幼体试验设6个质量浓度组（0．5mg·L-1、1．0mg·L-1、1．5mg·L-1、2．0mg·L-1、2．5mg·L-1、3．0mg·L-1）和1个空自组,糠虾幼体和仔虾设7个质量浓度组（1．0mg·L-1、1．5mg·L-1、2．0mg·L-1、2．5mg·L-1、3．0mg·L-1、3．5mg·L-1、4．0mg·L-1）和1个空白组,每组3个平行。结果显示,24h半致死质量浓度（LC50）和48h LC50的95％置信区间分别是无节幼体1．47～1．78mg·L-1和1．34～1．46mg·L-1;泾状幼体1．67～1．78mg·L-1和1．23～1．36mg·L-1;糠虾幼体2．05～2．25mg·L-1和1．58～1．79mg·L-1;仔虾3．14～3．38mg·L-1和2．59～2．78mg·L-1。安全质量浓度（SC）分别是无节幼体0．30mg·L-1,溢状幼体0．22mg·L-1,糠虾幼体0．34mg·L-1,仔虾0．55mg·L-1。试验结果可为短沟对虾育苗安全用药提供参考。     

提高斑节对虾人工育苗幼体成活率试验

1998年闽南地区斑节对虾人工育苗幼体成活率普遍很低。作者结合多年的斑节对虾育苗生产经验,采取综合的技术措施,进行提高幼体成活率的试验。从无节幼体到仔虾幼体后期(P_(10)—P_(16)),试验的总成活率为42.1％。     

不同盐度条件下氨氮对斑节对虾仔虾的毒性研究

开展了不同盐度条件下氨氮对斑节对虾仔虾毒性影响试验。结果表明,盐度为3.0%时,氨氮24,48,72和96 h半致死浓度(LC₅₀)分别为91.32,53.92,40.70和25.77 mg/L;盐度为2.5%时,分别为91.95,50.05,35.76和33.71 mg/L;盐度为2.0%的条件下,分别为164.46,98.56,71.05和44.13 mg/L;盐度为1.5%时,分别为97.19,63.97,31.83和26.04 mg/L;盐度为1.0%时,分别为74.79,21.89,13.55和10.81 mg/L;盐度为0.5%时,分别为58.17,12.98,10.46和6.01 mg/L;在盐度3.0%,2.5%,2.0%,1.5%,1.0%和0.5%时,氨氮的安全浓度(SC)分别为2.577,3.371,4.413,2.604,1.081和0.601 mg/L。指出,盐度对氨氮的毒性有较大的影响,盐度过高或者过低,都会增强氨氮对斑节对虾的毒性。提出,斑节对虾仔虾育苗应在盐度2.0%、氨氮对斑节对虾仔虾的毒性最小时进行生产。     

斑节对虾幼体链壶菌病的防治试验

在斑节对虾无节幼体池前２～３小时用０．０１５～０．０２０ｍｇ／Ｌ浓度的亚甲基蓝或三氟乐灵作预防,１～２天后发现有链壶菌感染时再用０．０２０ｍｇ／Ｌ浓度的亚甲基蓝或０．０２０～０．０３０ｍｇ／浓度的三氟乐灵治疗。两种药物比较,三氟乐录能有效防治链壶菌病,其有效浓度为０．０２０～０．０５０ｍｇ／Ｌ;而亚甲基蓝在链壶菌感染不严重时才有效,若感染严重或无节幼体下池前未施药预防,待发病后再用药,治疗无效。     

悬浮物对中国明对虾幼体急性毒性效应研究

本文通过室内模拟试验研究水体中悬浮物对中国明对虾不同幼体期生长的急性毒性效应。以无节幼体、溞状幼体、糠虾幼体和仔虾为试验生物,设置不同悬浮物质量浓度的试验组,并对死亡幼体进行计数,建立死亡率和悬浮物质量浓度对数的响应关系,求解中国明对虾幼体96h半致死质量浓度值。试验结果表明,悬浮物对中国明对虾4个时期幼体的生长均具有显著影响(P0.01),悬浮物质量浓度与幼体死亡率呈线性关系,死亡率随悬浮物质量浓度的增加而升高;无节幼体、溞状幼体、糠虾幼体、仔虾的96h半致死质量浓度分别为741.31、457.09、912.02mg/L和1023.29mg/L,线性相关系数分别为0.9771、0.9753、0.9859、0.9798。4种幼体中溞状幼体受悬浮物影响最大,仔虾受影响最小。     

亚硝酸盐氮对罗氏沼虾幼体的毒性试验

罗氏沼虾( Macrobrachium rosenbergii)幼体对亚硝酸盐氮的忍耐性随接触时间的增加而明显降低,本试验结果表明,亚硝酸盐氮对罗氏沼虾第9 期幼体的毒性:24 h 的半致死浓度为39.81 m g/L,48 h 的半致死浓度为25.63 m g/L,96 h 的半致死浓度为9.71 m g/L,安全浓度为0.97 m g/L。     

华师斑节对虾幼体饵料养虾试验报告

华师斑节对虾幼体饵料，为华南师范大学生物系温说洪副教授和海康县两水一牧办公室主任曹耐工程师共同研制的饵料。该饵料经多次反复养虾试验观察，从小水体到大水体，从与进口料配合饲养，到以华师料单养，华师料均优于目前各种进口的幼体饵料，现已成功地培育出1．0～1．2厘米虾苗547。88万尾。     

斑节对虾幼体发育的有效积温,生物学零度和耐温实验研究

在实验室条件下，通过记录４组温度下斑节对虾溲状幼体和糠虾幼体的发育时间，运用数理统计方法计算出溲状幼体和糠虾幼体各期的有效积温及其生物学零度。溲状幼体和糠虾幼体６个发育期中，Ｚ２耐高温的能力最弱，其余５个期无显著差异。在溲状幼体和糠虾幼体阶段，随着幼体的生长发育，耐低温（１０－１１℃）的能力逐渐提高。     

Efficacy of silicone-coated ascorbic acid and ascorbyl-2-polyphosphate to fast-growing tiger shrimp (Penaeus monodon)

Growth, survival, tissue ascorbate concentration and collagen content were studied in fast-growing Penaeus monodon fed two ascorbic acid (AA) derivatives. Prior to the experimental trial, shrimp (initial body weight: 0.9 ± 0.4 g) were fed on a diet lacking vitamin C for 5 weeks. During the following 13-week experiment, the shrimp (initial body weight: 8.2 ± 0.7 g) were given one of five squid-meal-based diets. The dietary treatments consisted of a diet lacking vitamin C, two diets supplemented with either 500 or 1000 mg AA kg⁻¹ in the form of silicone-coated AA, and two diets supplemented with either 500 or 1000 mg AA kg⁻¹ in the form of ascorbyl-2-polyphosphate. Shrimp gained 18.3 g in 13 weeks. The AA-free diet group exhibited the lowest growth rate, feed intake and survival (26.8%) after 4 weeks. Hepatopancreatic ascorbate and muscle collagen content were significantly ( P < 0.05) lower in AA-deprived shrimp. At the end of the feeding trial, growth rate and survival were not significantly ( P > 0.05) different among groups fed AA-supplemented diets. Hepatopancreatic and haemolymphatic ascorbate concentrations were significantly ( P < 0.05) higher in groups given ascorbyl-2-polyphosphate than in groups given silicone-coated AA. A supplement of 500 mg AA kg⁻¹ diet in the form of either silicone-coated AA or ascorbyl-2-polyphosphate was adequate for optimal growth. But ascorbate concentrations in tissues remained much below saturation levels with a supplement of 1000 mg AA kg⁻¹ diet. It is questionable whether the established vitamin C requirements for P. monodon are adequate to maintain tissue ascorbate in fast-growing juveniles.     

斑节对虾杆状病毒在感染对虾中肠腺中的分布

利用组织切片法研究了斑节对虾杆状病毒（MBV）在养殖早期班节对虾及养成期斑节对虾中肠腺各部位的分布特点。斑节对虾的中肠腺可分为头部、亚头部、中部、亚尾部和尾部等5个部分，其上皮细胞包括E细胞、F细胞、B细胞和R细胞等4种类型。头部和尾部均以E细胞为主、亚头部、中部和亚尾部均以R细胞为主。在感染度较轻的样本中，MBV一般只感染F细胞、R细胞和B细胞。感染度较重时，E细胞也同时受累。在养殖早期虾和养成期虾中，MBV相对感染度在中肠腺各部分的分布均以中部最高，而且以中部的中间最高，离中部越远，相对感染度越低。     

Maturation diet based on fatty acid content for male Penaeus monodon (Fabricius) broodstock

The contents of three essential fatty acids, arachidonic acid (AA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), from wild Penaeus monodon broodstock were evaluated in comparison with natural diet fed P. monodon. Spermatophores of wild male broodstock contained higher levels of AA than those of artificial diet fed males. Polychaetes had higher proportion of AA to EPA and DHA at 5.8:5.5:1 in mud polychaetes followed by 12:7:1 in sand polychaetes, while DHA was a preferential n‐3 highly unsaturated fatty acid (HUFA) in squids and fish. The experimental feed was constructed to simulate the HUFA profile of polychaetes (AA:EPA:DHA as 5:1:1) and then fed to farmed male black tiger prawn broodstock for 1 month. The results exhibited comparable reproductive characteristics to wild male suggesting the possibility of replacing wild males with pond‐reared males. Rearing farmed males in a test unit for a month did not reduce the quality of prawn sperm. Reproductive performance indices (sperm sac weight, total number of sperm, percentage of live sperm, percentage of abnormal sperm) from the males of all treatments were not statistically different except in males fed with pellets. Control (live feeds) and combined diet provided better reproductive performance in pond‐reared males. Analysis of AA, EPA and DHA in reproductive tissues, hepatopancreas and muscle of treated animals in each treatment revealed an accumulation of dietary HUFA into reproductive tissues. No evidence of transfer of HUFA from hepatopancreas or muscle to spermatophore was found.     

Penaeus monodon (Fabricius) and Penaeus merguiensis (de Man) biculture in East Java, Indonesia

Shrimp farmers in South-East Java have recently observed a decline in Penaeus monodon (Fabricius) production. To stabilize overall production, some farms have switched partially to biculture of P. monodon and P. merguiensis (de Man). The production from 33 ponds in two of these farms was analysed. In addition, the water quality in 10 ponds was monitored over the entire culture period. Information was also available on the post-larvae (PL) source and feed used per pond. Water quality remained stable during the culture period and there was no accumulation of organic material during the second half of the culture period. Stocking P. merguiensis 2 months after P. monodon partially compensated for the low production of P. monodon, thereby stabilizing overall production. When the production of P. monodon is low, the production of P. merguiensis is high and vice versa (P<0.001). Feed source had no effect on production when stocking density was included as a covariable in the analysis (P > 0.05), while P. monodon PL source caused production to differ by a factor of three (P<0.001). It was concluded that biculture of P. monodon and P. merguiensis is an effective way to stabilize overall shrimp production.     

Acute toxicity of nitrite to mud crab Scylla serrata (Forsskål) larvae

Early larval stages of mud crab Scylla serrata were exposed to different concentrations of nitrite (40, 80 and 160 mg L⁻¹ and a control, without added nitrite) and three salinity levels (25, 30 and 35 g L⁻¹) using a static renewal method. No interactive effect of nitrite and salinity was detected. Estimated LT₅₀ in 96‐h toxicity tests decreased in all stages with increasing nitrite concentrations in all salinity levels. The 96‐h LC₅₀ values of nitrite‐N were 41.58, 63.04, 25.54, 29.98 and 69.93 mg L⁻¹ for zoea 1, 2, 3, 4 and 5 respectively. As the larvae grew, they showed a progressive increase in tolerance to nitrite. The toxicity of nitrite to larvae increased with exposure time. The median lethal concentration was not affected by salinity. The chloride component of salinity within 25–35 g L⁻¹ did not seem to be as effective in alleviating toxicity as has been reported in other crustacean species. Based on 96‐h LC₅₀ and an application factor of 0.1, the ‘safe level’ of rearing mud crab larvae was calculated to be 4.16, 6.30, 2.55, 2.99 and 6.99 mg L⁻¹ nitrite‐N for zoea 1, 2, 3, 4 and 5 respectively.     

Effects of crushed conspecifics on growth and survival of Penaeus monodon Fabricius post larvae

In the present study, the hypothesis tested was that Penaeus monodon post‐larvae (PL) experience lower growth when exposed to crushed conspecifics, which was achieved by exposing individual P. monodon PL with abundant food for 4 weeks to a gradient from 0 to 100 crushed conspecific PL L^?1. Both dry weight (48.5±7.2 mg) and body size (28.0±1.3 mm) of animals exposed to 1 macerated PL L^?1 were significantly (P≤0.011) higher than those of animals in treatments with 0, 5 and 10 crushed PL L^?1 (average over treatments: 25.6±3.2 mg; 23.4±0.5 mm). All animals died within 1 week when exposed to 70 and 100 crushed PL L^?1, and within 3–4 weeks when exposed to 50 and 30 crushed PL L^?1. Exposure time affected mortality and it appeared that LC₅₀ values decreased from 60 to 13 crushed PL L^?1 from 1 to 4 weeks' exposure. Survival of P. monodon PL was negatively correlated to pH, biological oxygen demand, ammonia and nitrate. In conclusion, low dose of crushed conspecifics has a stimulatory effect on P. monodon PL, as larvae were heavier and larger, while high doses cause high mortality.