Effects of Pond Renovation on White River Crayfish,Procambarus acutus acutus Production

Abstract

The effects of renovation on the production of white river crayfish, Procambarus acutus acutus were evaluated in ten 0.1-ha earthen ponds. The bottoms and levees of five ponds were reshaped with heavy equipment prior to planting sorghum-Sudan grass forage during the de-watered phase of the culture cycle. Five non-renovated ponds served as a control. The mean total length (TL) of the crayfish harvested from renovated ponds was significantly larger than those crayfish harvested from non-renovated ponds. The renovated pond harvest contained an estimated 43.2% carryover crayfish (>95 mm TL) in comparison to 7.6% in the harvest from non-renovated ponds. By weight, carryover crayfish constituted an estimated 69.3% of the harvest from renovated ponds, compared to 21.0% from non-renovated ponds. No difference was observed in the harvest between treatments; however, the low proportion of young-of-the-year crayfish in the renovated pond harvest may adversely impact future production.     

Estimation of the Dietary Lipid Requirement Level of the White Crayfish Procambarus acutus acutus

Six isonitrogenous and isoenergetic diets containing graded levels of lipid (menhaden fish oil) were fed to juvenile white crayfish ( Procambarus acutus acutus ) over a 10 week period. A significant depression in weight gain was observed in crayfish fed diets containing 9% or more lipid. There were no significant differences in growth of crayfish fed diets containing 0 to 6% lipid. Whole-body percentages of lipid and dry matter decreased, and protein increased in crayfish fed high-lipid diets. Dietary lipid did not appear to influence survival or molting frequency. Whole-body lipids generally reflected dietary fatty acid composition.     

Effects of Temperature on Feeding Activity of the White River Crayfish Procambarus acutus acutus1

Feed consumption by white river crayfish Procambarus acutus acutus in a 56-d laboratory study increased at a linear rate with water temperature over a range of 5 to 25 C. Feed consumption changed as water temperatures were cycled from 20–8–20 C (0.5 C/d) over a 68-d period and was the highest at the initial 20 C level and the lowest at 8 C. As water temperature increased, feed consumption rate increased; however, consumption never reached the initial rate at 20 C. Crayfish fed 3% and 6% of body weight were significantly larger than animals fed at 1% of body weight after 8 wk. Feed conversion ratios increased significantly with feeding rate. Based on this laboratory study, white river crayfish feed most effectively when water temperature is ≥ 15 C and the feeding rate is 3% of body weight/d.     

Effects of Harvest Period on the Production of White River Crayfish,Procambarus acutus acutus

Abstract

Crayfish harvest was initiated at a cool water temperature (15°C) and warm water temperature (20°C) from culture ponds (0.1 ha) with a resident population of white river crayfish, Procambarus acutus acutus.Crayfish were harvested for 24 days for a total of 1,977 trap-days/ha (March 9-May 12, 2000 from the cool-harvest treatment and May 5-June 15, 2000 from the warm-harvest treatment). The mean total length (TL) and production of harvested white river crayfish (WRC) was similar between treatments. The population structures of WRC from the cool and warm periods of harvest were substantially different; large WRC (≤100 mm TL) from the cool-harvest period were 3.1 times more abundant than large WRC during the warm-harvest period. A similar number of small WRC were harvested from the two treatments; however, those small WRC harvested during the warm period was significantly longer than the small WRC during the cool-harvest period. The estimated large WRC biomass contribution to the total harvest from the cool-harvest period was 37% in comparison to 15% during the warm-harvest period. The estimated dollar value of the production during the cool-harvest period was 40% more than that from the warm-harvest period.     

Acute Toxicity of 5% Non-Synergized Emulsifiable Rotenone to White River Crayfish Procambarus acutus acutus and White Perch Morone americana

Annual drawdown of crayfish culture ponds to plant forage crops also serves to eradicate most predaceous finfish. Without annual drawdown predaceous fish populations may reach numbers that can significantly reduce the crayfish crop. Frequent drawdown may not be feasible or desirable in some management schemes. Evidence in the literature suggests that differential toxicity of rotenone would allow removal of fish without harming crayfish in the same pond. In the current study, laboratory and in situ acute toxicity bioassays (96 h) were conducted with 5% non-synergized emulsifiable rotenone to define the maximum non-lethal concentration (LC₁₀₀) for white river crayfish Procambarus acutus acutus and the minimum lethal concentration (LC₁₀₀) for white perch Morone americana . Six concentration levels of rotenone formulation were tested in each of six toxicity trials with crayfish using dechlorinated tap water at 21–25 C. LC₀ (compensated for control mortality) was determined to be 3.0 mg/L. Significant crayfish mortality began at 4.0 mg/L. Acute toxicity to white perch was anticipated to be within recommended concentration levels on product label for similar fish, and was corroborated by laboratory bioassay (LC₁₀₀ of 0.15 mg/L). Both species were then tested together in laboratory aquaria utilizing pond water at room temperature. Concentration levels of 0.05–2.5 mg/L killed all white perch with no crayfish mortality. In the final phase of the study a 1.0 mg/L concentration of rotenone was applied to a pond containing both species held in cages. All white perch were dead within 24 h; no crayfish mortality was observed for the 96-h duration of the trial. It may therefore be possible to use this rotenone formulation to control white perch and other finfish in active crayfish culture ponds.     

Growth and survival of Procambarus acutus acutus (Girard, 1852) and P. clarkii (Girard, 1852) in competitive settings

Third‐instar young‐of‐the‐year (YOY) and juvenile Procambarus acutus acutus and P. clarkii stocked in aquaria, rice forage microcosms and a culture pond were evaluated in intraspecific‐ and interspecific‐competitive settings. Procambarus acutus acutus YOY, which were larger than P. clarkii YOY at stocking, grew and survived at significantly greater rates over fall‐, winter‐ and spring‐temperature courses in aquaria. Juvenile P. a. acutus starting an aquarium experiment with a mean total length (TL) size advantage survived at a significantly greater rate than P. clarkii juveniles. Growth rate of similar‐sized stocked P. a. acutus juvenile was significantly faster than that of P. clarkii juveniles in the same microcosms. Survival of juvenile P. clarkii in the microcosms with P. a. acutus was significantly less than when stocked alone. Estimated survival of 2200 P. a. acutus and 2200 P. clarkii YOY in a culture pond over a 174‐day grow‐out period was 84% and 57% respectively. Growth rate of these YOY P. a. acutus and P. clarkii was 0.48 and 0.40 mm TL day^?1. The body‐size advantage at hatching and through the faster growth of P. a. acutus was important in defining competitive interaction with P. clarkii.     

The Effect of Temperature on Feed Consumption and Nutrient Absorption in Procambarus clarkii and Procambarus zonangulus

Feeding characteristics of acclimated red swamp crayfish Procambarus clarkii and white river crayfish Procambarus zonangulus were determined at 8, 14, 20, 26, and 32 C. Food consumption rates of crayfish were directly related to temperature. Feeding was minimal at 8 C. At 14 CP. zonangulus consumed significantly more feed (5.5% body weight (BW/d) than P. clarkii (1.8% BW/d). At 32 C P. clarkii consumed significantly more feed (23% BW/d) than P. zonangulus (10% BW /d), reflecting species-specific thermal optimums for feeding. Differences in food consumption rates correspond to differences in the geographical distributions of these two species. Dry matter absorption rates ranged from 55% to 75% for both species without significant temperature effect. Patterns of protein and carbohydrate absorption were similar in P. clarkii and P. zonangulus. Protein absorption efficiency decreased from 45% to 10% as temperature increased from 8 C to 32 C. The total amount of protein absorbed increased seven- to ten-fold as temperature increased. Soluble carbohydrate absorption efficiency was reduced at low temperatures. However, absorption efficiency increased approximately five-fold as temperature increased from 14 C to 20 C, but did not change substantially as temperature was increased to 32 C. The total amount of carbohydrate absorbed increased approximately 15- to 26-fold as temperature increased. The protein to carbohydrate utilization ratio was similar between species, but varied dramatically with temperature. Both species absorbed between 2.5 and four-times more protein than carbohydrate at low temperatures (8 C and 14 C). At 32 C both species utilized approximately three times more carbohydrate than protein. In spite of reduced consumption at lower temperatures, crayfish absorbed a greater protein portion. At these low temperatures it appears that crayfish maximize the efficiency of protein absorption, presumably for maintenance and growth requirements. At high temperatures it appears that crayfish maximize energy intake, presumably to sustain higher metabolic rates due to increased activity levels. These apparent temperature-dependent nutrient requirements may influence natural foraging strategies or, for species in aquaculture, the effectiveness of commercial feed preparations. At high temperatures P. clarkii was more effective in consuming nutrients than P. zonangulus and may be more successful than P. zonangulus at these temperatures.     

克氏原螯虾养殖技术初探

改造低洼田 1 33hm2 养殖克氏原螯虾 ,合理种植水草 ,严把虾种放养关 ,加强水质管理 ,采取轮捕轮放技术 ,生产克氏原螯虾 5 10 4kg ,产值和利润均很显著。为农业增效、农民增收探索出一条发展之路     

克氏螯虾染色体研究

本文以克氏螯虾精巢为材料，用改良常规气干法进行染色体制片并显微照相，观察结果表明，克氏螯虾精母细胞染色体数为９４，中期染色体呈颗粒状。     

克氏螯虾的开发前景及养殖技术

克氏螯虾 ,学名克氏原螯虾 ,俗称龙虾。原产北美洲 ,现主要分布于长江中下游地区。1　开发前景1 .1　蛋白质含量高 ,具有较高的营养价值克氏螯虾肉味鲜美 ,营养丰富 ,蛋白质含量达1 6%～ 2 0 % ,干虾米蛋白质含量高达 5 0 %以上 ,高于一般鱼类 ,超过鸡蛋的蛋白质含量 ,是有待开发利用的水产动物资源。1 .2　适应性广 ,适宜于人工养殖克氏螯虾对水质要求不严 ,在我国大部分地区的江河、湖泊、池塘、水渠、水田、沼泽地等淡水水体均能生存 ,适应能力很强。同时 ,克氏螯虾苗种易繁育 ,可自繁、自育 ,不需复杂的设备 ,且饲料容易解决 ,为普及人…     

克氏原螯虾肌肉营养成分分析与评价

用常规方法对克氏原螯虾肌肉营养成分进行了分析测定,结果表明:克氏原螯虾粗蛋白含量和粗脂肪含量分别占鲜重的18.02%、2.05%;其蛋白质中含17种氨基酸,总量为17.13%,其中有8种必需氨基酸;必需氨基酸占氨基酸总量的48.86%.鲜味氨基酸占35.26%,必需氨基酸的比例超过FAO/WHO的标准;第一限制氨基酸是蛋+胱氨酸,第二限制氨基酸为缬氨酸;对脂肪酸的分析测得有15种脂肪酸,其中多不饱和脂肪酸占43.40%,EPA+DHA为3.69%.     

淡水小龙虾捕捞和保活装运技术

小龙虾（ Procambarus clarkii ）养殖者如缺乏捕捞小龙虾实用技术,会严重影响经济效益的提高,有的甚至还造成很大损失。产地销售往往效益较低,掌握活体装运技术,远离产地销售,可大大提高经济效益,应引起足够重视。     

小龙虾与河蟹池塘混养技术

为了探索小龙虾与河蟹生态健康养殖模式,提高池塘养殖产量和经济效益,笔者于2006年～2008年在洪湖市滨湖河蟹板块养殖基地进行了小龙虾与河蟹生态健康养殖试验示范,取得了良好的经济效益。平均亩产小龙虾156kg,河蟹115kg,亩产值6932元,每亩纯利4500元。     

克氏螯虾的生物学和生态养殖模式

克氏螯虾 (Procambarusclarkii) ,英文名Redswampcrayfish ,俗称龙虾、海虾等 ,是淡水经济虾类 ,因肉味鲜美 ,价格便宜而广受人们欢迎。现将所收集到的基本情况 ,结合我国水产养殖的实际 ,对其进行简单的介绍。1　概述1 1　基本特征克氏螯虾在分类上属节肢动物门 ,甲壳纲 ,软甲亚纲 ,十足目 ,刺蛄科。原产于北美 ,1918年被引入日本 ,192 9年经日本引入中国 ,经几十年的扩散 ,已形成全国性的分布 ,成为常见的淡水经济虾类。它适应性极广 ,具有较广的适宜生长温度 ,在水温为10～ 30℃时均可正常生长发育。亦能耐高温严寒 ,可耐受 4 0℃以上的…     

盐度和碱度对克氏原螯虾的联合毒性试验

用寇氏法(Karber法)研究了盐、碱对克氏原螯虾(Procambarusclarkii)的急性毒性作用,并采用相加指数法(Mark-ing指数法)研究了盐碱联合作用对克氏原螯虾的影响。结果表明:盐度对克氏原螯虾24h、48h、72h、96h的半致死浓度(LC50)分别为31.74g/L、27.21g/L、26.45g/L、26.09g/L,其安全浓度是6.00g/L。碱度对克氏原螯虾24h、48h、72h、96h的半致死浓度分别为12.00g/L、10.64g/L、8.36g/L、7.58g/L,其安全浓度是2.51g/L。盐碱在1:1毒性单位混合后,对克氏原螯虾的作用效果在不同时间段均表现为一定的拮抗作用。     

淡水龙虾的稻田养殖技术

龙虾学名克氏螯虾，属于节肢动物门。甲壳纲，十足目，龙虾科。目前，全国大多数地区都有龙虾生存，该种属温热带淡水虾类，适应能力强，繁殖率高，食性杂，生长快，抗病，耐高温，耐低氧，离水数小时不会死亡。龙虾肉味鲜美，营养丰富，脂肪含量较低，可食部分达40％以上。鉴于近几年野生龙虾遭到酷捕滥捞，数量急剧下降，为解决这一状况，从2005年开始。我站进行了稻田养殖龙虾试点工作，并取得了一定的成绩。通过实验，我总结了稻田养殖龙虾工作中应注意的几个关键性问题，现就这几个问题将养殖技术简述如下：     

克氏原螯虾对盐度适应性试验

对克氏原螯虾仔虾采用6个不同的盐度进行了盐度突变试验,2个试验组的初始盐度为2,探讨克氏原螯虾仔虾对盐度适应性。盐度突变试验结果显示,克氏螯虾仔虾对盐度为10以下具有较强的适应性。渐变试验显示,克氏螯虾仔虾的存活率与盐度调整周期有关,3d为1次的调整周期优于2d调整周期。因此,在低盐度水平开展克氏螯虾盐度驯养是可行的。     

克氏原螯虾形态参数关系的初步研究

对594尾(体长1.75~10.6 cm)克氏原螯虾的全长、体长、头胸甲长和体重等进行了测量分析。着重研究了体重与体长的关系,得到的关系式为:W♂=0.0299×Lb3.4925(r2=0.9818),W♀=0.0438×Lb3.1697(r2=0.9869)。同时还推断得出体长6.0~6.5 cm是克氏原螯虾的最适捕捞规格。