共查询到19条相似文献，搜索用时 171 毫秒
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研究了洞穴、角落、空旷3种生境下,克氏原螯虾与中华绒螯蟹混养的存活率和残肢率,以探究两者的种间竞争情况;采集在室外池塘下,虾蟹混养和克氏原螯虾单养的克氏原螯虾收获量、回捕率,分析自然条件下两者的种间竞争情况。结果显示,混养时克氏原螯虾在洞穴型和空旷型生境下,存活率显著提高,残肢率显著下降;而中华绒螯蟹的存活率则显著下降,在洞穴型生境下残肢率显著提高;在角落型生境下,虾、蟹混养会导致克氏原螯虾存活率显著降低,对中华绒螯蟹的存活率无显著影响;在野外池塘条件下,虾蟹混养组最终的克氏原螯虾收获量和克氏原螯虾单养组并无显著性差异。 相似文献
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栖息环境对克氏原螯虾抱卵量的影响 总被引：2，自引：0，他引：2
6口池各放克氏原螯虾100尾,分别给予不同的栖息环境,对人工创造生态环境对克氏原螯虾抱卵量的影响进行了对比研究.结果认为池塘具备良好的土质洞穴环境可明显地提高克氏原螯虾的繁殖力. 相似文献
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文章通过观察人工养殖环境下,克氏原螯虾(Procambarus clarkiaii)在堆积的竹筒和PVC管2种类型洞穴中的分布情况,分析比较了克氏原螯虾对2种洞穴的选择适应性和空间分布占比规律,不同洞穴内外的雌雄比例分布规律,及单一洞穴内虾的数量分布及雌雄比例规律。实验结果表明,克氏原螯虾喜栖息躲藏于洞穴中(A组83.47%,B组89.87%),尤其喜栖息躲藏于竹筒洞穴中[B组竹筒(71.80%)和PVC管(11.63%)]。垂直摆放洞穴的上下位置会影响克氏原螯虾分布,克氏原螯虾更喜欢在中下层和下层洞穴中躲藏,其分布数量由下而上依次降低。克氏原螯虾具有一雄多雌同居一穴的现象,不同垂直空间雌雄分布比例没有明显规律,但雌雄比最高分别出现在A组的最下层(3.43∶1)和B组竹筒洞穴的最上层(2.86∶1)。 相似文献
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不同开口饵料对克氏原螯虾幼虾发育及消化酶活性的影响 总被引：3，自引：0，他引：3
实验采用丰年虫无节幼体、草鱼鱼糜、水蚯蚓、1号人工配合饲料和2号人工配合饲料为克氏原螯虾的开口饵料,观察幼虾存活率和生长情况。经过40d的培育,对幼虾的胃蛋白酶、胰蛋白酶、淀粉酶和脂肪酶的活力进行测定。结果表明：投喂丰年虫无节幼体的实验组幼虾存活率最高,为75,增重率和增长率也最大,分别为4746.00和171.00。幼虾的胃蛋白酶活性与投喂的饵料密切相关,投喂丰年虫无节幼体组幼虾的胃蛋白酶和胰蛋白酶活性分别为2.18U/mgprot和0.96U/mgprot,极显著高于投喂草鱼鱼糜实验组。实验的5种开口饵料中,丰年虫无节幼体是克氏原螯虾幼虾的最佳开口饵料。摄食丰年虫无节幼体可能提高了主要消化酶的活性,从而促进了克氏原螯虾幼体的生长。 相似文献
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在室内小型水体、户外中型水体及池塘大型水体3种环境下同步和异步养殖克氏原螯虾,对比了存活率、残肢率和质量变异系数等指标。小型、中型水体同步组的残肢率均显著低于异步组(P值分别为0.007、0.016);中型水体同步组的存活率显著高于异步组,P=0.006;中、大型水体同步组螯虾质量变异系数均小于异步组(P值分别为0.015、0.002)。结果显示,克氏原螯虾存在先期领域所有权现象,即"有产者原则"。人工养殖中异步放养虾苗违背该原则,易增加螯虾群体自相残杀而导致存活率下降;同步放养则符合"有产者原则",有利于降低螯虾种内格斗。试验结果为解决高密度水产养殖中克氏原螯虾自相残杀而导致的减产提供科学依据。 相似文献
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克氏原螯虾又称红色沼泽螯虾、小龙虾或克氏螯虾,目前在我国开展克氏原螯虾人工增殖的养殖者逐年增加.为了便于养殖者更好地开展大水面人工增殖克氏原螯虾,笔者对近年来江西环鄱阳湖区克氏原螯虾人工增殖实践进行了总结,以供参考. 相似文献
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Shiyu Jin Lisa Jacquin Yan Ren Jixin Yu Wei Li Sovan Lek Jiashou Liu Zhongjie Li Tanglin Zhang 《Aquaculture Research》2019,50(3):934-943
Overfeeding in aquaculture can lead to suboptimal growth and increased production costs. Red swamp crayfish, Procambarus clarkii, is one of the most noteworthy species cultured in China, but little information is available on the optimal feeding levels of this species, especially in ponds cultured with macrophytes. In this study, we tested the effects of five different feeding levels (20%, 40%, 60%, 80% and 100% satiation) of an artificial diet on growth performance and muscle composition of juvenile P. clarkii in 15 concrete ponds cultured with the macrophyte Hydrilla verticillata (three replicates for each treatment). The results showed that growth performance decreased only when feeding levels were below 60% satiation. Muscle composition analysis revealed that the moisture and ash contents of muscle did not vary significantly with feeding levels but that the lipid and protein contents of muscle significantly decreased when P. clarkii was fed to 40% satiation. Stable isotope analysis suggested a shift in crayfish diets to easily available H. verticillata when feeding levels decreased. With this study, we hope to encourage crayfish farmers to reduce feeding levels and increase natural food items such as macrophytes in cultured ponds to maximize crayfish yields and reduce production costs. 相似文献
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《Journal Of Applied Aquaculture》2013,25(3):31-40
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. 相似文献
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Paul B. Brown Michael L. Hooe William G. Blythe 《Journal of the World Aquaculture Society》1990,21(1):53-58
Culture potential of Orconectes virilis , the northern or fantail crayfish, was evaluated in deep ponds and simulated shallow ponds during the summer and fall. Adult crayfish were stocked in the deep ponds in October and known numbers of juvenile crayfish were stocked in the shallow ponds in May. Triplicate groups of crayfish in each system were either not fed (negative control) or fed corn silage or wheat straw. Production in either system was not significantly different between treatments, but production in the shallow tanks (790 kg/ha) was almost double that observed in the deep ponds (401 kg/ha) and may have been due to different stocking strategies. Juvenile crayfish were generally of minimal marketable size at the end of one growing season. The shallow tanks were restocked in October and drained in March to evaluate overwinter survival in this type of system. Survival averaged 78.9% for both males and females, and most (97.1%) age 1 females were carrying eggs. 相似文献
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Density reduction, supplemental feeding, and a combination of two treatments were evaluated as means to alleviate stunting of red swamp crayfish Procambarus clarkii in earthen ponds. Mean total yield of crayfish in low density control ponds averaged 1,218 kg/ha and was 1.5 to 2 times higher (P≤ 0.05) than either the high density control or treatment ponds. Mean individual harvest weight of crayfish averaged 15.1 g and did not differ among treatments. Mean total yield of crayfish in ponds receiving supplemental feed was 32% higher than non-fed ponds (P≤ 0.05). Mean total yield and size of crayfish at harvest from reduced and non-reduced treatments did not differ. Density reduction and supplemental feeding implemented in early April did not increase individual crayfish weight to the commercially desirable size of 20 g. 相似文献
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Is it a hindrance for an invasive aquatic species to spread across scattered habitat patches? 
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下载免费PDF全文 Anne Tréguier Jean‐Marc Roussel Nadège Bélouard Jean‐Marc Paillisson 《水产资源保护:海洋与淡水生态系统》2018,28(3):610-618
1. Despite their importance for aquatic biodiversity, ponds are among the most vulnerable freshwater habitats. Owing to their isolation in terrestrial environments, ponds are expected to be relatively well protected from biological invasions, but this depends on many factors. 2. The purpose of this study was to examine the influence of a range of variables (water quality, habitat, and landscape attributes) on the colonization of discrete ponds by a widespread aquatic invader, the red swamp crayfish Procambarus clarkii, which can disperse overland. 3. Investigations were conducted in two networks of ponds, each located in close proximity to a large invaded marsh. The two marshes under study differed in the length of time since the crayfish were introduced. 4. The proportions of colonized ponds and crayfish abundances were moderate in both networks, but higher in the network that had been invaded first. In both networks the distance to the marsh was the main predictor of pond colonization, considering similar energy costs to cross aquatic and terrestrial habitats for the recently invaded network, but assuming that dispersal was 25 times costlier across the terrestrial matrix than via streams for the earlier invaded network. Pond characteristics had no influence on crayfish occurrence in either network. Furthermore, predictions of pond invasion were lower for the recently invaded network. 5. The importance of the distance to the marsh indicates that natural dispersal was the main process of pond colonization by crayfish. Findings also suggested that overland dispersal was rare and costly. By contrast, streams were probably significant in facilitating crayfish dispersal. Differences between the two networks might arise from an invasion process still in progress in the recently invaded network. 6. From a management viewpoint, local actions are encouraged to prevent the spread of crayfish via streams. In addition, broader‐scale actions to mitigate other human disturbances would improve the outlook for pond biodiversity. 相似文献
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《Journal Of Applied Aquaculture》2013,25(3):83-90
Abstract Red claw crayfish, Cherax quadricarinatus, are perhaps the first tropical species of crayfish to be cultured commercially. Culture traits and high market value could allow semi-intensive culture. Feeding strategies used in extensive crayfish ponds in temperate climates may not be the most appropriate for semi-intensive culture systems where year-round growth is possible. The following study was conducted to evaluate differences between using a pellet-based system versus a pellet-plus-forage-based system. The study was conducted in 14 0.3-ha ponds on a commercial farm in Ecuador. Juvenile red claw (1-2 g) were stocked into all ponds at a rate of 4/m2. All ponds received pelleted shrimp rations at a rate of 3% per day. Seven ponds also received dried hay at a rate of 100 kg/ha/mo during the 3-month study. At harvest, red claw weights were similar (30-34 g), but survivals were significantly higher in ponds receiving pellets and hay (65%) than in ponds receiving pellets only (50%). Yields in pellet-fed ponds averaged 594 kg/ha, while red claw receiving pellets plus forage averaged 889 kg/ha. The addition of dried forage was thought to provide a larger variety of natural food organisms throughout a greater area of the pond bottom and provided additional substrate for dispersal and hiding. Addition of grasses from outside the pond is recommended over production of grasses grown within the pond. 相似文献
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Infection by intracellular bacterium in red claw crayfish, Cherax quadricarinatus (Von Martens), in Ecuador 总被引：2，自引：0，他引：2
An intracellular bacterium was detected on several occasions in commercial farms in Ecuador culturing red claw crayfish, Cherax quadricarinatus (Von Martens). Cases A, B and C presented mortality rates of 80%, 45% and 80%, respectively. Each incident occurred in grow-out ponds. Moribund crayfish were observed at the edge of the ponds in some cases. Affected crayfish presented no external differences from healthy ones, except their smaller size. Histological examination of affected red claw crayfish revealed that the cytoplasm of cells in the hepatopancreas, cuticular epithelium, and connective tissue of all organs had been replaced by massive granular and basophilic material. In the hepatopancreas, the tubules were intact but the intertubular connective tissue was replaced by Gram-negative microcolonies. Columnar cells in the cuticular epithelium also contained Gram-negative microcolonies and were necrotic. The heart and nerve cords also contained basophilic material. Transmission electron microscopy showed that the microcolonies consisted of a rod-shaped, obligately intracellular bacterium. The bacterium was delimited by a cell membrane that was composed of two electron-dense zones. Cells contained a single, compact, cytoplasmic condensation that was circumscribed by an electron-lucent halo. The bacterium replicated within the cytoplasm of host cells, which is pathognomic of rickettsiales infections. No host cell nuclei were infected. 相似文献
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Donald Wujtewicz Bernard R. Petrosky Dorene L. Petrosky 《Journal of the World Aquaculture Society》1997,28(3):249-259
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. 相似文献