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1.
基于成像声呐的鱼类三维空间分布 总被引：1，自引：0，他引：1
针对海洋牧场中鱼群的三维空间分布问题,本研究提出一种利用成像声呐进行位置计算的方法。将成像声呐固定在船舷外侧的水下,并保证波束发射方向和声呐移动方向一致,通过走航的方式采集水下鱼群信息。首先对采集的原始数据进行图像处理,包括图像构建、背景去除、目标提取等,然后利用基于交互式多模型联合概率数据关联算法对水下目标进行关联处理,得到同一个目标在声呐水平视场中不同帧图像中的对应关系,在此基础上根据连续两帧图像中目标位置关系计算目标的空间坐标,最后结合关联算法获得多目标在三维空间中的运动轨迹以及深度分布情况。研究表明,本方法可以有效获取鱼群在水下的三维运动轨迹及其分布情况,这将为鱼类行为分析以及海洋牧场的资源评估提供技术支持。 相似文献
2.
为准确、高效评估养殖网箱场内鱼群数量，科学指导网箱养殖，提出了一种基于前视声呐的养殖网箱内鱼群数量统计方法。方法应用时，以声呐图像处理技术为基础，首先以目标网箱内养殖鱼类在消声水池实验室的声学标定结果为依据，对前视声呐测量声图进行单个鱼体的声学图像阈值划分；其次凭借云台控制声呐旋转，对围栏区域进行遍历探测，随后将声学标定结果确定的阈值作为划分依据，将不同角度所测声学图像中鱼类进行划分、统计，估算得到整个养殖网箱内的鱼类数量；最后结合探测角度以及位置信息，得到网箱养殖区域内的鱼类空间分布特征，用于指导渔民进行后续的网箱养殖。此方法在舟山青浜岛大黄鱼养殖网箱中得以应用。结果显示：该方法估计得到的养殖网箱内大黄鱼数量与人工评估结果基本一致，经多次计算，平均相对误差仅为2.45%,且实现过程更加高效、便捷。本研究能够有效为养殖网箱提供鱼类数量信息，为亟待进行鱼类数量监管的网箱养殖产业提供科学、可靠的数量统计方法，具有广泛的应用场景。 相似文献
3.
多波束渔用声呐是海洋渔业实现高效、精准和选择性捕捞的重要工具。为了系统分析多波束渔用声呐探测性能及主要制约因素对作用距离的影响,针对圆柱形阵多波束渔用声呐,采用水声学系统仿真的方法,分别对主要为噪声和混响环境下的渔用声呐探测性能进行分析,对不同海况下噪声不同目标强度鱼群的探测性能进行比较,分析窄带系统和宽带系统降低混响的能力,并对噪声和混响混叠环境下的渔用声呐探测性能进行仿真分析;最终,从系统设计、发射方式、接收方式等多个角度提出提高渔用声呐探测性能的方法,为远距离、高分辨率多波束渔用声呐的研制提供改进的方向。 相似文献
4.
为实现藻类的自动计数,以小球藻为对象,提出一种基于荧光效应和调色板均衡化的小球藻自动计数方法。首先对小球藻荧光显微图像进行预处理,将真彩色小球藻荧光图像转换为256色图像,再采用调色板均衡化算法增强小球藻荧光图像对比度,并利用基于调色板的阈值分割算法将目标藻类与背景进行分割,同时进行计数。结果表明,该计数方法能够避免杂质影响,直接对藻类彩色图像进行图像增强和阈值分割,可以增强图像对比度,避免彩色图像灰度化过程中图像信息损失;采用连通区域标记方法结合连通区域的大小识别低重叠度藻类,可降低重叠藻类对计数结果的影响,从而提高小球藻的计算准确度。研究表明,该方法实现了针对藻类彩色图像的自动计数,且对小球藻的计数精度准确率达到95%以上,高于只使用灰度图像计数的方法。 相似文献
5.
为应用超声组织定征纹理分析方法判断鲟鱼性腺成熟度,首先对17尾雌性杂交鲟进行性腺成熟度检测鉴定,其中7尾成熟,5尾未熟,5尾过熟,再应用超声组织定征分析法对上述鲟鱼性腺成熟、未熟、过熟的超声检测图像分别进行灰度特征值计算,选取了角二阶距、相关度、熵、逆差距、对比度5个特征值,定量分析了鲟鱼三个性腺发育期的超声图像的区别,确定了超声组织定征纹理分析方法判断鲟鱼性腺成熟度的可行性。 相似文献
6.
《南方水产科学》2021,(4)
为快速确定拖网深度、提高捕捞效率、降低渔业生产成本,文章根据声呐设备元数据(Metadata)提出一种提取指定鱼类目标最佳捕捞深度的方法。声呐设备元数据结构较为复杂且包含大量与目标捕捞对象无关的冗余数据,该研究通过分析简化了原始数据,计算和提取出海底深度、目标强度等信息,根据目标渔业资源类型确定有效数据范围及噪声数据范围,过滤噪声数据后以统计图形式展示有效数据,统计各个深度下的目标渔业资源量,构建深度与目标渔业资源量的关系,由多种方法计算并预测最佳捕捞深度。结果显示,在实验数据调查区域内,磷虾(Euphausia superba,目标强度-69.5～-40.8 dB)的最佳捕捞深度为172.9～187 m。由一段时间内某海域中探测到的声呐数据,可快速计算出该海域内目标渔业资源的最佳捕捞深度。 相似文献
7.
投放人工鱼礁作为海洋牧场建设的重要环节，其投放质量评估工作日益受到重视。为实现大范围的人工鱼礁三维信息的自动识别与提取，提升人工鱼礁量化评估的质量，提出了一种基于Ransac算法的多波束点云人工鱼礁提取方法。该方法首先利用多波束声呐获取点云，在对点云进行分割、去噪等预处理后，利用Ransac算法将点云分为内外点集，内点集近似拟合为海底平面，外点集为人工鱼礁。在浙江嵊泗马鞍列岛某礁区进行了相关试验，实现了整体和单体鱼礁的提取，提取正确度达94.79%,完整度达91%,能够较好地提取鱼礁的三维形态、位置、尺寸、高度、空方等信息。研究表明，本方法可以大范围地应用于各型人工鱼礁目标投放效果的量化评估。 相似文献
8.
本研究以鲟鱼(Acipenser sinensis)肉为原料,通过正交实验对鲟鱼鱼糜的漂洗工艺进行了优化,对鱼糜漂洗前后的蛋白质含量及其组成、水分分布、凝胶性能等进行了研究。结果显示,鲟鱼鱼糜的最佳漂洗工艺为：水漂洗1次,盐水漂洗1次,盐的质量分数为0.25%,漂洗时间为1 min。鲟鱼鱼糜经漂洗后,其盐溶性蛋白比例显著升高(P<0.01);鱼糜中的水分受到的束缚力增加,自由度减小,形成了更为致密的凝胶网状结构;破断力、凹陷距离、凝胶强度、持水力、白度等表征凝胶性能和鱼糜品质的指标明显提升。研究表明,采用恰当的漂洗工艺可显著提高鲟鱼鱼糜的品质。 相似文献
9.
10.
金枪鱼属(Thunnus)鱼类是我国远洋渔业极为重要的渔获资源, 其表型纹理信息不仅具有鱼种的特异性, 而且可作为分类的科学依据。传统鱼类纹理特征分析主要是定性描述分析, 而计算机视觉技术可为鱼类纹理特征提供定量分析数据。因此, 本研究通过计算机视觉对 3 种金枪鱼图像进行预先定位基准点, 通过移动基准点确定纹理特征区域并自动截取。对纹理图像进行灰度转换和灰度量化处理, 量化的灰度图像进行灰度共生矩阵计算, 并对灰度共生矩阵进行归一化处理。通过归一化的灰度共生矩阵计算出 6 个纹理指标, 并分析纹理指标的距离和方向的变化趋势, 通过因子分析研究金枪鱼纹理指标。研究结果表明, 通过计算机视觉的纹理分析, 3 种金枪鱼纹理指标提取效果较好, 其纹理指标在距离值为 4 时, 变化趋势趋于稳定, 而 3 种金枪鱼的纹理指标方向变化, 其均值方向具有代表性。3 种金枪鱼的因子分析, 第 1 主成分贡献率为 81.10%, 表明提取的 6 个纹理指标意义较大且效果较好。 以期为金枪鱼智能识别奠定前期基础, 也为其他鱼类表型纹理研究提供借鉴和参考。 相似文献
11.
Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean 
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下载免费PDF全文 The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna. 相似文献
12.
In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg. 相似文献
13.
Liping Li Rui Wang Wanwen Liang Xi Gan Ting Huang Yan Huang Jian Li Yunliang Shi Honglin Luo Ming Chen 《广西水产科技》2014,(1)
Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China. 相似文献
14.
15.
Growth hormone (GH) and reproduction: a review 总被引：5，自引：0，他引：5
Florence Le Gac Odile Blaise Alex Fostier Pierre-Yves Le Bail Maurice Loir Brigitte Mourot Claudine Weil 《Fish physiology and biochemistry》1993,11(1-6):219-232
Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations. 相似文献
16.
Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL?1 (1.25 ng well?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation. 相似文献
17.
Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection 下载免费PDF全文
下载免费PDF全文 G Sharon M Pimenta‐Leibowitz M C L Vilchis N Isakov D Zilberg 《Journal of fish diseases》2015,38(1):67-74
Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality). 相似文献
18.
William King V David L. Berlinsky Craig V. Sullivan 《Fish physiology and biochemistry》1995,14(6):489-500
Plasma estradiol-17 (E2), testosterone (T), 17,20-dihydroxy-4-pregnen-3-one (DHP) and 17,20,21-tri-hydroxy-4-pregnen-3-one (20-S) levels were measured by radioimmunoassay (RIA) in white perch (Morone americana) and white bass (M. chrysops) that were induced to undergo final oocyte maturation (FOM) with human chorionic gonadotropin (hCG). Plasma DHP levels increased in females of both species in association with oocyte germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) and decreased thereafter. Plasma 20-S levels also increased with oocyte GVM in white bass, but were several-fold lower than DHP levels. Circulating E2 and T levels were greatest during GVM and GVBD in both species and decreased to low levels during oocyte hydration and ovulation. Follicles from white perch and white bass which received a priming injection of hCG in vivo, produced both DHP and 20-S in vitro after exposure to hCG and their oocytes underwent GVBD. Ovarian incubates from unprimed fish of either species produced only E2 and T and their oocytes did not complete GVBD. Oocytes from unprimed bass, but not perch, matured when follicles were exposed to hCG in vitro. Both trilostane and cycloheximide blocked in vitro production of DHP and 20-S and oocyte GVBD by white perch follices. DHP and 20-S were equipotent inducers of FOM in the GVBD bioassay. None of several other structurally-related steroids tested were effective within a physiological range of concentrations. These results indicate a role for DHP and 20-S in the control of FOM in white perch and white bass. 相似文献
19.
Cardiac,ventilatory and metabolic responses of two ecologically dissimilar species of fish to waterborne cyanide 总被引：1，自引：0，他引：1
Changes in heart rate, ventilatory activity and oxygen consumption were determined in trout (Salmo gairdneri) and brown bullhead catfish (Ictalurus nebulosus) during exposure to a steadily increasing concentration of waterborne cyanide selected to produce death in 8–9 hours for each species. The lethal cyanide concentration for the bullheads was an order of magnitude higher than for trout. Trout developed an immediate and gradually increasing bradycardia throughout the exposure period. Cyanide produced tachycardia in the bullhead followed by a gradual onset of bradycardia as the concentration of cyanide was raised. Pericardial injection of atropine (a muscarinic cholinergic antagonist) indicated that bradycardia in the trout was due initially to increased vagal tone but later due to the direct effect of cyanide on the heart. Hyperventilation in the trout persisted throughout the exposure period, although the rate and amplitude fluctuated and was variable between individual fish. During the last hour of exposure (highest cyanide concentration), ventilation was characterized by rapid, shallow breaths followed by a sudden respiratory arrest. The bullheads exhibited hyperventilation during the first 3 hours of exposure followed by a gradual, linear drop in ventilation rate and amplitude until death occurred. Cardiac and ventilatory responses in both species were attributed to stimulation of central and peripheral chemoreceptors by cyanide. Evidence is presented which suggests the initial response in the bullheads was due, at least in part, to gustatory stimulation by the cyanide. Oxygen consumption of the trout remained above pre-exposure levels for the majority of the test period. Oxygen consumption in the bullhead paralleled the changes in heart and ventilatory rates. Whole-body lactate levels of fingerlings of both species during cyanide exposure were measured to estimate the extent of anaerobiosis. Whole-body lactate levels were much greater in the bullheads than the trout, indicating a higher capacity for anaerobiosis, possibly due to a greater fuel supply. Overall, the trout responded to cyanide in a manner similar to that produced by environmental hypoxia whereas the bullheads experienced a gustatory stimulus which masked the hypoxia-like response. 相似文献
20.
The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg–1 fish·h–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g–1·ml–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min–1·g–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min–1·g–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated. 相似文献