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1.
Spermatozoa of common carp Cyprinus carpio are typically consist of a primitive head without acrosome, a midpiece with several mitochondria, a centriolar complex (proximal and distal centriole), and one flagellum. During an evaluation of the motility of common carp spermatozoa, we found spermatozoa with more than one flagellum and/or “double head” in three different individuals. This may be related to abnormal spermatogenesis. Ultrastructure and physiological parameters of spermatozoa were examined using light microscopy (dark field with stroboscopic illumination), transmission and scanning electron microscopy, and flow cytometry. The recorded pictures and videos were evaluated using Olympus MicroImage software. All spermatozoa with more than one flagellum had a larger head and shorter flagella. They occasionally demonstrated several cytoplasmic channels separating the flagella from the midpiece. Each flagellum was based upon its own centriolar complex, with the connection of the flagellum to the head always at a constant angle. The flagella always consisted of nine peripheral pairs and one central doublet of microtubules. Sperm exhibited a relative DNA content similar to that found in sperm from normal males, with higher coefficients of variation. Although similar abnormalities have been found in livestock, where they were described as a defect in spermiogenesis, no comparable results have been reported in fish. The frequency at which these abnormalities occurs, the fertilization ability of males with defects in spermiogenesis, the influence of these abnormalities on progeny in terms of ploidy level, and the occurrence of deformities warrant further investigation.  相似文献   

2.
Basic characteristics of the European smelt (Osmerus eperlanus) sperm are reported here for the first time. Smelt spermatozoa had a bullet-shaped head (1.42 μm length), a short midpiece and a long flagellum (27.72 μm). Two mitochondria were located along the flagella. The volume of smelt sperm was small (30-60 μl) and the duration of sperm motility was short (22 s in distilled water and 41 s in 20 mM sodium bicarbonate solution). Sodium chloride at concentrations ranging from 0-120 mM did not influence the percentage of motile spermatozoa but caused a steady increase in the duration of sperm movement. Potassium ions clearly reduced the percentage of motile sperm at a concentration of 10 mM. Spermatozoa were motile through a broad range of pH with an optimum from 7.5 to 8.5. Testicular spermatozoa had a different motility pattern compared to stripped spermatozoa (the latter exhibiting a reduction of motile spermatozoa by 30%, lower ALH and VCL and higher LIN and VSL). These results indicate that maturation of smelt spermatozoa occurring in sperm ducts is related not only to an increase of the percentage of motile spermatozoa but also to changes in the sperm motility pattern. Maintaining males with females resulted in stimulation of milt production. Our results indicate that European smelt sperm characteristics are similar to those of ayu (Osmeridae).  相似文献   

3.
The feeding events of wild animals have been widely researched in recent decades. The use of invasive methods to determine stomach contents in which the fish is killed can, however, be considered to be unjustifiable in the case of an endangered fish, such as the Japanese late. Here, we report on a method that can be used to verify feeding events of a fish species without the need for killing the fish through the use of a high-speed video camera and a three-axis micro-acceleration data-logger. High-quality images obtained by the video showed that the fish opens its mouth with a quick downward movement of the mandibles and ingests prey via suction feeding. The movement of the mandibles was also simultaneously recorded by changes in the three-axis accelerations obtained by the logger attached to the dorsum. We attached the logger with an automatic release system to the dorsum of one captive Japanese lates and two wild fish together with an acoustic transmitter and then released the fish in the Shimanto River in Japan. After retrieving the logger, the movement records of the fish obtained by the three-axis accelerometer showed the same pattern of feeding events as those in captivity. A total of 13 feeding events at night and five during the daytime were obtained for the three fish during a total 129.7 h of recording.  相似文献   

4.
The objective of this study was to describe the morphometry and motility parameters of vendace (Coregonus albula) spermatozoa. Morphometric parameters of vendace sperm head and tail were of values similar to rainbow trout. The effects of pH, sodium, potassium and calcium ion concentrations on computer-assisted sperm analysis (CASA) sperm motility characteristics were tested. Vendace sperm was motile in a wide pH range of 6.0–10.5 with the optimum pH established at 9.0. Increases in potassium and calcium ions caused decreases in the percentage of motile sperm. The CASA parameters and erratic sperm movement pattern of vendace spermatozoa were similar to whitefish (C. lavaretus) sperm motility, suggesting that there is a coregonid-specific sperm motility pattern.  相似文献   

5.
A prototype remotely operated vehicle (ROV) is being developed for use in aquaculture. The initial task for which the ROV has been built is to carry video cameras to provide pictures of fish for automatic image analysis. This paper explains the constraints on the design of the ROV, arising from hydrodynamic and practical considerations, and how these have been accommodated. The results of tank tests and field trials are reported.  相似文献   

6.
To clarify factors reducing the motility and fertility of cryopreserved spermatozoa of the Japanese pearl oyster Pinctada fucata martensii, the structure of spermatozoa before and after cryopreservation was observed by scanning electron microscopy. Testicular spermatozoa were diluted with cryopreservation diluent (10% methanol+18% fetal bovine serum+72% sea water), and dispensed into 0.25-mL straws. The straws were cooled at a rate of approximately −20 °C/min to −50°C, and subsequently immersed in liquid nitrogen. Percentage motility of spermatozoa before cryopreservation was 69.9±4.2%, and that of cryopreserved spermatozoa was 24.0±1.8%, respectively. In cryopreserved spermatozoa, the percentage that lacked or had a deformed flagellum was 56.6±3.9%, while in fresh spermatozoa this was 8.7±2.0%. In cryopreserved spermatozoa, the percentage of deformed acrosomes was 76.6±5.2%, while in fresh spermatozoa this was only 0.9±0.3%. Cryopreserved spermatozoa with a normal acrosome and flagellum were only 15.4±3.5% of those in fresh spermatozoa. These results indicate that lesion of the flagellum and deformation of the acrosome occurred through the cryopreservation procedure, and both types of damage lead to loss of the motility and fertility in thawed spermatozoa.  相似文献   

7.
Behavioral variations of a school of fish (Carrasius auratus) in a tank were monitored using computerized vision while the fish were subjected to hypoxia stress conditions. Two video cameras viewed the tank, one from the side through a transparent wall and one from above. The images were processed by a PC-based image processing algorithm which provided three coordinates of the school's center of gravity, with the standard deviations of each coordinate, and the projected spatial distribution of the fish. Stressed fish differed from controls with the following behavioral responses: (i) the center of gravity moved upwards and horizontally away from the transparent wall; (ii) swimming speed was apparently reduced; (iii) there were strong fluctuations in all three directions associated with spreading and contracting of the school; (iv) the periodic amplitude of the motion in the vertical direction increased. This study might evolve into an automatic stress warning technique for fish farms, based on alterations in the behavior of fish when stressed.  相似文献   

8.
All evidence to date suggest that sperm motility is the primary determinant of fertilization success in externally fertilizing fish species. Ovarian fluid, which comprises 10–30% of the total egg volume in salmonids, enhances sperm motility with respect to swimming speed, trajectory and the duration of movement. It was recently demonstrated that there is individual variability in sperm motility enhancing potential of ovarian fluid of particular females. In the present study we examined the effect of particular ovarian fluids collected from 31 females on the sperm motility parameters of one male of rainbow trout (Oncorhynchus mykiss) using computer-assisted sperm analysis (CASA). During our experiment we also monitored the pH of ovarian fluid. We found that particular fluids differed in the ability to activate spermatozoa; sperm remained immotile in four fluids and exhibited 50–100% motility in 27 samples. The percentage of motile sperm, velocity and duration of movement positively correlated with ovarian fluid pH (r2 = 0.34–0.62). These data strongly suggest that the pH of the ovarian fluid is the primary determinant of sperm motility in rainbow trout under natural conditions of fertilization.  相似文献   

9.
The definition of a remote system in the monitoring of fin fish growth rate and shape change relies on the development of the appropriate optical ranging system and the automation of data collection. Among the available technologies, a dual camera optical ranging system is presented as the most suited for fish size remote estimation. Images are collected via a submergible low-priced dual camera module connected to a portable waterproof PC equipped with two frame grabbers. Two images are synchronically collected and, with the system parameters (focal length of both cameras, distance between the two cameras, vertical and horizontal tilt and relative rotation of the two cameras), are used to collect data of fish size and shape. A Neural Network is built to correct the error of measurement. A geometric algorithm is developed to filter fish images and elliptic Fourier analysis of automatically collected fish outline coordinates is proposed as a tool of shape analysis. For all other fish orientations, landmarks (homologous points) are collected on fish outlines and evident structures: landmark configurations relative to each fish are then rotated using the system parameters. The proposed system can be used in the monitoring of sea-based fish farming facilities, especially those which are permanently submerged, reducing mortality and stress due to fish sampling and limiting divers intervention. By its application in the study of wild population, the system can be useful in the characterization of fish communities and population dynamics, supporting traditional visual census techniques with a tool which allows for continuous, remote and automatic data collection.  相似文献   

10.
Marine current energy converters such as tidal and riverine turbines have the potential to provide reliable, clean power. The risk of collision of fishes with marine energy turbines is not yet well understood, in part due to the challenges associated with observing fish at turbine sites. Turbidity and light availability can limit the effectiveness of optical sensors like video cameras, motivating the use of acoustic cameras for this task. However, challenges persist in collecting and interpreting data acquired from acoustic cameras. Given the limited number of turbine deployments to date, it is prudent to draw on the application of acoustic cameras to monitor fish in other scenarios. This article synthesizes their use for other fisheries applications to inform best practices and set realistic expectations for the results of acoustic camera monitoring at turbine sites. We discuss six key tasks performed with acoustic cameras: detecting objects, identifying objects as fish, counting fish, measuring fish, classifying fish taxonomically and analysing fish behavior. Specific challenges to monitoring fish at turbine sites are discussed. This article is intended to serve as a reference for researchers, regulators and marine energy developers on effective use of acoustic cameras to monitor fish at turbine sites. The studies detailed in this article provide evidence that, in some scenarios, acoustic cameras can be used to inform the risk of fish collision with marine energy turbines but doing so requires careful study design and data processing.  相似文献   

11.
《Aquacultural Engineering》2007,36(3):218-227
The definition of a remote system in the monitoring of fin fish growth rate and shape change relies on the development of the appropriate optical ranging system and the automation of data collection. Among the available technologies, a dual camera optical ranging system is presented as the most suited for fish size remote estimation. Images are collected via a submergible low-priced dual camera module connected to a portable waterproof PC equipped with two frame grabbers. Two images are synchronically collected and, with the system parameters (focal length of both cameras, distance between the two cameras, vertical and horizontal tilt and relative rotation of the two cameras), are used to collect data of fish size and shape. A Neural Network is built to correct the error of measurement. A geometric algorithm is developed to filter fish images and elliptic Fourier analysis of automatically collected fish outline coordinates is proposed as a tool of shape analysis. For all other fish orientations, landmarks (homologous points) are collected on fish outlines and evident structures: landmark configurations relative to each fish are then rotated using the system parameters. The proposed system can be used in the monitoring of sea-based fish farming facilities, especially those which are permanently submerged, reducing mortality and stress due to fish sampling and limiting divers intervention. By its application in the study of wild population, the system can be useful in the characterization of fish communities and population dynamics, supporting traditional visual census techniques with a tool which allows for continuous, remote and automatic data collection.  相似文献   

12.
The aims of this study were to describe the fresh spermatozoon ultrastructure using scanning and transmission electron microscopy and to improve the sperm cryopreservation methodology for the freshwater fish pirapitinga Brycon nattereri. Extenders (BTS? and NaCl), straw volumes (0.5 and 4.0 mL), thawing temperatures (30 and 60 °C) and activating agents (0.29% NaCl and 1% NaHCO3) were tested. Methylglycol was used as a cryoprotectant agent and sperm was frozen in nitrogen vapour (dry‐shipper). Post‐thawed sperm motility rate, motility quality (score 0=no movement; 5=rapidly swimming spermatozoa), duration of motility and spermatozoon morphology were evaluated. Fresh spermatozoon was 35.06 μm long, the head was ovoid (2.00 × 1.22 μm) with no acrosome, the midpiece was 2.15 μm long and the flagellum was 30.90 μm long with the typical 9+2 axoneme arrangement. Post‐thawed sperm motility rate (70–79% motile sperm), motility quality (score 3.1–3.7) and morphology (9.3–11.6% abnormal spermatozoa) were not affected by any of the parameters tested. The duration of sperm motility was longer when triggered in 1% NaHCO3 (392–1031 s) compared with 0.29% NaCl (144–338 s). Brycon nattereri sperm cryopreserved under the conditions described above yields over 70% motility and should last long enough to fertilize oocytes, even after 2 years of freezing.  相似文献   

13.
日本沼虾第一触角感受器的形态和分布   总被引：1，自引：0，他引：1  
本研究应用扫描电子显微镜对日本沼虾第一触角触鞭上各种感受器的分布情况和形态结构进行了观察。结果表明,雌性和雄性日本沼虾触角感受器在种类、形态和分布上均相似。第一触角分为内、外两鞭,外鞭上具有附鞭。触角上共有四种感受器,分别为化感刚毛（或称嗅毛）、I型简单刚毛、II型简单刚毛和有齿刚毛。化感刚毛上端柔软,顶端无孔,仅着生于附鞭的凹槽内。其它三种感受器在内外两鞭上均有分布。I型简单刚毛通体光滑,顶端逐渐变细,具一顶孔,常伴生II型简单刚毛和有齿刚毛,但长度比后两种的短;II型简单刚毛基部光滑,顶端被鳞片覆盖,且具复杂的孔结构;有齿刚毛有大小两种类型,表面上长有许多齿状突起,齿状突起主要分布于刚毛近顶端1/2~1/3区域内,近基部光滑无齿状突起。有齿刚毛的顶端也被鳞片覆盖,也具复杂的孔结构,结构与II型简单刚毛十分相似。  相似文献   

14.
Our study assessed the efficiency of a formulated new extender in maintaining viability and morphological integrity of Colossoma macropomum spermatozoa under chilling storage. Semen was diluted in the test extender and BTS? (Beltsville Thawing Solution) and exposed to a short‐term storage at 4.6 ± 0.6°C for 96 hr. Both extenders were able to maintain 17% ± 8% motile spermatozoa by the end of experiment. Sperm dilution in test extender did not affect the morphologically normal cells (61% ± 6%) up to 48 hr of chilling, being higher than in BTS? (50% ± 6%) (p < 0.05). After 96 hr, samples kept in the test extender had 50% of normal spermatozoa, whereas those kept in BTS? presented only 38% of normal cells. Chilling storage increased the incidence of cells with strongly coiled flagella in BTS?. Our study is the first to evaluate in detail the spermatozoa morphology as indicative of C. macropomum semen viability. The new extender was able to protect the spermatozoa against increase in coiled flagellum injuries.  相似文献   

15.
The Ionic and Osmotic Factors Controlling Motility of Fish Spermatozoa   总被引：4，自引：0，他引：4  
This review presents actual knowledge about energetic, ionic, osmotic and gaseous control of fish sperm motility and its duration. Right after they are activated, fish spermatozoa of most species swim for a short period of time, in the range of one to several minutes. What determines the activation process? Is it due to the new ionic, gaseous and/or osmotic environment? Why is the duration of motility so short? Is it resulting from a fast exhaustion of energy stores (ATP, ADP, AMP, PCr) combined with the above-mentioned ionic/osmotic stress leading to morphological alterations? The motility criteria (flagellar beat frequency, head displacement velocity, flagellar waves morphology, etc.) used to characterize fish sperm movement and sperm flagella will be described. Most parameters change very rapidly during the brief motility period of fish sperm. Then will be considered the main environmental factors, ionic and/or osmotic signals, responsible of the activation of fish sperm motility. Then the metabolic compounds involved in cell energetics will be considered as their concentrations also rapidly change during the motility phase. An additional feature will then be discussed concerning the mechanisms by which fish sperm cell can be revived for a second motility round at the end of the first motility period. A model is proposed to explain how external osmolarity can control internal ionic composition, the latter being the key factor controlling flagellar activity.  相似文献   

16.
Five hormonal treatments with human chorionic gonadotropin (hCG) were tested for the induction of maturation and spermiation in male farmed eels. The main aim was to optimize previously used hormonal treatments to achieve shorter induction treatments, longer spermiation periods and/or higher sperm quality. Fish treated for just 3 weeks (treatment E) or until the onset of spermiation (treatment C) showed the worst results, while the treatment consisting of weekly administration of 1.5 IU hCG g?1 fish (treatment A) induced the highest percentage of spermiating males, the highest number of sperm samples and sperm volumes and densities similar to the rest of the treatments (B: half hormone dosage, or D: biweekly administration). Evaluation of the sperm quality was performed by computer‐assisted sperm analysis (CASA), considering the percentage of total motile spermatozoa, the percentage of fast and medium‐velocity spermatozoa, as well as different motility parameters. Sperm samples from A‐D groups showed between 44% and 54% motile spermatozoa, and between 10% and 15% fast spermatozoa, while samples from E‐treated males showed 0% motile cells. No significant differences were found in the spermatozoa straight line velocity (VSL), curvilinear velocity (VCL) or the angular velocity (VAP), neither spermatozoa beating cross frequency (BCF) between A–D groups.  相似文献   

17.
《水生生物资源》2000,13(5):341-347
A method for discriminating fish from debris in sonar counts of out-migrant salmonids was tested in the Trinity River, California. The method used induced fish movements to distinguish fish from drifting debris. Electricity and light served as stimuli and video and split-beam sonar were used to measure movements of fish (mainly juvenile chinook salmon) and debris (mainly tree leaves). Differences in fish and debris behavior were clearly observable with underwater video. Many fish darted or slowed and most fish dove, whereas debris drifted passively. Fish responded to the electric field inconsistently, and an apparent positive phototaxis was the most consistent response to stimuli. Lack of matched sonar and video observations of individual targets prevented direct testing of sonar’s ability to differentiate fish and debris in the Trinity River. However, analysis of sonar data from a similar situation in the Seton River, British Columbia, indicate that fish responses measured in the Trinity River by video were within the resolution of split-beam sonar. Split-beam position measurement error averaged ≤ 0.06 m within 5° of the acoustic axis, compared to a mean diving reaction of 0.11 m by salmonids observed with video. Proper transducer deployment, improved sonar analysis methods, and perfection of stimuli to elicit obvious and consistent fish responses are key to the success of this technique. With suitable development and validation, the stimulus-response method could become a useful tool for apportioning sonar counts among fish and debris.  相似文献   

18.
Hydropower structures hinder the movement and migration of fishes, impairing their life cycles. Additionally, downstream moving fish are often at risk of being injured during turbine passage. To improve hydropower production towards more fish-friendly techniques and management, knowledge on timing and extent of natural patterns of fish downstream movement is necessary. So far, migration behaviour of long-distance migrators such as eel or salmon has been well studied, but little is known about seasonal and diurnal movement patterns of nonmigratory species or medium-distance migrators. In this study, movement patterns of 39 fish species captured by stownets while transiting hydropower facilities in four impounded rivers were assessed and compared with the fish community composition directly upstream of the hydropower plants assessed by electrofishing. Strong differences between the fish community composition inhabiting the upstream sides of the dams and the fish detected in downstream passage were evident. In each study river, the downstream moving fish community composition differed significantly between spring and autumn. On average, significantly more fish were caught during the night (2.9 fish/hr) than during the day (1.3 fish/hr). Topmouth gudgeon, European grayling and pike-perch mostly moved downstream during the night, whereas roach, spirlin and bleak were the most frequent downstream moving fish during daytime. Downstream fish movement was positively related with turbidity, water temperature and discharge. The strong differences in seasonal and diurnal fish movement patterns suggest that fish damage can be strongly reduced by adaptive turbine and corridor management, for example by shutting down turbines at peak movements.  相似文献   

19.
《水生生物资源》1998,11(2):61-74
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20.
Abstract. Flagellates infesting the gills of freshwater fish are reviewed and Cryptobia branchialis Nie is differentiated from them. Gill filaments of two species of fish heavily infested with C. branchialis were examined with the transmission electron microscope. The flagellates are attached to the surface of the gill epithelium by their recurrent flagella. A prominent ridge on the flagellar membrane contacts the host cell membrane, forming a zone of gap junction and leaving a space of about 10 nm between the two membranes. The flagella do not penetrate into the epithelial cells. No other modifications of the cell membrane could be detected and the host cell reveals no signs of damage. Assumptions on the pathogenicity of C. branchialis are discussed in view of ultrastructural findings, which suggest that this flagellate is non-pathogenic and ectocommensal.  相似文献   

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