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1.
The Atlantic halibut (Hippoglossus hippoglossus L.) is a new species in Norwegian aquaculture. However, in ongrowing trials, halibut shows variable and generally poor rates of growth. The halibut is a flatfish that spends most of its time resting on the bottom, and it was hypothesized that high stocking densities with frequent social interactions could lead to behaviour changes, reduced appetite and impaired welfare. Halibut were kept in six tanks at low, medium, and high densities (18%, 54% and 112% bottom coverage). All fish were individually tagged with Trovan™ passive implant transponder (PIT) tags, allowing an antenna to register fish swimming at the surface. Swimming and feeding behaviour was also recorded by underwater video cameras. Individual growth rates were highly variable, but food consumption and growth rates fell significantly with increasing stocking density, while individual swimming activity rose with increasing density. Frequent “surface swimmers” had a significantly lower growth rate than fish that were seldom recorded by the PIT antennae. Surface swimming may therefore be an indicator of suboptimal growth rates and impaired welfare in reared halibut.  相似文献   

2.
Abstract –  This study examined potential adverse effects of surgically implanted passive integrated transponder (PIT) tags (12 × 2.1 mm) on bullhead ( Cottus gobio L.) of three different length-classes (I: 50–64 mm, II: 65–79 mm, III: 80–94 mm). During a 7-week laboratory experiment, the rate of PIT tag loss, incision closure time, survival, growth and swimming capacity were tested. The PIT tag weight to fish body weight ratio varied between 1.04% and 4.85%. The mean incision closure time differed significantly among length-classes and varied between 2.8 (I) and 4.3 (III) weeks. Nevertheless, PIT tag retention did not differ among length-classes and was ≥90%. The survival of untagged, sham-tagged and PIT-tagged bullheads was ≥90% and did not differ within or among length-classes. Finally, within each length-class, there was no difference in growth and swimming capacity among treatments. Hence, these results suggest the applicability of PIT tags for individually tagging bullheads ≥50 mm.  相似文献   

3.
5种鱼类标志对草鱼临界游泳速度的影响   总被引:1,自引:0,他引:1       下载免费PDF全文
采用被动整合雷达标志法(PIT)、切鳍标记、荧光标记、超声波标志和T型标志这5种标志方法对草鱼(Ctenopharyngodon idellus)进行标记后,测定其临界游泳速度,研究5种不同标记对草鱼游泳能力的影响。将试验草鱼按不同体长分为3组:15~18 cm,18~21 cm,21~25 cm,每个体长组均设置对照组,并分别进行以上5种鱼类标志,测量标志后草鱼的绝对临界游泳速度和相对临界游泳速度。采用SPSS17.0统计软件进行数据的分析比较。研究结果表明,随着体长增加,草鱼的绝对临界游泳速度增大,相对临界游泳速度减小;超声波标志对3个体长组草鱼的临界游泳速度均有极显著影响(P0.01),标志后草鱼绝对临界游泳速度分别下降18.72%、16.40%、23.15%,相对临界游泳速度分别下降18.95%、17.78%、21.86%;T型标志对15~18 cm体长组草鱼的临界游泳速度有极显著性影响(P0.01),标志后草鱼绝对临界游泳速度下降8.35%,相对临界游泳速度下降9.30%,对体长大于18 cm的草鱼无显著性影响;PIT标志、切鳍标记和荧光标记对这3个体长组草鱼的临界游泳速度均无显著性影响(P0.05)。  相似文献   

4.
In the spring of 1996 and 1997, a prototype 400 kHz flat-plate (pass-by) passive integrated transponder tag interrogation (PIT tag) system was installed at the terminus of the downstream migrant (DSM) channel of the Bonneville Dam First Powerhouse, located on the Columbia River. The system was designed to interrogate previously PIT tagged juvenile salmonids migrating down the Columbia River without interfering with the traditional subsampling of fish passing through the facility. In addition, the design enables fish of virtually any size, and debris, to pass over the system's antennas without the port restrictions imposed by traditional pass-through PIT tag interrogation systems. We describe the fish facility in addition to the flat-plate system and its operation. The system tag reading efficiency was evaluated during 1996 and 1997 using a direct method based on the release of known numbers of tagged test fish and an indirect statistical procedure based on tagged run-at-large fish. The results showed that PIT tag reading efficiency during both years using the direct method averaged 97%, while that using the statistical procedure averaged 99% for the dual multiplexed antenna array. During the 1996 and 1997 field seasons 4371 and 14 733 fish, respectively, were recorded. Daily system functionality was monitored using stick tests (i.e., the passing of PIT tagged sticks across the antenna array).  相似文献   

5.
The effects of four different tagging methods (PIT, anchor T‐tag, Carlin tag and dummy radio transmitter) on survival, behaviour and growth of Atlantic salmon smolts during their downstream migration were examined in semi‐natural circular channels during a natural migration period in spring. Survival of smolts was high and tagging wounds healed well in all tagging groups. Tag loss rates were generally low, being the highest (2.5%) in the dummy radio transmitter group. Total length and body mass of the tagged and untagged smolts did not differ at the end of the experiment. Migration activity of smolts generally showed similar patterns among the treatments. However, Carlin‐tagged smolts started their migration slightly later than the PIT‐tagged fish, and smolts tagged with Carlin tag or dummy radio transmitter showed less overall migration activity than fish with PIT tag.  相似文献   

6.
To determine the efficacy of passive integrated transponder (PIT) tags for marking rohu Labeo rohita (Ham.) in the selective breeding programme, a series of experiments has been carried out at the Central Institute of Freshwater Aquaculture (CIFA) under the Indo–Norwegian project of ‘Selective breeding of rohu’. Six groups of rohu fingerlings with weight ranging from 2 g to 20 g were tagged with PIT tags to determine a suitable size range for tagging. Fingerlings weighing 8–15 g were found to be quite suitable for tagging with a PIT tag. Recovery of the PIT tag depends upon the survival of tagged fish under field conditions. Rejection of the PIT tag by rohu was observed to be only 0.05%. Through effective management practice, the survival of tagged fish increased up to 95%, and thus tag loss was minimized.  相似文献   

7.
全双工射频识别系统(RFID)相较于半双工具有操作简便、数据传输方便等优势,国外广泛应用于鱼道过鱼效果评价。针对而国内相关研究较少的现状,以植有PIT标签的仿野生齐口裂腹鱼(Schizothorax prenanti)识别与否作为评判系统监测效率高低的依据,定量分析鱼体入射角度、鱼体入射范围、鱼体长大小和游泳速度对全双工射频识别系统监测效率的影响,以接收到监测数据作为因变量,构建Logistic回归模型,利用AIC模型准则筛选出最优的Logistic回归模型。结果表明,游泳速度(P=0.001)和鱼体长大小(P=0.03)与系统成功监测概率呈负相关。鱼体入射角度(0°~90°)对系统监测效率的影响不显著(P0.05);鱼体入射范围0~10 cm的监测效率显著高于入射20~30 cm和30~40 cm(P0.05)。为进一步提高鱼道监测效率,建议在开展实际鱼道工程监测前,应掌握鱼类基础参数(如体长)和行为(如游泳速度)数据,合理布置天线位置,将有助于为监测评估后的鱼道优化设计提供技术支撑和数据参考。  相似文献   

8.
The effect of two physical tagging systems, Visible Implant Elastomer (VIE) and Passive Integrated Transponder (PIT), was evaluated in red porgy (Pagrus pagrus) fingerlings, at different sizes. For VIE tagging, the weight classes were <1 and 1?C5?g and no tag effect was detected on fish growth. There was a significant difference in mortality between tagged and untagged <1?g fish, but not for the 1?C5?g fish. The tag loss rate was null for all sizes, however, tags showed fragmentation. This partial tag loss was evaluated and quantified. Seven VIE colours were compared and arranged from best to worst visibility: green, red, pink, orange, yellow, white and blue. For PIT tagging, 2?C6?g, 5?C10?g and 10?C20?g weight classes were analysed. There was no significant tag effect on fish growth, for any size, nor on mortality from 10?g. Tag loss rate ranged from 2.9 to 5.9%. These results demonstrate that, in red porgy, VIE is a successful tagging system from 2?g onwards whereas PIT system is successful from 10?g onwards. The combination of both systems allows traceability of fish from a very small size on, which is necessary for the implementation of genetic breeding programmes.  相似文献   

9.
A controlled experiment mimicking Atlantic salmon (Salmo salar) pre-smolt farming conditions showed that fish exposed to 150 and 175% super oxygenated water produced higher levels of carbon dioxide with the subsequent decrease in water pH compared to control fish exposed to 100% O2. At the 7th day of exposure the hyperoxic fish showed larger individual variation in swimming activity compared to the controls. The individual variance in activity, tail beat frequency and scattering in the tanks among super oxygenated fish decreased from the 7th to the 21st day of exposure. The behavioural effects of hyperoxia were seen in relation to altered feed consumption halfway through the experiment, lower body weight, and altered haematological variables at day 21 of exposure. Plasma chloride was reduced in the exposed fish and haemoglobin decreased with increasing oxygen saturations. Plasma cortisol was elevated only in the 150% oxygenated group at day 21, while no effect on osmolality was recorded. The alterations in physiology and behaviour from day 7 to day 21 may be explained in terms of acclimation to increased oxygen saturations. This study shows that behaviour may be used as an indication of impaired water quality that may influence animal welfare negatively and eventually prevent an efficient production.  相似文献   

10.
《Fisheries Research》2007,87(2-3):280-284
A laboratory study was conducted to assess the effect of PIT tagging on survival and growth of young-of-the-year brown trout (Salmo trutta) and evaluate PIT tag loss as a function of body size at tagging. Transponders (11.5 mm long and 2.1 mm in diameter) were injected into the peritoneal cavity of fish ranging from 41 to 70 mm fork length (FL) using hypodermic needles. A total of 145 tagged fish and 136 control fish of similar size were reared over 4 weeks. Logistic regressions show that survival rate reached 95% for fish ≥52 mm FL at tagging (with a tag retention rate >70%), and 99% for fish ≥57 mm FL (tag retention rate >80%). No significant effect of tagging on growth (fork length and weight) was detected at the end of the experiment. The specific growth rate varied markedly among PIT-tagged fish regardless of fork length, weight or tag-to-body-weight ratio at tagging. Results suggest that juvenile brown trout larger than 57 mm FL (tag-to-body weight ratio in water <3.4%) can be marked by injection of 11.5 mm PIT into the peritoneal cavity with negligible effects on survival and growth, but this leads to a relatively high tag rejection rate (up to 20%).  相似文献   

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