The potential of flat-bed passive integrated transponder antennae for studying habitat use by stream fishes

Abstract – Describing habitat use by stream fishes is important from both basic ecological and fisheries management points of view. The most widely used methods of measuring habitat use vary in degree of effort required, level of intrusiveness and in the level of spatial and temporal resolution. In this paper, we describe a remote monitoring technique that can provide detailed and continuous data on habitat use of individual fish in the field. The technique is based on the passive integrated transponder (PIT) system, in which a newly developed flat-bed antenna is placed on the stream bottom and simply requires a PIT-tagged fish to swim over it. We present data obtained from work using this new technology on brown trout ( Salmo trutta ) in stream enclosures, in which we describe habitat use and temporal patterns of movement by individuals and relate such data to growth rate and sex of the individual fish as well as to pool depth and time of day. In addition, we describe the range of applications of the flat-bed PIT-antenna as well as the advantages and disadvantages of using the system. ^NOTE     

Tagging: on the use of passive integrated transponder (PIT) tags for the identification of fish

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.     

Evaluation of passive integrated transponder tags for marking the bullhead (Cottus gobio), a small benthic freshwater fish: effects on survival, growth and swimming capacity

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.     

Fish–habitat relationships and fish conservation in small coastal streams in southern Spain

• 1. Studies dealing with the fish fauna of coastal streams are scarce in the scientific literature, particularly those from Mediterranean climates. Owing to their small size, these systems suffer extreme seasonal fluctuations, following the typical Mediterranean flood–drought cycle and leading to a high risk of extinction to freshwater fish.
• 2. This work analyses fish distribution in 14 stream stretches belonging to eight basins in the northern sector of the Strait of Gibraltar (southern Spain). Fish–habitat relationships were studied through multivariate ordination techniques at two scales: basin and stretch.
• 3. A principal components analysis clearly discriminated larger and more sinuous basins from smaller and steeper ones. This ordination was related to the non‐migratory freshwater fish species richness and to the total number of fish species present in the middle reaches of each basin.
• 4. The main sources of variation in community composition and habitat characteristics in the different stretches were related to a clear upstream–downstream gradient, along which total species richness increased.
• 5. These small coastal basins are inhabited by two highly endangered species, Andalusian toothcarp (Aphanius baeticus) and Iberian chub (Squalius pyrenaicus), and have similar or higher overall freshwater species richness than larger adjacent basins. The near absences of flow regulation and introduced species make these streams one of the few types of Iberian aquatic system where unaltered fish–habitat relationships can be studied.

Copyright © 2005 John Wiley & Sons, Ltd.     

Concurrent assessment of fish and habitat in warmwater streams in Wyoming

Abstract  Fisheries research and management in North America have focused largely on sport fishes, but native non-game fishes have attracted increased attention due to their declines. The Warmwater Stream Assessment (WSA) was developed to evaluate simultaneously both fish and habitat in Wyoming streams by a process that includes three major components: (1) stream-reach selection and accumulation of existing information, (2) fish and habitat sampling and (3) summarisation and evaluation of fish and habitat information. Fish are sampled by electric fishing or seining and habitat is measured at reach and channel-unit (i.e. pool, run, riffle, side channel, or backwater) scales. Fish and habitat data are subsequently summarised using a data-matrix approach. Hierarchical decision trees are used to assess critical habitat requirements for each fish species expected or found in the reach. Combined measurements of available habitat and the ecology of individual species contribute to the evaluation of the observed fish assemblage. The WSA incorporates knowledge of the fish assemblage and habitat features to enable inferences of factors likely influencing both the fish assemblage and their habitat. The WSA was developed for warmwater streams in Wyoming, but its philosophy, process and conceptual basis may be applied to environmental assessments in other geographical areas.     

Evaluation of two anaesthetic agents and the passive integrated transponder tagging system in Octopus vulgaris (Cuvier 1797)

Octopus vulgaris is a species of demand in the market with the potential to diversify European aquaculture. However, this species develops complex social interactions under culture conditions, which may have negative effects on its growth, survival and profitability. In order to understand its behaviour under such conditions, individual tagging systems allow a careful evaluation of biological parameters, such as growth and longevity. The present work describes a combined protocol (anaesthetic and tagging) for implanting subcutaneous passive integrated transponder tags (PIT). The effect of two anaesthetic agents in facilitating octopus handling is assessed: clove oil at 20–40–100 mg L^?1 and ethanol (96%) at 1–1.5–2%. The most suitable body location of PIT tags, its effect on growth and mortality, the addition of a stitch and the PIT retention rate after 2 months in floating cages were evaluated. It was concluded that immersion in seawater with 1.5% of ethanol at 22.3±0.5 °C is a suitable anaesthetic for this species. The results showed that the best‐selected PIT body location was the upper left arm III. No effect of the PIT tagging system was found on growth and survival when tagged and untagged octopuses were compared. It was observed after 2 months that the stitch did not induce an increase in the retention rate and 81–100% tag retention regardless of the dietary treatment.     

基于视频理解的活体鱼水质监测实验

声学标签监测技术是声波监测技术的一种主动识别方法,其通过接收、处理移植或捆绑于鱼类身上的声学标签发射的声波信号来获得鱼类二维、三维运动轨迹,具有原位观察、定位准确、数据处理简单和数据连续性好等优点。文章介绍了声学标签监测技术的组成及工作原理,并根据异常数据的不同特点总结了一套完整的数据去噪、清洗的处理方法,该法可快速得到鱼类的二维、三维运动轨迹。通过实例分析了鱼类运动轨迹的分布情况以及变化规律。根据鱼类在不同水生态环境中的运动行为响应情况,可以直接或间接判断水中污染物或有毒物质对鱼类的潜在影响以及实际毒性,为渔业养殖水质环境评价、水质监测及预警、水生态健康评价以及水生态修复效果评价的研究提供参考依据。

     

Winter distribution and habitat use by fish in a regulated lowland river system of south-east England

The macrohabitat preferences of 1+ fish (10 cm FL) and the microhabitat use of 0+ juvenile fishes in the River Lee catchment (UK) were examined from data collected over a 3-year period between late autumn and early spring using depletion sampling and point abundance sampling, respectively. Canonical correspondence analysis and habitat profiles revealed preferences in the more rheophilous fish species (e.g. brown trout, Salmo trutta L . , barbel, Barbus barbus (L.)) for features characteristic of upstream natural channels and meander sections of the by-passed old river, with the more ubiquitous (e.g. perch, Perca fluviatilis L.) and limnophilous fishes [e.g. pike, Esox lucius L . , tench, Tinca tinca (L.)] preferring habitats mainly in downstream channelised stretches. The microhabitat of 0+ juvenile fishes in the River Lee was similar to that reported elsewhere for the same species, influenced mainly by channel width, depth, and distance from the bank, though microhabitat overlap in 0+ roach, Rutilus rutilus (L.), and gudgeon, Gobio gobio (L.), was greater in the Lee than observed in larger, more open river systems.     

A comparison of swimming capacity and energy use in seven European freshwater fish species

Abstract –  Migrating fish species with different swimming capacities and energy use show different capacities for passing obstacles between habitats, such as culverts and fish ladders. Here, we present an integrated study on swimming capacity and energetic use in seven European freshwater fish species with different ranges of migration (brown trout Salmo trutta L., European perch Perca fluviatilis L., roach Rutilus rutilus L., common carp Cyprinus carpio L., gudgeon Gobio gobio L., bullhead Cottus gobio L. and stone loach Barbatula barbatula L.). Critical ( U _crit), optimal ( U _opt) and maximum ( U _max) swimming speed and oxygen consumption ( M O₂) were analysed and showed values correlated to migration capacity with highest swimming capacities in trout and roach and lowest in stone loach and bullhead. The resulting data can be used to make estimates of maximum passable water speeds in culverts. In conclusion, long-distance migrators show higher swimming capacities and can potentially clear obstacles easier than short distance migrators with lower swimming capacities. Even small obstacles (<25 cm) could be a barrier for genetic exchange between populations in short-distance migrators.     

Spatial patterning of habitat for Oncorhynchus mykiss in a system of intermittent and perennial streams

Abstract –  The salmonid Oncorhynchus mykiss tends to inhabit forested or snow-fed streams having cold reliable flows, but in the California chaparral they inhabit rain-fed stream networks with extensive areas of intermittent flow. We hypothesised that hydrological mechanisms in such watersheds tend to spatially segregate spawning and over-summering habitats, and tested the hypothesis using observations from a series of tributaries in a pristine watershed. Consistent with the hypothesis, reaches with suitably sized spawning gravels tended to occur in intermittent tributaries, and also the perennial mainstem (which was too warm for over-summering). In early summer, juvenile O. mykiss (<10 cm) occurred at similar densities in the intermittent and perennial tributaries, but larger fish had greater densities in perennial tributaries. Large wood debris would be expected to mitigate the spatial segregation of habitats somewhat, but was scarce, though stream-side outcrops appeared to partially compensate by forcing gravel bars in high-gradient channels.     

一种基于多点数据采集的水产养殖监控系统

为了实现对水产养殖池塘内水质参数的多点采集及实时监控,本文利用数字化数据采集技术、嵌入式系统技术以及无线传感器网络技术等,开发了一种水产养殖监控系统。此系统不仅可以利用基站采集到定点的水质参数,还能够利用机器鱼搭载无线传感器的方式采集到池塘内不定点的水质参数,实现了多点数据采集,并通过基站上的人机交互模块以及中心机房的上位机与用户进行交互。结果表明,该系统运行稳定,采集的数据符合所需的精度要求,监控范围大大提高,能够满足水产养殖监控的需要。     

The status of host fish populations and fish species richness in European freshwater pearl mussel (Margaritifera margaritifera) streams

• 1. The status of host fish populations and fish species richness was investigated at 36 sites of 20 extant freshwater pearl mussel populations, including the drainages of the Elbe, Danube, Rhine, Weser, Aulne, Kemijoki and Tuuloma in Germany, the Czech Republic, France and Finland, by carrying out comparative electrofishings.
• 2. Brown trout (Salmo trutta f. fario) were found to be the available host fish for pearl mussels in all except one of the streams investigated with mean densities of 2861 ha^?1 (range 0–8710 ha^?1) and a mean biomass of 119 kg ha^?1 (range 0–478 kg ha^?1). Streams that had been frequently stocked with brown trout had higher trout biomass and densities of host fish than natural populations, but trout stocking had no positive effect in two of the streams investigated.
• 3. Fish species richness ranged from 2 to 16 species per stream and showed a negative correlation with host fish biomass and host fish densities. Undisturbed oligotrophic pearl mussel headwater streams usually only yielded a low number of fish species. Habitat degradation can reduce competitiveness of specialized trout and result in an increased abundance of ubiquitous or atypical species.
• 4. A link between the lack of juvenile pearl mussels and a lack of suitable host fish was only rarely observed. Functional pearl mussel populations with relatively high numbers of juveniles had significantly lower densities and biomass of host fish than pearl mussel populations without recent recruitment.
• 5. This study suggests that 0+ host fish are not necessarily required to sustain functional pearl mussel populations. Low densities of host fish can be compensated by the higher glochidia carrying capacity of older host fish with limited previous contact with pearl mussel glochidia, by the long reproductive period of mussels, and by low mortality rates of juvenile mussels during their post‐parasitic phase.

Copyright © 2005 John Wiley & Sons, Ltd.     

A computerized environmental monitoring and control system for use in aquaculture

A computerized environmental monitoring and control system (CEMACS) has been controlling environmental parameters in finfish broodstock maturation systems for three years, including successful maturation regimes for gag grouper (Mycteroperca microlepis), red drum (Sciaenops ocellatus), and common snook (Centropomus undecimalis). The system monitors and controls photoperiod and temperature, and provides a continuous record of these parameters in digital form. It also monitors critical support equipment and notifies key personnel by telephone in event of equipment failure. Data may be analyzed using the system's computing capabilities or transferred to a more powerful computer for more sophisticated analysis. Similar systems could have wide application in commercial aquaculture, especially in intensive systems where equipment failure can be disastrous in only a matter of minutes.     

Biology and habitat use of three-spined stickleback (Gasterosteus aculeatus) in intermittent Mediterranean streams

Abstract –  We present the first data on three-spined stickleback ( Gasterosteus aculeatus ) life history and habitat use in seasonal Mediterranean streams, analysing populations from NE Iberian Peninsula. Stickleback populations were strictly annual, with reproduction events involving exclusively 1+ fish. Somatic growth was concentrated in two periods, one in spring and early summer, and another in autumn and winter. During summer there was a clear stop in the somatic growth, coupled with low values of somatic condition. This growth pattern contrasts both with that of other Mediterranean stream fish species and that of stickleback in other European locations. Stickleback populations occupied mainly intermediate locations along fluvial gradients. The presence of abundant aquatic vegetation was identified as one of the main factors related with both stickleback presence and the abundance of its populations, while the latter was also negatively related with that of invasive fish and crayfish species. Stickleback tended to occur in native-dominated fish communities, being almost absent from lower stream reaches, which bear high abundances of invasive fish species.     

深水网箱多波束水声鱼群状态监测仪的改进设计

针对离岸深水网箱养殖的鱼群安全问题,采用多波束水声技术监测鱼群状态的方法.结合信号处理技术、通用分组无线业务(GPRS)无线传输技术及串口通信技术,开发了一套多波束水声鱼群状态监测仪.监测仪完成1次网箱扫描只需5s;实现了监测数据的即采即发功能,提高了系统的实时性;改进了电路结构,降低了系统复杂度,减小了系统体积,降低...     

Effects of predation and intraspecific interactions on habitat use and foraging by brown trout in artificial streams

Abstract— We studied habitat use, foraging rates and behavior of 10 cm and 12 cm long brown trout, Salmo trutta , at two densities, 1.5 and 3.0 fish. m⁻², in artificial streams that contained either the amphipod, Gammarus pulex , alone or G. pulex together with the piscivore, northern pike, Esox lucius. Gammarus were stocked in and largely restricted to the pools at a density of 128 Gammurus. m⁻² . pool⁻¹ Large trout (12 cm) used pools more and riffles less when small trout (10 cm) were present than when small trout were absent. Small trout consumed fewer Gammarus when together with large trout than when alone, but showed no difference in habitat use in the presence and abscnce of large trout. Habitat use and number of Gammarus consumed per trout were not affected by trout density for either size-class when alone. For both size-classes of trout, use of pools and foraging rates were higher in the absence than in the presence of pike, and pike primarily resided in the pools. The number of aggressive interactions by both size-classes of trout decreased when pike was present. Our results indicate that for habitats that differ in food resources and predation risk, size structure may affect habitat use and foraging by brown trout.     

鱼塘溶解氧无线监测与控制系统研究

溶解氧检测在水产养殖中起着至关重要的作用。研制了一套通过无线以太网(WIFI)连接,LabVIEW程序控制,并通过GSM网络使用户远程监控池塘溶解氧的溶解氧无线监测与控制系统。该系统能够在线检测溶解氧、温度等主要环境参数,并根据环境情况实施对增氧机的控制,业主可远程电脑监控或者通过手机远程监测鱼塘水质状况,并发送增氧命令,进行远程手动启停增氧机。在溶解氧超标时,系统可以自动启停增氧机,并向用户发送报告。试验结果表明,该方案提高了水质监控系统的控制性能,且具有应用前景。     

不同施肥方法对鱼蚌综合养殖水体水化学的影响

通过155 d的围隔实验检验了不同施肥方法对鱼蚌综合养殖水体水化学的影响.鱼蚌放养种类为三角帆蚌、草鱼、鲫、鲢和鳙,鱼蚌比例为1.5∶1.施肥处理为施鸭粪(DM)、施化肥(CF)及结合施鸭粪和化肥(DC).实验期间定期采样分析水化学指标.各施肥处理间透明度(SD)、溶氧(DO)、硫酸根离子、氯离子、碳酸根离子、重碳酸根离子、钙离子(Ca2+)、镁离子(Mg2+)、总碱度、总硬度、氨态氮(TAN)、硝酸态氮(NO3-N)、亚硝酸态氮(NO2-N)、活性磷(PO4-p)、总氮(TN)、总磷(TP)和高锰酸钾指数(CODMn)均无显著差异,但围隔CF内PO4-P/TP显著高于围隔DM,5月20日-7月18日围隔CF内pH显著低于围隔DM.随养殖时间延长,各处理围隔内SD、DO、Ca2+和Ca2 +/Mg2+呈下降趋势,但TAN、NO2-N、TN、TP和CODMn呈上升趋势.结果表明,在投喂配合饲料的基础上少量施鸭粪、化肥或结合施鸭粪和化肥不会导致鱼蚌综合养殖水体主要离子、总碱度、总硬度、TAN、NO3-N、NO2-N、PO4-P、TN、TP和CODMn含量产生显著差异.相比之下,施化肥的水体CODMn较低,PO4-P/TP较高;施鸭粪的水体CODMn较高,PO4-P/TP较低;结合施鸭粪和化肥的水体CODMn和PO4-P/TP介于施化肥和施鸭粪的水体之间.鉴于结合施鸭粪和化肥的水体珍珠产量高于单独施鸭粪或施化肥的水体,可认为该施肥措施有利于三角帆蚌生长及其珍珠囊内的珍珠质分泌.