Special features of fish species composition and community structure in small rivers of the Udmurt Republic

The composition and species richness of ichthyofauna have been studied in 36 stretches of small rivers in the Udmurt Republic to estimate the dependence of species richness on the distance from the river source and the level and type of anthropogenic load. Some specific features of modification of the fish community structure under the influence of agriculture, urbanization, and industry (oil production) have been revealed. Basic trends in the change of dominant complexes of fish species with an increase in the distance from the river source are described for small rivers flowing in different natural and anthropogenic landscapes of the Udmurt Republic.     

Changes in the structure of ichthyofauna in water bodies of Kaluga oblast over the past few decades

The structure of the ichthyofauna in water bodies of Kaluga oblast has undergone significant rearrangements over the past 20 years. The abundance of some species has increased, while that of other species has decreased; spontaneous dispersal of some fishes is underway. Synchronous fluctuations of fish abundance (“waves of life”) take place simultaneously in the Western Dvina, Dnieper, and Volga basins. These processes differ in intensity depending on fish species and are conditioned by a number of factors, including changes in hydrological regimes of rivers, improvement of the ecological state of small rivers, and increased poaching pressure. The results of monitoring the ichthyofauna fauna of small rivers are used as an example to trace the routes of fish dispersal and discuss changes in the composition of fish communities.     

Cesium accumulation by fish following acute input to lakes: a comparison of experimental and Chernobyl-impacted systems

An uptake parameter u (L kg⁻¹ d⁻¹) and a loss rate parameter k (d⁻¹) were estimated for the patterns of accumulation and loss of ¹³³Cs by three fish species following an experimental ¹³³Cs addition into a pond in South Carolina, USA. These u and k parameters were compared to similar estimates for fish from other experimental ponds and from lakes that received ¹³⁷Cs deposition from Chernobyl. Estimates of u from ponds and lakes declined with increasing potassium concentrations in the water column. Although loss rates were greater in the experimental ponds, the times required to reach maximum Cs concentrations in fish were similar between ponds and lakes, because ponds and lakes had similar retentions of Cs in the water column. The maximum Cs concentrations in fish were largely determined by initial Cs concentrations in the water column. These maximum concentrations in fish and the times required to reach these maxima are potentially useful indicators for assessments of risks to humans from fish consumption.     

长江中游典型鱼塘植莲的环境与经济效益分析

长江中游湿地区域的池塘经过连续多年的化肥养鱼导致了大量的氮、磷沉积在鱼塘底泥中。分析了鱼塘植莲对养殖后沉积的氮、磷的重新利用及植莲的经济效益。实验于2004年在位于长江中游的武汉市涨渡湖渔场进行。根据收支平衡计算了实验池氮、磷的转移量,根据投入产出计算了实验池的经济收入。逐月分析了池塘中水质理化指标和底泥中总凯氏氮（TKN）和总磷（TP）的含量。方差分析表明：总凯氏氮、总磷在池塘底泥表层（0～5 cm）、中层（5～10 cm）和底层（10～50 cm）当中的含量都出现显著性降低(〖WTBX〗P〖WTBZ〗<005)。养鱼池塘通过植莲后,每公顷有1 50938±2211 kg氮和188995±282 kg磷被重新利用;鱼塘植莲产生的经济效益平均为每公顷52 031±1 579元。实验表明鱼塘植莲既能够有效地改善池塘养殖的生态条件,又能带来较高的经济收入,是长江流域湿地保护和综合利用的一种高效的农业生态模式。     

Species and Environmental Diversity of Fish of the Northern Dvina River Basin

The general characteristics of ichthyofauna from the Northern Dvina River are obtained. Based on the results of ichthyological surveys in 1984–2012, as well as bibliographical and archival data, the present composition of the fish community is presented with an accounting of introduced and self-colonized species. The taxonomic status of fish and their belonging to various faunal complexes is considered. In the ecological aspect, the belonging of fish to different ecological groups differing in the feeding and natural reproduction (spawning substrate, methods of spawning, and spawning periods) is distinguished.     

Cladocerans under conditions of small river damming by man and beavers

In beaver ponds, the species diversity, abundance, biomass, and production of cladocerans and the amount of food consumed by them have increased and the composition of dominant species has changed as compared to those in the stretches of small rivers with running water or dammed by man. The stimulating effect of water from a beaver pond has been confirmed in laboratory experiments. The average number of juvenile Ceriodaphnia affinis produced by one female was considerably greater in this water than in the water from flowing and dammed (by man) river stretches.     

淡水养殖水体溶解氧含量诊断分析及浮头泛塘气象预报

通过实时监测荆州农试站养殖塘各种水质要素,结合2011~2012年养殖塘发生的25个鱼泛塘实例,探讨了养殖水体溶解氧含量与气象要素之间的联系。分析表明:养殖水体溶解氧含量与6 h变温、总辐射量、气压值正相关,与水温、空气相对湿度值负相关。从平时的调查记录来看,鱼泛塘事件主要发生在5~10月间,湿度大、气温低、气压下降、日照强度弱等都会引起溶解氧含量低,严重的会诱发鱼泛塘。根据25个鱼泛塘实例,结合气象要素的特点,提出了急剧降温降压型、寡照型、高温高热型3种鱼泛塘发生条件的概念模型,分别以实例进行了验证,并初步总结出根据气象要素观测资料进行浮头泛塘预报的方法和流程     

不同养殖模式池塘沉降颗粒营养物质组成特征

2012年4~10月采用自制沉降颗粒收集装置收集主养草鱼和黄颡鱼池塘生态系统中沉降颗粒物,开展了颗粒物质的垂直沉降量以及沉降颗粒中碳氮磷等营养物质的组成及沉降通量的季节变化特征的研究。结果表明:养殖可以显著提高池塘颗粒物质的垂直沉降量,主养草鱼池塘中颗粒物质垂直沉降量显著高于主养黄颡鱼池塘(p0.01),且两种养殖模式池塘颗粒物质沉降量随着养殖时间推进有显著增加的趋势。主养草鱼的池塘中颗粒物质垂直沉降量在100.39~414.66g/(m2·d)之间变化,平均为224.46g/(m2·d),主养黄颡鱼池塘中沉降颗粒物质垂直沉降量在34.14~272.91g/(m2·d)之间变化,平均为155.18g/(m2·d)。两种养殖模式沉降颗粒的碳氮磷成分在养殖周期内的变化规律不明显但具有相似的变化趋势,主养黄颡鱼池塘沉降颗粒中TN、TC、TOC和TON的含量均比同时期主养草鱼高,且均随着养殖时间的推进,沉降颗粒中碳氮磷的总量呈增加趋势。两种养殖模式池塘沉降颗粒中的C/N比值与沉积物中的C/N比值较为接近,表明沉降颗粒与沉积物营养物质来源具有一定的相似性,同时养殖系统内养殖对象与其所处环境的相互依存和相互影响对颗粒物质的产生以及沉降具有重要作用。     

Trends of interpopulation variation in meristic characters of seismosensory canals on the head of roach, <Emphasis Type="Italic">Rutilus rutilus</Emphasis> (L.), in anthropogenically polluted environments

Patterns in the quantitative manifestation of meristic characters of seismosensory canals on the head of roach have been studied in fish from populations inhabiting ten river and pond water areas of the Udmurt Republic exposed to different kinds and levels of anthropogenic pollution. Trends of interpopulation variation in the average numbers of pores in some seismosensory canals have been revealed, and their statistical relationship with the level of pollution has been evaluated.     

Ecological Characteristics of Small Rodents Living in Collective Gardens

The small-rodent populations of five collective gardens have been studied. The example of one of the populations has been used to monitor the annual cycle of population size. The species composition and animal number depends on the biotope, climatic conditions, and the anthropogenic load. The ratios between species in the gardens and neighboring biotopes differ from each other, with different species being dominant. It is assumed that small mammals use garden plots as refugia.     

Inverse dependency of particle residence times in ponds to the concentration of phosphate, the limiting nutrient

234Th, a commonly used short-lived particle-reactive tracer in marine systems, was measured in three different holding pond series at the Rocky Flats Environmental Technology Site (RFETS), Colorado, along with its parent nuclide 238U, to determine steady-state residence times of particle-reactive actinides such as Pu, and of particles. Series B ponds, which received industrial effluent that includes ortho-phosphate (PO4) and actinides, differed from series A and C ponds, which did not. This difference was also evident in the calculated particle residence times, which were <1 day for the ponds B4 and B5, where PO4 concentrations were higher (1.4 and 1.8 mg/l), and 3 and 3.4 days for ponds A3 and C2, respectively, where ortho-phosphate concentrations were lower (<0.1 mg/l). Particle residence times thus showed an inverse relationship with the concentration of ortho-phosphate, the limiting nutrient in fresh water systems. The same relationship to the concentration of ortho-phosphate or any of the other nutrient elements was not evident for the residence times of dissolved 234Th, which ranged between 0.1 and 2 days. This can be attributed to higher concentrations of dissolved and particulate ligands with greater binding potential for actinides such as four-valent Th and Pu in ponds with higher ortho-phosphate concentrations. Regardless of actual ortho-phosphate concentration, however, at water residence (holding) times of 1 month in these ponds, particles and associated actinides would be expected to be completely removed from the pond water to sediments.     

New Fish Species in Water Bodies of Northeastern European Russia

Russian Journal of Ecology - Changes in the composition of ichthyofauna of northeastern European Russia under the effect of biological invasions are analyzed. It is shown that alien invader fish...     

Activity of Beavers as an Ecological Factor Affecting the Zooplankton of Small Rivers

The role of beavers in the transformation of small rivers is elucidated by analyzing the taxonomic and trophic structure of zooplankton in ponds differing in age, water flow rate, and the degree of overgrowing with higher aquatic plants. The building activity of beavers in the river system promotes the formation of biotopes of the ecotone type, in which the planktonic invertebrate community develops some features similar to or different from those of zooplanktonic communities from lakes and rivers undergoing anthropogenic eutrophication. The main distinctive feature of response to this activity in zooplankton is that its development reaches a plateau at the early and middle stages of succession, compared to that under conditions of anthropogenic eutrophication. For small rivers, the concept of zoogenic eutrophication (in addition to anthropogenic) is proposed.     

Microorganisms: Indicators of pollution in integrated livestock-fish farming systems

Twelve fishponds each measuring 1,000 m² stocked with 2,000 fish consisting of 85% Oreochromis niloticus, 14% Cyprinus carpio and 1% Ophicephalus striatus were used to determine the level of fecal coliforms in the pondwater and fish flesh and the presence of Salmonella in the pondwater. Water samples for coliforms were collected at weekly intervals while those for Salmonella were done biweekly from three pond sites. Fish were randomly sampled by seining the pond over a three-month period. Both water and fish samples were analyzed for coliforms with the multiple-tube fermentation technique and for Salmonella using the swab technique. Results showed coliform counts with mean concentrations varying from 29,700/L of water in the middle of the pond to 18,100/L farthest from the manure dumping site. Differences in concentration between collection sites were not significant (P > 0.05) but mean values obtained weekly differed significantly (P < 0.05). Tilapia had coliform counts of 1.7 while carp had 1.1/g flesh. Differences among fish samples of the same species were not significant (P > 0.05) but were significant between species (P < 0.05). Biochemical tests revealed the presence of E. coli and Klebsiella sp. and more commonly S. cholerasuis.     

The role of spring and rain floods in the development of zooplankton in beaver ponds

The role of spring floods as a factor determining the seasonal succession of zooplankton in beaver ponds is demonstrated. The absence of spring floods has an adverse effect on the zooplankton communities of beaver ponds. The taxonomic and trophic organization of communities becomes similar to that in areas exposed to anthropogenic imact. The rain floods in summer and autumn can return the system to early stages of seasonal succession.     

Heavy metals in four fish species from the French coast of the Eastern English Channel and Southern Bight of the North Sea

Shallow coastal waters act as nurseries for various fish species and have been recognized as essential fish habitat. We studied heavy metal concentrations in four fish species (plaice, dab, flounder and cod) as an indicator of large-scale habitat quality. The study took place along the French coasts between the Eastern English Channel and the Southern Bight of the North Sea. All species show different concentrations of measured metals (e.g., Cd, Cu, Mn and Pb) in liver but not in muscle. The highest concentrations are found for the flounder and the lowest for cod which is consistent with their habitat and diet. Although our results do not highlight levels of appreciable pollution within the study area, inter-site differences are mainly observed in the muscle tissues and are generally in agreement with the known environmental data (e.g., anthropogenic pressure). However, in the Bay of Seine, one of the most contaminated estuaries in Europe, metal concentrations are in the same range or even lower than those found in fish collected from areas distant from any anthropogenic pressures. At one site, the comparisons of the Cd, Cu and Pb concentrations between healthy and diseased dabs have been carried out on the muscle and liver tissues. The results of this preliminary study show a relationship between metal concentrations and the pathological status of the fish. The use of fish health as indicator of habitat quality is discussed.     

Species composition and quantitative representation of fishes in biotopes with the riffle minnow <Emphasis Type="Italic">Alburnoides bipunctatus</Emphasis>

Species composition of fishes was studied in rivers (capture sites) inhabited by the riffle minnow. In some localities, this species proved to occupy a leading position in the ichthyofauna, being obviously dominant. In small rivers, 16 species were caught together with it, including seven species regularly occurring in catches. The relative abundance of riffle minnow showed a moderate positive correlation with that of the gudgeon (0.568) and a nonsignificant negative correlation (?0.399) with that of the bleak. It is probable that the population dynamics of riffle minnow are determined mainly by natural intraspecific mechanisms rather than by water quality, which has changed only slightly in the rivers studied.     

Exposure of biota in the cooling pond of Ignalina NPP: hydrophytes

The radiological assessment of non-human biota is now accepted by a number of international bodies. In this connection the scientific basis to assess and evaluate biota internal and external radiation exposure is required. This paper presents the comparison of freshwater biota (hydrophyte species) exposure due to discharged anthropogenic radionuclides with that due to natural background radiation. The radionuclides from Ignalina Nuclear Power Plant (Lithuania) are discharged into cooling pond - Druksiai Lake. Submerged hydrophytes were selected as biota exposure indicators because they represent the largest biomass in this lake and have comparatively high radionuclide activity concentrations. The detailed methodology evaluation of the submerged hydrophyte dose rate is presented. The ionizing radiation exposure dose rates to submerged hydrophyte roots and above sediment parts due to the major radionuclides ((54)Mn, (60)Co, (137)Cs, (90)Sr) discharged into the INPP cooling pond - Druksiai Lake were 0.044 microGyh(-1) and 0.004 microGyh(-1), respectively. The internal exposure dose rate due to natural background alpha-emitters ((210)Po,(238)U, (226)Ra) was estimated to be 1.24 microGyh(-1), as compared with that of anthropogenic alpha-emitter (240)Pu - 0.04 microGyh(-1), whereas the external exposure was 0.069 microGyh(-1). The presented data deeper the knowledge about the concentration of radionuclides and submerged hydrophytes' exposure dose rates in European freshwater ecosystems.     

Histomorphological structure of the liver in roach (Rutilus rutilus) and pike (Esox lucius) from lakes with different levels of anthropogenic impact

Using histological techniques, changes in histomorphological characteristics of the liver were revealed in two fish species from lakes with different levels of anthropogenic impact. The most significant changes in the liver of roach from Kostomukshskoe Lake (used as a tailing dump of the Kostomuksha Mining and Ore-processing Plant) included initial stages of parenchymal protein dystrophy and, to a lesser extent, fatty dystrophy; in pike, fatty liver dystrophy prevailed. Compared to roach, pike proved to be more sensitive to ecological conditions in Kostomukshskoe lake, including increased water mineralization. In both fish species from Koivas Lake (20 km from the pollution source), only the initial stages of local dystrophic changes could be detected. The fish from clean Kamennoe Lake (located in a protected area) had no pathological changes in the liver.