Microflora Associated with the Digestive-Transport Surfaces of Fish and Their Parasitic Cestodes

The symbiotic microflora is described that is associated to various degrees with the digestive-transport surfaces of pike and burbot and their parasitic cestodes T. nodulosus and E. rugosum, respectively, as well as of L. intestinalis plerocercoids from the body cavity of bream. Some of these bacteria possess amylolytic and proteolytic activity, which indicates their participation in both the digestion of the host and of the parasite.     

On Differentiation of Water Bodies with Respect to 90Sr Accumulation by Fish

Russian Journal of Ecology -     

Changes in phototactic behavior of Daphnia magna clone C1 242 in response to copper, cadmium and pentachlorophenol

In order to develop a sound biotechnique for monitoring water quality that builds on the previous experiments carried out in our laboratory, a specific D. magna clone C1242 was used to study the effects of pollutants on phototactic behavior, in all experiments, the animals showed a stable and repeatable phototactic index approximated 0.2 in the presence and 0.4 in the absence of fish kairomenes, which decreased significantly in response to pollutants. There existed no pollutant x fish kairomone interaction, indicating the changes in phototactic behavior of animals imposed by pollutants were independent of the presence of fish kairomones. The detection limits for changes in phototactic behavior of D. magna clone C1 242 are 0.04 mg/L for copper, 0.02 mg/L for cadmium, and 0.80 mg/L for PCP, respectively, quite lowerthan LC50(48 h). The changes in phototactic behavior in presence to pollutants occurred quickly(3 h) compared to the period over whole acute toxicity tests. Therefore, D. magna clone C1 242 could be potentially used to monitor water quality. Moreover, the phototactic behavior did not decrease further in the pollutant mixtures employed in our experiments compared to individual pollutants, except in the Cd-PCP Lre.atme~t.This fact suggests that the formation of water quality criteria must be based upon pollutant mixture tests.Keywords: Daphnia; phototactic behavior; copper; cadmium; pentachlorophenol; fish kairomenes     

The Problems of Fishermen in the Southern Aral Sea Region

The main objective of this paper is the presentation of water scarcity and water quality problems of fishery and fishermen in the southern Aral Sea region Kazakhstan. We tried in the past to inform interested people about our suggestions how to rehabilitate the situation, how to produce relatively enough fish for the functioning of local fish processing industry and to give people jobs, but we were unable so far to convince decision makers about innovations needed. It is essential therefore to reiterate some of the well-known problems of the region, called the Aral Sea crisis, but we concentrate mostly on the problems for the fishermen. While we do this, we understand, however, that the problem requires solution within the concept of a socioeconomic sustainable development for which we suggest the development of a decision support system based upon a computer simulation model providing optimal solutions.     

广西金钟山自然保护区鱼类资源考察报告

2004年11月14日至12月17日，在广西金钟山自然保护区内水域中共获淡水鱼类样品110余号，结合以往的调查资料。初步确定保护区淡水鱼类共有52种，分别隶属于4目13科1．45属．通过对保护区鱼类资源的实地考察，从生态区系的角度叙述了保护区野生鱼类资源的区系概况和分布特点，并对保护区鱼类资源的管理和合理利用提出了建议。     

鲁西北地区渍涝洼地人工鱼塘─台田的环境分析

鲁西北地区是黄淮海平原中低产田渍涝洼地的主要分布区之一。在鲁西北的禹城市，利用挖鱼塘、建台田的工程措施，综合改造利用这类洼地。工程实施后，通过水盐调控，改善了洼地的环境状况。监测结果表明：洼地台田土壤含盐量降低，土壤逐渐熟化。土壤有机质大量整治前后分别为０．５８２％（１９８６年）、０．９８９％（１９８９年）．土壤中的全氮、全磷也由整冶前的０．０２％、０．１４％上升到整治后的０．０６１％和０．１５８％。土壤盐分含量逐年降低，由０．５０～０．９２％下降到０．０６～Ｏ２９％。挖鱼塘建台田的生态工程措施，使浅层地下水地表化，解决了洼地积水蒸发等形成的盐渍化问题。综合环境效应显示，洼地原有的自然状况向良性转化，达到了初步治理的目的。     

Toxic effects of orimulsion on rainbow trout <Emphasis Type="Italic">oncorhynchus mykiss</Emphasis>

GOAL, SCOPE AND BACKGROUND: Orimulsion (stable emulsion of natural bitumen and water) is a new imported industrial fuel in Lithuania. No data on its toxicity to fish is freely available. The aim of this study was to investigate sensitivity of rainbow trout (Oncorhynchus mykiss) to acute and chronic toxicity of orimulsion and to estimate the Maximum Acceptable Toxicant Concentration (MATC) of orimulsion to fish. METHODS: Laboratory tests were conducted on rainbow trout in all stages of development (embryos, larvae, adults). Acute toxicity (96-hour duration) and long-term (28 or 60-day duration) tests evaluating the wide range spectrum of biological indices were performed under semi-static conditions. RESULTS AND DISCUSSION: Median lethal concentration (96-hour LC50) values and their 95% confidence intervals derived from the tests were: 0.1 (0.09-0.12) to embryos, 0.06 (0.05-0.07) to larvae and 2.22 (2.02-2.43) to adult fish, and 28-day LC50 to adult fish was found to be 0.26 (0.21-0.32) g/l of total orimulsion respectively. The acute toxicity of orimulsion to rainbow trout can be characterised by a narrow zone of toxic effect and a sharp boundary between lethal and sublethal concentrations. The lowest 'safe' or 'no-effect' concentration values of total orimulsion obtained in long-term tests were equal to 0.09 g/l to adult fish, 0.019 g/l to embryos, and 0.0017 g/l to larvae. Proposed value of 'application factor' for orimulsion was found to be equal to 0.03. Since orimulsion has the property to disperse in all water volume, its toxic effect on fish can be characterised by the combined effects of dispersion and water-soluble-fraction. CONCLUSIONS: Maximum Acceptable Toxicant Concentration (MATC) of 0.0017 g/l of total orimulsion to fish was derived from long-term tests based on the most sensitive parameter of rainbow trout larvae (relative mass increase at the end of the test). According to substance toxicity classification accepted for Lithuanian inland waters, orimulsion can be referred to substances of 'moderate' toxicity to fish. RECOMMENDATIONS AND OUTLOOK: For prediction and evaluation of toxic impact of orimulsion accident spills on fish, some recommendations should be given. Since orimulsion has the property to disperse in all water volume during short time periods, the amounts of both spilled orimulsion and polluted water should be ascertained. Once both parameters are known, the real concentration of orimulsion in the water body must be determined. Then this concentration must be compared with 'safe' concentration to fish. By use of 'application factor' 0.03, approximate MATC for other fish species can be estimated when only acute toxicity data (96-hour LC50 value) is available.     

Induced alkoxyresorufin-O-dealkylases in tilapias (Oreochromis niloticus) from Guandu river, Rio de Janeiro, Brazil

The activity of fish monooxygenases has been extensively used as a monitoring tool to detect contamination of water bodies by cytochrome P450-inducing agents. In this study we evaluated the activities of ethoxy- (EROD), methoxy- (MROD) and pentoxy- (PROD) resorufin-O-dealkylases in the liver of Nile tilapias (Oreochromis niloticus) collected at the Guandu river, at a reference clean site (Lake 1) and at two other sampling sites (Lakes 2 and 3) in Rio de Janeiro state, Brazil. Alkoxyresorufin-O-dealkylases were measured fluorimetrically in the hepatic S9 fraction. EROD (17.7-fold), MROD (14.2-fold) as well as PROD activities were considerably higher in tilapias from Guandu river. A moderate increase of EROD (5.0-fold) and MROD (5.4-fold) was also found in tilapias from Lake 3. These findings suggest that Guandu river watershed, the main source of urban drinking water supply in Rio de Janeiro, is polluted with CYP1A-inducing xenobiotics. Furthermore, we also found a good linear relationship between EROD and MROD, a finding that agrees with the hypothesis that the two reactions are catalysed by the same CYP1A isoform in O. niloticus.     

Trace metal levels in freshwater fish, sediment and water

The trace metal concentrations in water, sediment and aquatic organisms, such as fish, could indicate the level and tendency of the pollution. This is important not only for the protection of the environment, but for evaluation of the quality of fish meat either captured from natural waters or cultured in fishponds. The total trace metal concentrations in samples of fish from different regions of Hungary and from different species have been determined by using an X-ray fluorescence technique (EDXRF). Water, sediment and fish samples from fishpond systems with different feeding and stocking has also been analyzed. In the case of zinc contents, differences have been traced between the cultured and wild common carp. In the case of common carp reared under different feeding conditions, differences were also observed in the zinc concentration. The retention of the trace metals in the fish has been studied by measuring the levels in sediment, water and feed. The different retention can be explained by the different availability of zinc in the applied feeds, which can be related to the presence of different metal species in the feeds.