Effects of Contaminants on Toxicity of the Lampricides TFM and Bayer 73 to Three Species of Fish

Waters in the Great Lakes basin contain more than 400 contaminant chemicals that potentially affect fishery resources, commerce, and human inhabitants. We determined in the laboratory the effects of selected contaminants on the toxicity of the widely used lampricides TFM (3-trifluoromethyl-4-nitrophenol) and Bayer 73 (2′,5-dichloro-4′-nitrosalicylanilide) to three species of fish—rainbow trout (Salmo gairdneri), white sucker (Catostomus commersoni), and fathead minnow (Pimephales promelas). The fish were exposed to paired mixtures of lampricides and selected contaminants in standardized, acute static toxicity tests to determine the resulting type of response—less than additive, additive, or greater than additive (synergistic). As expected, the toxicities of combinations of lampricides with organic pesticides, metal, industrial or municipal pollutants, and tannic acid were mostly additive. However, the toxicity of a combination of TFM, Delnav, and malathion was synergistic, and extremely small quantities of each chemical became lethal when mixed. The concentration that produced 50% mortality was 1.64 mg/L for TFM alone but only 0.041 mg/L for TFM with the pesticides. Toxicities of the pesticides in the combination also increased commensurately. The triple combination of chemicals produced extraordinary synergism and effectively demonstrated the hazards that may result if certain chemical combinations occur in the aquatic environment. However, synergism is not the only kind of toxic action that produces hazards to aquatic organisms. All three types of toxic action are of concern because toxic units produced by contaminant chemicals add to the toxic units of applied management chemicals. Since the toxicity of the majority of chemical combinations is simply additive, this cumulative toxic action contributes more total units to aquatic environments than the extreme actions of less than additive and synergism. The toxicity of the lampricide TFM, as well as other management chemicals, is reinforced by the presence of any contaminant that contributes additional units of toxicity. Therefore, all types of cumulative toxic action should be of concern to people and agencies involved with protecting the environment.     

Diel Vertical Migration of Round Goby Larvae in the Great Lakes

One hypothesis for the transcontinental and intra-Great Lakes basin transfer of round gobies (Neogobius melanostomus) has been that round gobies were pumped into the ballast water of ships. During June 2005 in Lake Erie, we obtained evidence of a vertical migration of round goby larvae, when we collected 167 round goby larvae in surface ichthyoplankton net tows at night and zero during day. These results complemented similar findings from the Muskegon River estuary of Lake Michigan during 2003 and 2004, documenting diel vertical migration for the first time in larval round gobies. We suggest vertical migration behavior may have allowed larval round gobies to be transported to and within the Great Lakes via ballast water and dispersed in the Great Lakes via advection of 6.5–8.5-mm long larvae at the surface. Based on our results, if ballast water was only taken on near the surface during daylight hours from May through September when larval round gobies were present, it would have mitigated the spread of round gobies throughout the Great Lakes.     

鱼友型水轮机研究进展及建议

鱼友型水轮机的研究旨在保证水轮机水力性能的前提下提高过机鱼的存活率。某些发达国家已投入一定的人力和财力进行了鱼友型水轮机的研究,取得了不少成果,部分成果已应用到水电站,而我国在该领域的研究还处于空白。本文对过机鱼损伤机理、鱼友型水轮机设计及水轮机过鱼试验等成果进行全面的归纳和总结,并对鱼友型水轮机的研究方向提出建议。     

基于鱼类栖息地需求的雅鲁藏布江中游环境流量计算

针对水利工程影响下,河道下游天然水文情势改变造成鱼类产卵场面积减小和质量降低等潜在生态问题,通过数值模拟与统计建立拉萨裸裂尻鱼产卵期栖息地适宜度模型,采用栖息地模拟法计算了雅鲁藏布江中游藏木水电站坝下米林—尼洋河汇口处38.9 km河段的环境流量。结果表明:拉萨裸裂尻鱼产卵期适宜水深为0.7～1.0 m,适宜流速为0.4～0.6 m/s;研究河段内拉萨裸裂尻鱼产卵期环境流量为432 m~3/s。     

我国淡水鱼流通组织模式评价与选择

结合实地调查,按组织化程度高低把我国淡水鱼流通组织模式分成了企业产运销一体化型、市场交易型和联盟合作型三种类型,并从质量保障能力、数量保障能力、成本竞争优势、快速供应市场能力、节能减排优势五个方面对各模式进行了评价,最后提出了针对大宗淡水鱼、特优淡水鱼以及品牌化淡水鱼流通的组织模式选择策略。     

Turbidity control and fisheries enhancement in a bottomland hardwood backwater system in Louisiana (U.S.A.)

In response to a noticeable decline in recreational fishing in the formerly productive Larto—Saline backwater complex of east central Louisiana, a study was begun to identify causative factors for the decline and to determine effective methods to remedy the problem. To this end, water quality and fisheries surveys were conducted in the system for the study period 1 July, 1981 to 30 June, 1989. Data collected during the early years of the study indicated chronically high turbidity (> 100 FTU) to be the major factor limiting game fish production. The high turbidity can be related to man-made alterations of natural flood patterns that had changed the major source of backwater flooding from Black River to the highly turbid Red River. In September, 1986, a construction project was undertaken to restore flood patterns to approximate natural conditions. Sampling subsequent to this construction has shown a significant decrease in turbidity and an increase in game fish production.     

Downstream Migration of the European Eel (Anguilla Anguilla) in the Elbe River,Germany: Movement Patterns and the Potential Impact of Environmental Factors

Recruitment of European eels (Anguilla anguilla) has declined to the extent that they have been added to the IUCN Red List of Threatened Species. Therefore, it is critical to ensure that eels complete their outward river migration in order to contribute to the available spawning stock. We conducted a 4‐year (2007–2011) telemetry study to understand the migratory behaviour and potential impact of environmental factors on the eel during this critical life stage. Out of 399 female eels tagged with acoustic transmitters, only 28% demonstrated clear downstream migratory behaviour. Fifty‐five percent were detected exhibiting no downstream migration behaviour and 17% were not detected at any monitoring station. Movement patterns of downstream‐migrating (silver) eels were characterized by nocturnal activity and seasonal migration, with distinct peaks in autumn and spring. Migration was often discontinuous and exhibited phases of active locomotion and expanded stopovers. The most important determinants of movement activity were water temperature, cumulative precipitation and moonlight, although the significance varied by season and location in the river basin. Our results evidence a discontinuous, stepwise migration over an extended period. Furthermore, our findings indicate that migration success depends on holding duration prior to tagging and environmental predictors with varying importance depending on the season, as well as the locations of capture, tagging and release. Copyright © 2015 John Wiley & Sons, Ltd.     

Gordleton磨坊小水电改造工程水能开发和环境影响评估

水能和环境影响的评估,对于判别英格兰新福里斯特区埃文河Gordleton磨坊重新安装一台改良水车或一台水轮机或一台阿基米德式螺旋水轮机的可行性和经济性是至关重要的。基于一个典型水文年份年平均径流量0.41m3/s且合理利用水资源的方案,Gordleton磨坊改造后的年电力输出为26000~30000kW·h。实地调查并记录了当前的环境变量,包括土地利用、植被、基层、水质、鱼类、无脊椎动物和噪音等。其中,鱼类洄游,特别是受法律保护的二龄鲑,将会受到工程影响,需要安装网格为1cm2的护鱼筛网并提供鱼道。噪音和振动也是主要的环境影响,采用隔音材料可以降低其负面作用。推荐采用0.15m3/s的旱季生态系统的补偿流量。     

The flood of the century on the River Oder: effects on the 0+ fish community and implications for floodplain restoration

In summer 1997, the flood of the century occurred on the River Oder in the Czech Republic, Poland and Germany. Effects of the summer flood on the 0+ fish community were evaluated at the Lower Oder in the Polish–German National Park. Fish were collected from different mesohabitats before the flood, at rising water levels and after the flood using Point Abundance Sampling by electrofishing. Flooding caused changes in local 0+ fish assemblages and partly affected the physical habitat structure. Two sandbars were formed by breaches in the dike system, replacing the former uniform river embankments. Under post‐flood conditions, diversity was increased in nearly all mesohabitats. ‘Wash‐out’ of 0+ fish was highest in poorly structured mesohabitats. Effects of the summer flood on eurytopic species were the most pronounced. We suggest that the progeny of rheophilic species were affected to a lesser extent by flooding because of their adaptation to variable flow conditions. Furthermore, rheophilic 0+ fish were able to colonize the newly created mesohabitats and, thus, benefited from the increased habitat heterogeneity after the flood. In this context, implications for floodplain restoration are discussed. Copyright © 2001 John Wiley & Sons, Ltd.