家蝇幼虫的综合开发利用

家蝇幼虫的利用前景十分广阔,本文主要介绍了家蝇幼虫在动物饲料、食用、几丁质、抗菌物质以及凝集素等方面的开发利用     

Influence of Hydrologic Conditions of the Lower Ob Floodplain on Reproduction in Coregonids

The influence of the water level in the period of the open river channel and the duration of lower floodplain inundation on the feeding conditions, abundance, and population state of coregonids in the Lower Ob was investigated. The long-term dynamics of catches of some coregonid species was analyzed and compared with changes in the hydrologic conditions in the floodplain. The relationship between basic hydrologic conditions in the Lower Ob (water level in the period of the open channel, the duration of the lower floodplain inundation), the coregonid population sizes, the state of spawners, and the size of catches is demonstrated.     

Contrasting effects of black carbon amendments on PAH bioaccumulation by Chironomus plumosus larvae in two distinct sediments: role of water absorption and particle ingestion

Two sediment matrices with different characteristics were amended with chars from different sources for bioaccumulation assay with filter-feeding Chironomus plumosus larvae. Chars greatly decreased porewater concentrations of PAHs (C_iw) measured using polyethylene devices in sediments. In organic rich sediment matrix-based systems where suspended char particles were absent, PAH concentrations in larvae (C_iB) were significantly correlated with C_iw, and there was no difference in water-based bioaccumulation factors (BAFs) between different treatments, suggesting that water absorption was the main contaminant uptake route for larvae. In organic poor sediment matrix-based systems where suspended char particles were present, poor Pearson correlation between C_iB and C_iw was found, but there was a significant linear increase of BAF values with char contents, which indicated that ingestion of suspended char particles could also be important for PAH bioaccumulation. Therefore, we need to rethink of the effectiveness and risks for the application of black carbon to sediment/soil remediation.     

长江下游刀鲚生物学及最大持续产量研究

对1993~2002年长江下游刀鲚的生物学特征、单船产量变化及最大持续产量进行了研究。结果表明,汛期刀鲚平均体长为29.19 cm,平均体重为94.33 g;体长和体重呈幂函数相关,拟和方程为Y= 0.004 8X2.906 9,丰满度系数为0.379。绝对怀卵量平均为23 695粒,相对怀卵量平均为229粒/g体重,成熟卵卵径平均为0.77毫米;绝对怀卵量与体长的关系式为Y= 0.017 2X4.101,与体重的关系式为Y= 305X-5 410.1。汛期种群以2冬龄为主。研究期内刀鲚平均汛期单船总产为393.14 kg;长江下游刀鲚年均捕捞量为891.51 t,应用Schaefer模式估算最大持续产量为2 061.81 t。与历史资料相比,刀鲚个体小型化明显,种群结构简单化、低龄化,资源急剧下降。     

Ecological Integrity Assessment of Lakes Using Fish Communities: An Example from Traunsee Exposed to Intensive Fishing and to Effluents from the Soda Industry

In order to analyse potential influences of soda industryeffluents on the ecological integrity of Traunsee (TS) weinvestigated the fish community of the lake in comparison witha reference lake (Hallstättersee HS) and used a reconstructionfrom the (older) literature concerning the original speciescomposition of Traunsee. Published `Index of Biotic Integrity(IBI)' metrics were considered to be of limited value due tothe relatively low species number in the oligotrophic, Alpinelake. Therefore we included, in addition to speciescomposition, studies on egg distribution, larval fishdensities, life-history parameters (i.e. growth, maturity,fecundity, age and size composition), stress levels and heavymetal content of the dominant whitefish (Coregonuslavaretus), as well as overall fish density and biomass (usinghydroacoustics) to assess the ecological status of the fishcommunity. Two of the original 18 species have disappearedfrom the lake, presumably in connection with the introductionof non-native eel (Anguilla anguilla) and theconstruction of a power plant in the outflow. Silt from grindedlimestone together with highly alkaline pore waters is emittedvia industrial wastewater from Sodaworks and covers part of thelake bottom. We observed that eggs of whitefish were spawnedmainly in the main inflowing river and close to the shore, thusavoiding the silty areas and making the anticipated damage tothe reproductive potential of whitefish neglectable. This wascorroborated by larval surveys done weekly on both lakes fromJanuary to May, which showed halve the density of whitefishlarvae in TS compared to HS. Estimates of potentially spawningfish from hydroacoustic surveys resulted in a ratio of 1(TS) :3 (HS). Analysis of whitefish revealed that they are growingfaster in TS and have higher fecundity leading to somecompensation of lower abundance. High levels of fishing in TSmight have led to this pattern and to depressed yields asindicated by the age composition. Level of oxidative stress andheavy metal content were not discernible from the referencelake. Therefore we concluded that negative impacts on theecological status of the fish community resulted from fisheriesmismanagement and a power plant situated in the outflow of thelake, considered to have damaged spawning places for somespecies, but not from soda industry effluents.     

Long-term assessment of insecticides treatments in West Africa: aquatic entomofauna

For the control of the Onchocerca volvulus vector in West Africa, up to 18,000 km of rivers from 1975 and up to 50,000 km from 1989 had been partly sprayed weekly with insecticides as part of the Onchocerciasis Control Programme (OCP). To evaluate the possible short-term and long-term effects of the application of insecticides on the non-target fauna, an aquatic monitoring programme was set up during the initial phase of the programme. By analysing the invertebrate data, which were collected using various sampling strategies from four different countries between 1977 and 1996, this paper evaluates the long-term changes of the invertebrate populations with respect to their taxonomic composition as well as their trophic structures. The discussed results of the applied numerical analysis strategy suggest that neither the taxonomic nor the trophic structures are greatly altered from the range of biological, flow-related variation that normally occurs in the studied river systems. This allows us to conclude that the biological variation found here is ecologically acceptable.     

Comparative toxic effects of formulated simazine on Vibrio fischeri and gilthead seabream (Sparus aurata L.) larvae

The use of Early Life Stage (ELS) tests is a useful tool in risk assessment. The purpose of this study was to compare the sensitivity of the seabream (Sparus aurata) larvae with the extensively used Microtox^® test on a commercial formulation containing simazine, an s-triazine herbicide. To this end, survival, growth and histopathological changes displayed by seabream yolk sac larvae exposed during 72 h post-hatching to nominal concentrations of the commercial preparation up to its saturating concentration in water, and bioluminescence of the marine bacteria Vibrio fischeri (Microtox^®) were studied. Survival of larvae after three days of exposure was significantly reduced in the highest (4.5 mg/l) concentration, but no effects on growth were found in any of the simazine treatments. The 72 h LC50 value for yolk sac larvae was estimated as 4.19 mg/l. Commercial grade simazine did not exert any significant toxicity to the marine bacterium V. fischeri at the concentrations tested.     

Response of antioxidase in viscera of Pagrosuma major larvae to water soluble fraction of hydrocarbons in No.0 diesel oil

Pagrosomus major larvae were to the water-soluble fraction of hydrocarbon in No.0 diesel oil(corresponding to No.2 fuel oil) at concentration of 0,0.17,1.22 and 8.82mg/L for up to 15 days.Larvae were sampled on days 9 and 15 of the experiment.Supernatants of viscera tissue extractions were assayed for biochemical response in terms of oxidative stress-superoxide dismutase(SOD),activity of selenium-dependant glutathione peroxidase(Se-GPx) and catalase(Ca),and the concentration of reduced glutathione(CSH).On day 9 of exposure ,statistically significant dose-related increases in Se-GPx and SOD activity,and GSH concentration were observed in all cases except for Se-GPx activity under the highest dosage of hydrocarbon.However,on day 15 of exposure, a similar dose-related in all cases except for Se-GPx activity under the highest dosage of hydrocarbon.However,on day 15 of exposure, a similar dose-related response was only observed for Se-GPx activity.GSH concentration decreased and SOD activity showed no statistical difference as compared to controls.However, a significant decrease in compared to day 9 Se-GPx activity and GSH concentration, in contrast to increase SOD activity at day 15 as indicates an accelerated accumulation of H2O2 and potential oxidative damage under long term exposure of larvae to hydrocarbons.No statistical changes were observed in Ca activity throughout the experiment, possibly owing to the high efficiency of Se-GPx.A recovery experiment was performed on indicating that the response of antioxidants measured tending to returm to return to their control levels.These results prove the function of the antioxidant defense system of the larvae to the water-soluble fraction of hydrocarbons in No.0 diesel oil.     

Response of antioxidase in viscera of Pagrosuma Major larvae to water soluble fraction of hydrocarbons in No.0 diesel oil

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