Perch larvae (Perca fluviatilis L.) survive better in dilute sea water

Larvae of perch (Perca fluviatilis L.) reared in tanks for 27 days survived better in lake water to which 2% of artificial sea water had been added (46.6% average survival rate) than in lake water only (13.5% survival). One week after hatching, over 90% of the larvae had their guts filled in all tanks. During the following week the populations divided into floaters (fish with an inflated swimbladder) and sinkers (fish apparently lacking a functional swim-bladder). Although they continued feeding, sinkers remained smaller than floaters and most of them died.     

Living a century in warm thermal conditions: introduced populations of Pumpkinseed (Lepomis gibbosus) inhabiting the Iberian Peninsula (Spain) show reduced adaptation to North American winter conditions

In this study, we demonstrate that non-native Pumpkinseed (Lepomis gibbosus) introduced into Spanish water-bodies almost 100 years ago have a reduced capacity to tolerate winter conditions typically experienced by northern native populations. Overwinter survival and changes in lean weight and lipid content of Pumpkinseed from artificial colonies established from two Canadian and two Iberian source populations were compared under winter conditions typically experienced in the northern native range. Adult survival in outdoor ponds was higher in Canadian populations (68 and 78 %) than Iberian populations (31 and 49 %). Under simulated winter conditions in the laboratory, juvenile Iberian Pumpkinseed experienced higher mortality earlier in the winter period than Canadian populations. Lipid content of Iberian juveniles decreased on average by 49 % during the first half of the winter, while that of Canadian populations decreased by only 12–20 %. These results indicate that Iberian Pumpkinseed have lower tolerance of winter conditions relative to native Canadian populations, and suggest that relatively short exposure to warm climates can result in adaptive change in the physiology and bioenergetics of wild fish populations.     

Investigating the presence of organochlorine pesticides and polychlorinated biphenyls in wild and farmed gilthead sea bream (Sparus aurata) from the Western Mediterranean sea

The presence of organochlorine pesticides and polychlorinated biphenyls in wild and farmed gilthead sea bream (Sparus aurata) from the Western Mediterranean, Spain, is investigated. These pollutants were determined in white and red muscle and liver by gas chromatography coupled to tandem mass spectrometry. Contaminant profiles present in both wild and farmed fish tissues include DDTs, PCBs and HCB. The highest concentrations of contaminants were found in liver, and an increase in pollutant levels was observed in autumn, before spawning. This fact is explained in light of increased food intake when sea water temperatures increase. Gilthead sea bream from Western Mediterranean populations showed significantly higher concentrations of DDTs and PCBs than farmed fish from the same area. This fact is attributed to the low level of organochlorine contaminants present in fish feed supplied to the cultured fish. The diet is highlighted as an important factor in understanding differences observed in organochlorine pollutants levels of fish tissues.     

Biomarker responses and genotoxicity in the mud snail (Bullacta exarata) as indicators of coastal contamination

In the present study different biomarker responses and genotoxicity were determined in wild mud snails (Bullacta exarata) collected from 3 sampling sites in Bohai Bay in northeastern China, which is a region that is under considerable anthropogenic influence. Significant spatial variability of superoxide dismutase (SOD) and metallothionein (MT)-like proteins were recorded, while glutathione transferase (GST), catalase (CAT), and vitellin-like proteins (Vn's) were not observed. Furthermore, genomic DNA that was amplified with 4 fluorescence-labeled primer pairs showed variable genetic distances among the 3 wild mud snail populations found in Bohai Bay, which may be correlated with differences in the types of environmental genotoxicants, such as heavy metals and polycyclic aromatic hydrocarbons. This multi-biomarker approach provided an improved understanding of the potential toxicological impact of contaminated sediments on benthic organisms.     

基于COI基因序列的太湖新银鱼遗传多样性

利用线粒体细胞色素C氧化酶I(COI)分子标记分析长江中下游太湖新银鱼(Neosalanx taihuensis)8个地理种群132个样本的遗传多样性.该基因630 bp片段的碱基序列共检出8个核苷酸变异位点(变异率1.27%),其中局域性单倍型居多(75%),群体单倍型多样性较高(h=0.576±0.036),而核苷酸多样性较低(π=0.00112±0.00204).不同地理种群遗传多样性差异显著:有人工移植历史种群遗传多样性较高、隔离度较高的种群遗传多样性较低,但大部分的遗传变异来自于种群内(54.83%),反映出地理隔离和人为干扰对太湖新银鱼遗传格局影响显著.研究表明COI基因适于银鱼科鱼类物种鉴别和系统发育研究,同时可为同种种群间遗传关系分析提供一定的信息.     

The particulate load of the Red River,St Ives Bay: Its geochemical composition and the effect of its discharge plume on the behaviour of a resident wild dolphin

A resident wild dolphin is reported to avoid the discharge plume from the Red River which empties into the northern end of St Ives Bay. The river effluent is found to contain a high load of finely divided metalliferous particles rich in iron but also containing significant amounts of Sn, As, Cu and Zn. It is suggested that the echo-location system and/or chemosensory system of the dolphin may be affected by this discharge causing the animal to avoid the area of the effluent.     

Hyperactivity and changed diurnal activity in flounders,Platichthys flesus,exposed to DDT

Flounders (Platichthys flesus), which had been given oral doses of DDT, developed hyperactivity and abnormal diurnal activity 5–7 weeks after the dosage of DDT was terminated. For the flounder given the highest dose (12.5 mg DDT kg^?1 fresh body weight) a more than 20-fold increase in swimming activity was recorded. The levels of DDT found in various organs (axial muscle, liver and brain) are compared with levels of DDT found in wild populations of fish from the Baltic Sea. The results are also discussed in relation to results obtained in a parallel study on the physiological effects of DDT on the flounder.     

Evidence of a high percentage of intersex in the Mediterranean swordfish (Xiphias gladius L.)

The first evidence of the presence of intersexuality in a wild population of Mediterranean swordfish (Xiphias gladius L.) is reported. Forty of 162 specimens (25%) macroscopically classified as males, showed the presence of female germ cells within the testes. In two specimens grouped previtellogenic oocytes were present; all the other specimens possessed single scattered previtellogenic oocytes. The presence of vitellogenin was demonstrated immunohistochemically in the liver of both intersex and normal males. These findings could be due to the exposure to oestrogen-mimicking substances.     

Water quality and Cryptosporidium distribution in an upland water supply catchment,Cumbria, UK

Four micro‐catchment (MC) areas were identified to represent the main terrain types of a remote, sparsely populated upland valley catchment of 18 km² in Cumbria, UK. These were improved land with good grazing (IB), steeply sloping land with rough grazing (SG), wet moorland with sparse grazing (WM) and enclosed woodland that excluded livestock and deer (EW). Each MC contained the origin of a small stream that flowed into Swindale Beck, the river draining the valley. The water quality during the 14‐month study, as judged by chemical and physical parameters, was excellent, but it could not be regarded as pristine because of the frequent presence of Cryptosporidium oocysts arising from livestock and wild mammal faeces. Oocysts (0·2–5·6 l^?1) detected by genus‐specific immunofluorescent antibody were found in 32% of 188 water samples tested: ranking order EW 44%, IB 34%, Beck 30%, SG and WM 26%. Similarly, oocysts were identified in 9·5% of 1730 faecal samples. Small wild mammals (28%), calves (15·7%) and lambs (8·1%) were the dominant sources, whereas adult livestock (1·8%) and large wild mammals (4·8%) were less important. Autumn showed the highest occurrence of oocysts for both water and faecal samples. No hydrological controls were found to have a significant impact on the occurrence or concentration of oocysts in the main river or in the MCs, suggesting that their presence is controlled by seasonal changes in pathogen prevalence in the animal reservoir. Copyright © 2006 John Wiley & Sons, Ltd.     

Biochemical genetic study of European whitefish (Coregonus lavaretus) in Lake Mondsee,Upper Austria

Mature coregonids of Lake Mondsee were caught during spawning time on three known spawning sites. The aim of the study was to reveal whether the three stocks are reproductively isolated, and in consequence to decide whether they should be managed as separate stocks or as one panmictic population.Fish were examined morphologically and their tissue samples were examined electrophoretically for the enzyme products of 37 genetic loci.The gill-raker numbers (28–40) and electrophoretic alleles were typical for European whitefish,Coregonus lavaretus. No genetic differentiation (Nei's genetic distance D = 0.000) was found between the three samples studied. The genetic characteristics of the Lake Mondsee whitefish population, based on pooled genetic data, was compared to several other European whitefish populations. The average heterozygosity (6.5%) was high as usually in whitefish; genetic distances between the Lake Mondsee and three other European whitefish populations were within the range reported for the geographically distant populations of the species. Management implications of the results are briefly discussed.Contribution No. 21 in the Program of Joint Investigation of Holarctic Fishes among Russia, Canada, Finland, and Poland     

Ecological impacts of tributyltin on estuarine communities in the Hastings River, NSW Australia

Oyster (Saccostrea commercialis) biomonitoring, assessment of oyster and gastropod (Bembicium auratum) abundance, and gastropod imposex were used to measure the significance of tributyltin (TBT) contamination in an intertidal mangrove forest. We studied the bioavailable levels of TBT in oysters approximately 1 km downstream and 2 km upstream from a TBT waste disposal site. We found observable declines in the abundance of oysters and gastropods correlated with the bioavailable TBT and these findings were confirmed by mapping oyster beds. Oyster cover near the disposal site ranged from 0% to 5% while downstream and upstream populations ranged in cover from 25–50% to 5–25%, respectively. Similarly, gastropod abundances at the disposal site were only 7% of the downstream population and 17% of the upstream population. Imposex was present in 90% of female B. auratum from populations near the disposal site but this effect declined more sharply than the population level effects.     

Estuarine fish health assessment: evidence of wastewater impacts based on nitrogen isotopes and histopathology

Sewage effluent is a powerful agent of ecological change in estuaries. While the effects of sewage pollution on water quality are usually well documented, biological responses of exposed organisms are not. We quantified health impacts in the form of pathological tissue changes across multiple organs in estuarine fish exposed to elevated levels of treated wastewater. Structural pathologies were compared in wild populations of four fish species from two subtropical estuaries on the east coast of Australia that differ substantially in the amount of direct wastewater loadings. Uptake of sewage-derived nitrogen by fish was traced with stable nitrogen isotopes. Pathologies were common in the liver, spleen, gill, kidney and muscle tissues, and included granulomas, melanomacrophage aggregates, and multiple deformities of the gill epithelia. Tissue deformities were more frequent in fish exposed directly to wastewater discharges. Mullet (Valamugil georgii) were most affected, with only a single specimen free of pathologies in the sewage-impacted estuary. Similarly, in those fish that had structural abnormalities, more deformities were generally found in individuals from sites receiving sewage. These spatial contrasts in impaired fish health correspond to significantly enriched delta15N values in fish muscle as a consequence of fish assimilating sewage-N. Overall, the pattern of lower health and enriched delta15N values in fish from sewage-impacted areas suggests that organism health is lowered by sewage inputs to estuaries. Measurements of organism health are required to understand the effects of sewage on estuarine ecosystems, and histopathology of fishes is a powerful tool to achieve this.     

Genetic diversity and metal tolerance of two marine species: a comparison between populations from contaminated and reference sites

Long-term contamination of the marine environment surrounding a lead smelter offered a unique opportunity to examine how pollutants might have acted to alter genetic characteristics of populations of organisms in the receiving system. This study used random amplified polymorphic DNA analysis to compare the genetic diversity of populations of the prawn, Leander intermedius, and the isopod, Platynympha longicaudata from the smelter discharge site with reference populations. The genetic diversity of the prawn population from the smelter discharge site (Port Pirie) was lower than that found in one reference population, and not significantly different from the other two reference populations. Genetic diversity of the Port Pirie population of isopods was found to be significantly lower than that of all reference populations. Prawns and isopods were also exposed to metal mixtures in the laboratory in a similar ratio to that found in seston near the smelter effluent discharge site. Both pre-exposed and reference populations of prawns tolerated elevated levels of metals and exhibited no significant difference in response. This contrasted with the isopods, with the pre-exposed isopod population showing greater tolerance to elevated metal levels compared with the reference population. These results highlight the need to include a number of reference populations for comparative purposes in genetic diversity studies, and the need to assess the influence of pollution on the genetic diversity of more than one species if genetic diversity analyses are to be used to gauge remediation success.     

Relationship Between Oil Exposure and Reproductive Parameters in Fish Collected Following the Exxon Valdez Oil Spill

Following the Exxon Valdez oil spill (EVOS) in 1989, the effect of oil exposure on reproductive parameters was investigated in wild populations of female dolly varden, yellowfin sole, and pollock. Exposure to oil was the highest in the first year of sampling and decreased in the subsequent years of sampling. Both positive and negative correlations between reproductive parameters and indices of exposure were detected in varying degrees for all three species. Reproductive parameters were not measured in the first year of sampling. For those parameters found to be significantly correlated to oil exposure, an exponential regression function was used to project reproductive parameters of fish sampled in the first year of the spill. A higher proportion of dolly varden sampled in 1989 were projected to have depressed plasma estradiol-17β compared to the fish sampled in 1990.     

Enviromental genotoxicity evaluation: Bayesian approach for a mixture statistical model

 The data analyzed in this paper are part of the results described in Bueno et al. (2000). Three cytogenetics endpoints were analyzed in three populations of a species of wild rodent – Akodon montensis – living in an industrial, an agricultural, and a preservation area at the Itajaí Valley, State of Santa Catarina, Brazil. The polychromatic/normochromatic ratio, the mitotic index, and the frequency of micronucleated polychromatic erythrocites were used in an attempt to establish a genotoxic profile of each area. It was assumed that the three populations were in the same conditions with respect to the influence of confounding factors such as animal age, health, nutrition status, presence of pathogens, and intra- and inter-populational genetic variability. Therefore, any differences found in the endpoints analyzed could be attributed to the external agents present in each area. The statistical models used in this paper are mixtures of negative-binomials and Poisson variables. The Poisson variables are used as approximations of binomials for rare events. The mixing distributions are beta densities. The statistical analyzes are under the bayesian perspective, as opposed to the frequentist ones often considered in the literature, as for instance in Bueno et al. (2000).     

Use of Chemotaxonomy To Study the Influence of Benzalkonium Chloride on Bacterial Populations in Biodegradation Testing

Contradictory results are reported for the behaviour of quaternary ammonium compounds (QACs) in sewage treatment plants (STPs). QACs may sorb onto activated sludge. Only little information is available with respect to effects of QACs against bacteria in STPs. Only 5 to 15 % of bacteria present in sewage sludge can be detected by means of culture dependent microbiological methods. The shift of the bacterial populations due to effects of test compounds have not been studied up to now with culture independent methods. The microbial populations shift was studied in situ using culture independent chemotaxonomy profiling ubiquinones and polyamines. Additionally, toxic effects of QACs against bacteria present in the test vessels of the Zahn‐Wellens test (OECD 302 B) were assessed with a toxicity control in the test. The ubiquinone profiles representing changes in Gram‐negative populations mainly showed that the activated sludge was affected only in test vessels containing benzalkonium chloride. According to chemotaxonomy Acinetobacter or/and some members of Pseudomonas spp. have been selected by benzalkonium chloride after some adaptation period (8 to 12 days).     

Elucidating transmission parameters of African swine fever through wild boar carcasses by combining spatio-temporal notification data and agent-based modelling

Mechanistic epidemiological modelling has a role in predicting the spatial and temporal spread of emerging disease outbreaks and purposeful application of control treatment in animal populations. Especially in the case of infectious diseases newly emerging in an ecological habitat, lack of knowledge may hamper direct parameterisation of model algorithms. Along with experimental studies observational data is usually based on case notifications. These data are widely acknowledged as having “biological precision” due to e.g. convenient sampling procedures, host or human activity patterns or diagnostic limitations under field conditions. Nevertheless, the data comprises the complex spatio-temporal distribution patterns of the infection. In the literature, this data value is non-systematically used to inform model development although the need for and value of the data is well recognised. Here we address the newly emerging epidemic of African swine fever spreading in Eurasian wild boar using an existing spatio-temporally explicit individual-based model of wild boar. The disease etiology required the implementation of a sub-model regarding transmission by carcasses left after infected individuals have died. However, the experimental evidence about the mechanism involved in carcass-mediated spread of the infection still has to be established. We propose a mechanistic quantitative procedure to optimise calibration of several uncertain parameters based on the spatio-temporal model output from the simulation environment and the spatio-temporal case data of infectious disease notifications. The best agreement with the spatio-temporal spreading pattern was achieved by parameterisation that suggests ubiquitous accessibility to carcasses but with marginal chance of being contacted by conspecifics e.g., avoidance behaviour. The parameter estimation procedure is fully general and applicable to problems where spatio-temporal explicit data recording and spatial-explicit dynamic modelling was performed.     

鲚属两种群的形态变异及综合判别

测量了代表刀鲚种群和湖鲚种群形态特征的传统可量性状和框架参数,采用主成分分析法和逐步判别法,对它们进行形态综合分析.结果表明:两种群的形态差异主要是受额部有鳞部最前缘到背鳍起点的距离所影响的;所有25个形态参数数据判别分析,表明两种群形态差异极显著(P<0.01),判别准确率100％;利用挑选后的9项参数判别分析,表明两种群的形态差异极显著(P<0.01),判别准确率P1是95％-100%,P2是95.2％-100％,综合判别率为97.5％.对各形态参数进行单因子方差分析,计算各参数的差异系数,根据Mayr提出的75％规则,认为它们的形态差异仍然是种内不同地理种群的差异,还没有上升到亚种水平.     

Population similarity analysis of indicator bacteria for source prediction of faecal pollution in a coastal lake

Biochemical fingerprinting (BF) databases of 524 enterococci and 571 Escherichia coli isolates and an antibiotic resistance analysis (ARA) database comprising of 380 E. coli isolates from four suspected sources (i.e. dogs, chickens, waterfowls, and human sewage) were developed to predict the sources of faecal pollution in a recreational coastal lake. Twenty water samples representing four sampling episodes were collected from five sites and the enterococci and E. coli population from each site were compared with those of the databases. The degree of similarity between bacterial populations was measured as population similarity (Sp) coefficient. Using the BF-database, bacterial populations of waterfowls showed the highest similarity with the water samples followed by a sewage treatment plant (STP). Higher population similarities were found between samples from STP and water samples especially at two sites (T2 and T3) which were located near the sewerage pipes collecting wastewater from the study area. When using the ARA-database, the highest similarity was found between E. coli populations from STP and water samples at sites T2 and T4. Both faecal indicators and as well as methods predicted human faecal pollution, possibly through leakage from submerged sewerage pipes. The results indicated that the Sp-analysis of faecal indicator bacterial populations from suspected sources and water samples can be used as a simple tool to predict the source(s) of faecal pollution in surface waters.