Downstream migration of European lake trout, Salmo trutta f. lacustris L., and resident brown trout, Salmo trutta f. fario L., progeny in a Lake Constance affluent river     

U. H. Schulz 《Fisheries Management and Ecology》1999,6(3):187-194

Abstract The local migratory behaviour of lake trout, Salmo trutta L., and resident brown trout, S. trutta L., progeny from an inflowing stream of Lake Constance was compared. No differences were detected with respect to emigration rate (3.5% and 4.2% for lake trout and resident trout, respectively), rate of residency (6.8% and 8.2% for lake trout and resident trout, respectively) and rate of survival (12.3% and 12.1% for lake trout and resident trout, respectively) one year after stocking. Some of the resident brown trout offspring became migrants and vice versa . The results indicate that the progeny of riverine brown trout contribute considerable numbers to lake trout stock.  相似文献   

Finding suitable growth models for turbot (Scophthalmus maximus L.) in aquaculture 1 (length application)          下载免费PDF全文

Vincent Lugert  Jens Tetens  Georg Thaller  Carsten Schulz  Joachim Krieter 《Aquaculture Research》2017,48(1):24-36

Growth data of two different commercial turbot (Scophthalmus maximus) strains reared in recirculating aquaculture systems were analysed with the aim to determine the most suitable model for turbot. To assess the model performance three different criteria were used: (1) The mean percentage deviation between the estimated length and actual length; (2) the residual standard error with corresponding degrees of freedom and (3) the Akaike information criterion. The analyses were carried out for each strain separately, for sexes within strains and for a pooled data set containing both strains and sexes. We tested a pre‐selection of six models, containing three to four parameters. Models were of monomolecular shape or sigmoid shape with a flexible point of inflection including the special case of monomolecular shape in defined cases of their parameters. The 4‐parametric Schnute model achieved best fit in 62% of all cases and criteria tested, followed by the also 4‐parametric generalized Michaelis–Menten equation in 48% and the 4‐parametric Janoschek model (38%). The von Bertalanffy growth function achieved only 29%, Brody 24% and a new flexible function 19% best fit. In a 1–1000 day growth‐simulation sigmoid shaped curves were produced by the Schnute model in 71% of cases. The Janoschek and the Michaelis–Menten model each produced sigmoid curves in 57% of all cases. This indicates that a flexible 4‐parametric function reflects the growth curve of turbot the best and that this curve is rather sigmoid than monomolecular shaped.  相似文献   

Genetic diversity and population structure of burbot Lota lota in Germany: Implications for conservation and management     

Maj Wetjen  Thomas Schmidt  Anne Schrimpf  Ralf Schulz 《Fisheries Management and Ecology》2020,27(2):170-184

The genetic structure of the gadiform fish species, burbot Lota lota L., was investigated across Germany to derive management options for facilitating the preservation of genetic diversity. Sequence analysis of the mitochondrial control region (n = 244) and microsatellite analysis (n = 861) of specimens from 20 sites revealed genetic structuring between major river basins, and particularly between lake and river habitats. The admixture zone between the Eurasian and West European phylogenetic clades in Lake Constance was confirmed and expanded to include the drainage basins of the rivers Rhine and Schlei/Trave. Haplotype distribution and private haplotypes in single river basins indicated population differentiation and imply that German burbot constituted an important part of the entire species' diversity. The derived genetic structuring has implications for future stocking programmes and the preservation of the adaptive potential of burbot, a guiding species for oligotrophic lakes in Europe.  相似文献   

Successful rearing of whiteleg shrimp Litopenaeus vannamei larvae fed a desiccation‐tolerant nematode to replace Artemia          下载免费PDF全文

L.H. Seychelles  S. Happe  E. Palacios  M. Ludwig  S. Hollmer  R.‐U. Ehlers  C. Schulz  L. Mercier 《Aquaculture Nutrition》2018,24(2):903-910

The nematode Panagrolaimus sp. was tested as live feed to replace Artemia nauplii during first larval stages of whiteleg shrimp Litopenaeus vannamei. In Trial 1, shrimp larvae were fed one of four diets from Zoea 2 to Postlarva 1 (PL1): (A) Artemia nauplii, control treatment; (NC) nematodes enriched in docosahexaenoic acid (DHA) provided by the dinoflagellate Crypthecodinium cohnii; (N) non‐enriched nematodes; and (Algae) a mixture of microalgae supplemented in C. cohnii cells. In Trial 2, shrimp were fed (A), (NC) and a different treatment (NS) with nematodes enriched in polyunsaturated fatty acids (PUFAs) provided by the commercial product S.presso^®, until Postlarva 6 (PL6). Mysis 1 larvae fed nematodes of the three dietary treatments were 300 μm longer (3.2 ± 0.3 mm) than control larvae. At PL1, control shrimp were 300 μm longer (4.5 ± 0.3 mm) than those fed DHA‐enriched or PUFAs‐enriched nematodes. No differences were observed in length and survival at PL6 between control larvae and those fed DHA‐enriched nematodes (5.1 ± 0.5 mm; 33.1%–44.4%). Shrimp fed microalgae showed a delay in development at PL1. This work is the first demonstration of Panagrolaimus sp. suitability as a complete substitute for Artemia in rearing shrimp from Zoea 2 to PL6.  相似文献   

Reinoculation elucidates mechanisms of bacterial community assembly in soil and reveals undetected microbes     

Davide Francioli  Elke Schulz  Witoon Purahong  François Buscot  Thomas Reitz 《Biology and Fertility of Soils》2016,52(8):1073-1083

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The EFSA quantitative approach to pest risk assessment – methodological aspects and case studies          下载免费PDF全文

G. Gilioli  G. Schrader  J.‐C. Grégoire  A. MacLeod  O. Mosbach‐Schulz  T. Rafoss  V. Rossi  G. Urek  W. van der Werf 《EPPO Bulletin》2017,47(2):213-219

A new method for pest risk assessment and the identification and evaluation of risk‐reducing options is currently under development by the European Food Safety Authority (EFSA) Plant Health Panel. The draft method has been tested on pests of concern to the European Union (EU). The method is adaptable and can focus either on all the steps and sub‐steps of the assessment process or on specific parts if necessary. It is based on assessing changes in pest population abundance as the major driver of the impact on cultivated plants and on the environment. Like other pest risk assessment systems the method asks questions about the likelihood and magnitude of factors that contribute to risk. Responses can be based on data or expert judgment. Crucially, the approach is quantitative, and it captures uncertainty through the provision by risk assessors of quantile estimates of the probability distributions for the assessed variables and parameters. The assessment is based on comparisons between different scenarios, and the method integrates risk‐reducing options where they apply to a scenario, for example current regulation against a scenario where risk‐reducing options are not applied. A strategy has been developed to communicate the results of the risk assessment in a clear, comparable and transparent way, with the aim of providing the requestor of the risk assessment with a useful answer to the question(s) posed to the EFSA Plant Health Panel. The method has been applied to four case studies, two fungi, Ceratocystis platani and Cryphonectria parasitica, the nematode Ditylenchus destructor and the Grapevine flavescence dorée phytoplasma. Selected results from these case studies illustrate the types of output that the method can deliver.  相似文献   

Analysis of soil microbial communities based on amplicon sequencing of marker genes     

Anne?Sch?ler  Samuel?Jacquiod  Gisle?Vestergaard  Stefanie?Schulz  Michael?SchloterEmail author 《Biology and Fertility of Soils》2017,53(5):485-489

The use of cultivation independent methods has revolutionized soil biology in the last decades. Most popular approaches are based on directly extracted DNA from soil and subsequent analysis of PCR-amplified marker genes by next-generation sequencing. While these high-throughput methods offer novel possibilities over cultivation-based approaches, several key points need to be considered to minimize potential biases during library preparation and downstream bioinformatic analysis. This opinion paper highlights crucial steps that should be considered for accurate analysis and data interpretation.  相似文献   

Feasibility of Locating Leakages in Sewage Pressure Pipes Using the Distributed Temperature Sensing Technology     

Benjamin Apperl  Alexander Pressl  Karsten Schulz 《Water, air, and soil pollution》2017,228(2):82

The cost effective maintenance of underwater pressure pipes for sewage disposal in Austria requires the detection and localization of leakages. Extrusion of wastewater in lakes can heavily influence the water and bathing quality of surrounding waters. The Distributed Temperature Sensing (DTS) technology is a widely used technique for oil and gas pipeline leakage detection. While in pipeline leakage detection, fiber optic cables are installed permanently at the outside or within the protective sheathing of the pipe; this paper aims at testing the feasibility of detecting leakages with temporary introduced fiber optic cable inside the pipe. The detection and localization were tested in a laboratory experiment. The intrusion of water from leakages into the pipe, producing a local temperature drop, served as indicator for leakages. Measurements were taken under varying measurement conditions, including the number of leakages as well as the positioning of the fiber optic cable. Experiments showed that leakages could be detected accurately with the proposed methodology, when measuring resolution, temperature gradient and measurement time were properly selected. Despite the successful application of DTS for leakage detection in this lab environment, challenges in real system applications may arise from temperature gradients within the pipe system over longer distances and the placement of the cable into the real pipe system.  相似文献   

Population structure and genetic diversity in elite sugar beet germplasm investigated with SSR markers     

Jinquan Li  Britta Schulz  Benjamin Stich 《Euphytica》2010,175(1):35-42

The assessment of genetic diversity and structuration of germplasm is essential for the efficient organization of breeding material. The objectives of the study were to (i) examine the population structure of elite sugar beet germplasm, (ii) investigate genetic diversity within and among subgroups of elite sugar beet germplasm, and (iii) assess the extent of linkage disequilibrium (LD) within elite sugar beet germplasm. A total of 111 and 178 inbred lines from the seed and pollen parent (SP and PP) heterotic gene pools, respectively, which had been genotyped with 23 SSR markers, were used in this study. Two distinct subgroups were detected within the entire germplasm set by STRUCTURE and principal coordinate analysis (PCoA). This observation was not expected because the SP heterotic pool of sugar beet was developed out of the PP heterotic pool in the late 1970s. Our observation of high LD in elite sugar beet germplasm suggests that association mapping will be possible in the examined germplasm set using a relatively low numbers of markers. However, to reduce the problem of false-positive marker-phenotype association, it might be necessary to examine the subgroups separately or apply association mapping methods which take into account this structure.  相似文献   

Measurement of digestibility in agastric fish based on stripping method – apparent nutrient,energy and amino acid digestibilities of common feed ingredients for carp diets (Cyprinus carpio)          下载免费PDF全文

M.C. Heinitz  A. Lemme  C. Schulz 《Aquaculture Nutrition》2016,22(5):1065-1078

Apparent nutrient, energy and amino acid (AA) digestibilities of wheat starch (WS), corn starch (CS), pea protein concentrate (PPC), soy protein concentrate (SPC), corn gluten meal (CGM) and soybean meal (SM) were assessed indirectly in common carp by applying the marker‐based indicator method. Each test diet consisted of 70% reference diet and 30% test ingredient. Stripping as faeces collection technique was applied to obtain faecal material two times a day for 9 weeks. Apparent digestibilities of ingredients (ADIs) for crude protein (CP) were higher in SM (79.5 ± 5.1%) and SPC (75.2 ± 4.8%) than in CGM (59.2 ± 6.6%). Regarding ADIs of individual AAs, SM and SPC always showed higher values than CGM and PPC. ADIs for crude carbohydrates in CS (90.4 ± 2.2%), WS (88.8 ± 2.0%) and CGM (82.3 ± 3.9%) exhibited higher amounts than in SM (26.3 ± 1.0%). Evaluated apparent digestibilities indicate that in particular SM and SPC are good protein and CGM, WS and CS are promising carbohydrate sources to be included in diets for common carp. A strong correlation between ADI_CP and ADI_AA was determined. Stripping used for digestibility measurement in carp was found to be a viable method as conventional passive faeces collecting techniques such as sedimentation or sieving.  相似文献