Finding suitable growth models for turbot (Scophthalmus maximus L.) in aquaculture 1 (length application)

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.     

Trace elements bioavailability to <Emphasis Type="Italic">Triticum aestivum</Emphasis> and <Emphasis Type="Italic">Dendrobaena veneta</Emphasis> in a multielement-contaminated agricultural soil amended with drinking water treatment residues

Purpose

The in situ stabilization of multielement-contaminated agricultural soils has limited effectiveness when using common single amendments. This study examined the use of drinking water treatment residues (WTR), based on (hydr)oxides of Fe, Al, or Mn, as a cost-effective solution to optimize the immobilization of metals (Cd, Pb, Zn) and As.

Materials and methods

Trace elements (TE) bioavailability was assessed under semi-controlled conditions in a pot study cultivating winter wheat (Triticum aestivum L. cv. Tiger) until maturity. An Fe-based WTR and a Mn-based WTR, applied at rates of 0.5 and 1% (m/m), were related to effects of lime marl (LM) application. Additionally, a bioassay with earthworms (Dendrobaena veneta) was conducted. Both bioassays were compared with measurements of NH₄NO₃-soluble, diffusive gradients in thin film (DGT)-available and soil solution TE concentrations, representing well-established surrogates for mimicking the bioavailable element fractions in soil.

Results and discussion

The application of the Fe-based WTR reduced As accumulation in vegetative wheat tissues (by up to 75%) and earthworms (by up to 41%), which corresponded with the findings from soil chemical analyses and improved plant growth and earthworm body weight. However, As concentrations in cereal grains were not affected, Cd or Pb accumulation by wheat was not mitigated, and Zn uptake was enhanced. By contrast, the Mn-based WTR effected the greatest reduction in Pb uptake, and lowered Cd transfer to wheat grain (by up to 25%). Neither the NH₄NO₃-soluble nor DGT-available concentrations matched with Cd and Zn accumulation in plants or earthworms, indicating interferences due to competition for binding sites according to the biotic ligand model.

Conclusions

The results obtained in this study suggest that a bioassay with key species prior to field application should be mandatory when designing in situ stabilization options. The application of WTR to an agricultural soil strongly affected TE bioavailability to plants and earthworms. Low application rates tended to improve biomass production of biota. Higher application rates involved risks (e.g., P fixation, TE inputs), and none of the amendments tested could immobilize all targeted elements.

     

Influence of a sodium formate/formic acid mixture on growth of juvenile common carp (Cyprinus carpio) fed different fishmeal replacement levels of detoxified Jatropha curcas kernel meal in practical,mixed diets

Intensification of cyprinid production has resulted in substantial increases in aquafeed demand for these species and a requirement for studies on new protein sources. Increased availability of presscakes from biodiesel crops may help to meet this requirement. The suitability of detoxified Jatropha curcas kernel meal (JKM), in combination with a dietary organic acid/salt blend (NDF), was tested in practical diets for juvenile common carp (Cyprinus carpio). Four treatment diets contained between 0% and 13.5% fishmeal with the fishmeal protein replaced by JKM (0%, 30%, 70%, and 100%). Four further diets of the same composition but including 0.5% NDF were also prepared, and all diets were fed to carps for eight weeks. There were no statistical differences in growth between diets containing JKM and the control. Furthermore, addition of dietary NDF significantly improved final weights, specific growth rates, feed conversion ratios, and protein efficiency ratios. Body composition analysis showed a significant impact of dietary JKM inclusion on increasing body lipid content. The addition of NDF showed a tendency to lower body lipid content (P = 0.11). JKM is a suitable protein source in diets for carp, and the inclusion of 0.5% of NDF proved to be beneficial.     

Testing a Soil Magnetometry Technique in a Highly Polluted Industrial Region in North-Eastern Germany

The paper presents the results of a study in the region Dübener Heide (Central Germany) testing the suitability of field measurements of magnetic susceptibility for the detection of historical fly-ash deposition. The measurements supported the verification of historically documented deposition zones along an emission gradient. Mean values, standard deviation, and coefficient of variation can be used to characterize the former deposition zones, although the study revealed several problems, which will be the subject of future work: (1) the volume susceptibility measurements used in the study do not allow the calculation of the actual fly-ash amount stored in the soil and thus must be calibrated with correction factors from laboratory measurements; and (2) measurements in regions with similar conditions but without fly-ash deposition are needed to obtain reference values for the natural range of magnetic susceptibility.     

Bioaccumulation of ivermectin from natural and artificial sediments in the benthic organism <Emphasis Type="Italic">Lumbriculus variegatus</Emphasis>

Purpose  

Although ivermectin is a widely used lipophilic parasiticide, data on its potential bioaccumulation in aquatic invertebrates are scarce. In this study, bioaccumulation patterns of radiolabeled ³H-ivermectin from sediments into tissues of the sediment-dwelling worm Lumbriculus variegatus were investigated and assessed.     

Quantitative estimates of freshwater fish stocking practices by recreational angling clubs in France

Although freshwater fish stocking is widely used by managers, quantitative assessments of stocking practices are lacking in many countries. The general objective of the present study was to determine the quantity and characteristics of fish stocking in metropolitan France. Using a survey-based approach, stocking practices for 2013 by recreational angling clubs in France were quantified, which represented the bulk of fish stocking undertaken in that year. Stocking was found to be practiced by 88.6% of angling clubs in France, representing, on average, 65% of their annual budget. Overall, 22 species were stocked, including 13 native and nine non-native species, with strong variations among species in terms of life stages and body sizes used for stocking. Using Bayesian modelling, a total biomass of 2.029 t, representing approximately 90 million fishes, was estimated to be stocked in France in 2013. In terms of biomass, the most widely stocked species were rainbow trout Oncorhynchus mykiss (Walbaum), brown trout Salmo trutta L., roach Rutilus rutilus (L.), common carp Cyprinus carpio L. and northern pike Esox lucius L. A stocking volume of approximately 60 fishes or 1.5 kg of fish biomass per angler per year seems commonplace in industrialised countries for which data are available.     

Protein adsorption on nano-scaled, rippled TiO2 and Si surfaces

We synthesized nano-scaled periodic ripple patterns on silicon and titanium dioxide (TiO(2)) surfaces by xenon ion irradiation, and performed adsorption experiments with human plasma fibrinogen (HPF) on such surfaces as a function of the ripple wavelength. Atomic force microscopy showed the adsorption of HPF in mostly globular conformation on crystalline and amorphous flat Si surfaces as well as on nano-structured Si with long ripple wavelengths. For short ripple wavelengths the proteins seem to adsorb in a stretched formation and align across or along the ripples. In contrast to that, the proteins adsorb in a globular assembly on flat and long-wavelength rippled TiO(2), but no adsorbed proteins could be observed on TiO(2) with short ripple wavelengths due to a decrease of the adsorption energy caused by surface curvature. Consequently, the adsorption behavior of HPF can be tuned on biomedically interesting materials by introducing a nano-sized morphology while not modifying the stoichiometry/chemistry.     

The state and consumer confidence in eco-labeling: organic labeling in Denmark,Sweden, The United Kingdom and The United States

Trustworthy eco-labels provide consumers with valuable information on environmentally friendly products and thus promote green consumerism. But what makes an eco-label trustworthy and what can government do to increase consumer confidence? The scant existing literature indicates that low governmental involvement increases confidence. This suggests that government should just provide the basic legal framework for eco-labeling and leave the rest to non-governmental organizations. However, the empirical underpinning of this conclusion is insufficient. This paper analyses consumer confidence in different organic food labeling regimes with varying degrees of governmental involvement. Using unique and detailed survey data from the US, United Kingdom, Denmark, and Sweden, the analysis shows that confidence is highest in countries with substantial state involvement. This suggests that governments can increase green consumerism through active and substantial involvement in eco-labeling.     

Evaluation of an indirect oscillometric blood pressure monitor in normotensive and hypotensive anesthetized dogs

Objective – To determine the accuracy and precision of an oscillometric noninvasive blood pressure device as a predictor of invasive direct blood pressure in healthy anesthetized hypotensive and normotensive dogs. Design – Prospective observational study. Setting – University teaching hospital. Animals – Eight crossbred adult dogs. Interventions – Anesthesia was induced with propofol and maintained with isoflurane. A catheter was placed in the dorsal pedal artery to record systolic, mean, and diastolic arterial blood pressures (aSAP, aMAP, and aDAP, respectively). The noninvasive blood pressure device cuff was placed around the contralateral front limb to record noninvasive systolic, mean, and diastolic blood pressure (nSAP, nMAP, and nDAP). Two states of blood pressure (BP) were studied: baseline state was established by keeping end‐tidal isoflurane concentration at 1.2±0.1%. The hypotensive state was achieved by maintaining the same isoflurane concentration while withdrawing approximately 40% of the animal's blood volume until aMAP was stable at approximately 40 mm Hg. At the end of the study, blood was returned to the animal and it was allowed to recover from anesthesia. Measurements and Main Results – Agreement between the direct and indirect BP measurements was determined by the Bland‐Altman method. The SAP and MAP but not DAP bias varied significantly between each BP state. Normotensive absolute biases (mean [SD]) for SAP, MAP, and DAP were ?14.7 mm Hg (15.5 mm Hg), ?16.4 mm Hg (12.1 mm Hg), and ?14.1 mm Hg (15.8 mm Hg), respectively. Absolute biases during the hypotensive state for SAP, MAP, and DAP were ?32 mm Hg (22.6 mm Hg), ?24.2 mm Hg (19.5 mm Hg), and ?16.8 mm Hg (17.2 mm Hg), respectively. Conclusion – The oscillometric device was not reliably predictive of intra‐arterial BP during hypotension associated with acute hemorrhage.