The effect of electric pulse stimulation to juvenile cod and cod of commercial landing size

The first pilot study on the effects of electric pulse stimulation on larger cod carried out in 2008 was based on a single nominal setting of the Verburg-Holland UK153 pulse system with the intention to determine the range of pulse characteristics with which injuries to the fish occurred. This study was designed to obtain a more detailed view on the effects of the pulse characteristics and to investigate if a specific pulse parameter has a key role in the effects. Lower pulse amplitudes with longer pulse width and higher frequency could induce different effects than pulses with higher amplitudes, shorter pulse width and lower frequency. In this way the effects can be related to a specific pulse parameter and its threshold value. Another aim of major importance is that this research also carried out on the electrically exposed fish that would normally escape through the cod-end meshes with unknown longer term effects. This was already recommended after the first experiment in 2008

Surface modification of ZrO₂ - Y₂O₃ ss by ion implantation

With 56Fe+ implantations in oxygen ion conducting solid solutions of 0.86ZrO2-0.14YO1.5 [ZY14] electronic conductivity is introduced in a surface layer of less than 70 nm. The theoretically expected Gaussian distributions of Fe ions as calculated by computer simulation are compared with results of analyses by AES and RBS. Mean projected ranges (Rp) agree but remarkable differences in peakheight and halfwidth are found. Surface concentrations up to 6∗1021 ZY Fe/cm3 have been achieved using mediate doses of 2–4∗1016 Fe/cm2 and energies ranging from 15–110 KeV. Concurrent sputtering during high dose implantations (8–40∗1016 Fe/cm2, 15 and 110 KeV) causes a peakshift towards the solid-gas surface. With these high doses high concentrations up to 24∗1021 Fe/cm3 were obtained. The implanted profile shapes remain stable under heat treatments up to 900°C. Higher temperatures cause a decrease in topconcentration and broadening of the distribution. After annealing during 25 hrs. at 1500°C all implanted iron was dissolved in the ZY matrix and no precipitates were formed as indicated by XRD

The effect of pulse stimulation on marine biota - Research in relation to ICES advice - Progress report on the effects on benthic invertebrates

In response to ecosystem related concerns about bottom trawling and particularly beam trawling that were raised by various scientists in the last decades of the previous century. Many studies were done in the 1970s and 1980s, but in spite of promising results commercial uptake was lacking. The development of pulse trawling was again taken up in the 1990s by a private company (Verburg:Holland Ltd.) in The Netherlands. Meanwhile questions about ecosystem effects of introducing pulse beam trawling in the Dutch flatfish fishery were raised by the European Scientific, Technical and Economic Committee for Fisheries (STECF) and the Inter: national Council for the Exploration of the Sea (ICES) and discussed at the meeting of the ICES Working Group on Fishing Technology and Fish Behaviour (WGFTFB) in 2006. These questions led to field strength measurements in situ onboard the commercial beam trawler, and research on the effects of pulse stimulation on cod (Gadus morhua L.), and elasmobranch fish

Electronic properties of ion-implanted yttria-stabilized zirconia

Ion implantation of iron and titanium has been applied to modify the surface properties of polycrystalline yttria-stabilized zirconia ((ZrO2)0.87(YO1.5)0.13 (YSZ)) discs in an attempt to prepare surfaces with a mixed conductivity and by this an enhanced surface oxygen exchange kinetics. Surface-sensitive spectroscopic techniques were applied to investigate the implanted layers as a function of different pretreatments such as oxidation, reduction and annealing. Depth profiles were recorded by Rutherford Backscattering Spectroscopy (RBS) and X-ray Photoelectron Spectroscopy (XPS) in combination with sputtering. Ion Scattering Spectroscopy (ISS) and XPS were used to investigate the surface composition and valency of implanted ions. Electronic properties like the band gap, the work function and the energy difference between the Fermi level and valence band edge (EF-EV) were obtained from Ultraviolet Photoelectron Spectroscopy (UPS) and Electron Energy Loss Spectroscopy (EELS). Overlayers of Fe2O3 or TiO2 are formed during oxidation of as-implanted samples. The Fe- and Ti-oxides could be reduced in hydrogen to the oxidation states Fe2+, Fe0 or Ti3+. Annealing of the samples leads to decreased surface concentrations of the implanted ions due to in-diffusion. At the surface of the annealed iron-implanted samples, Fe2+ and metallic Fe could be generated after further reduction whereas at the surface of the annealed Ti-implanted samples only Ti4+ was detectable.\u

Use of high resolution sonar for near-turbine fish observations (DIDSON) - We@Sea 2007-002

In this study we investigate small scale distribution of pelagic fish within a windfarm by means of a high resolution sonar (DIDSON, Dual frequency IDentification SONar; Soundmetrics). In addition we assess the bias of small scale variations induced by the effects of wind turbines (monopiles) on distribution of the pelagic fish community in the hydro acoustic surveys carried out on the OWEZ Near Shore Wind farm (NSW)

Gedrag van schieraal rond een viswering met stroboscooplampen bij gemaal IJmuiden. DIDSON metingen

Om de sterfte van uittrekkende schieraal in het gemaal van IJmuiden in het Noordzeekanaal te verminderen heeft Rijkswaterstaat Noord-Holland een meerjarig en multidisciplinair onderzoek uitgezet om effectieve maatregelen te kunnen nemen en te testen op effectiviteit

Onderzoek naar de effecten van de aanleg van een 20 m-paalanker voor Mosselzaad Invang Installaties (MZI's) op zeezoogdieren

Mosselzaad Invanginstallaties (MZI’s) in de Waddenzee en Oosterschelde worden opgehangen aan 20 m-paalankers, die met een trilhamer in de zeebodem worden gedreven. In het kader van het beheersplan voor de MZI-vismethode werden de effecten van de aanleg van een paalanker op zeehond en bruinvis bepaald. Een 20 m-paalanker werd met een trilhamer onder bedrijfsmatige condities in de zeebodem gedreven, terwijl het onder- en bovenwater ontwikkelde geluid op afstanden van 25 tot 1600 m van de trilhamer werd gemeten. De metingen vonden plaats op korte afstand van de MZI-locatie Vogelzand in de Waddenzee. Deze locatie werd gekozen vanwege de harde bodem, zodat het gemeten geluid onder de zwaarst mogelijke conditie is bepaald

High Floral Tannin White Clover Reduces Rumen Ammonia Concentrations in Dairy Cows

White clover produces high quality forage for ruminant production, but it results in high rumen ammonia concentrations, indicating extensive protein degradation. The excess ammonia is absorbed through the rumen and excreted as urea in urine, at a cost to the animal and the environment. Condensed tannins (CT) contained in some forages reduce proteolysis in the rumen, which can lead to increased amino acid absorption and therefore improved animal performance. White clover produces CT in its flower heads, but concentrations are normally too low to benefit animals. This paper reports on comparisons of rumen ammonia concentrations in dairy cows grazing HT (high tannin) white clover (an experimental line of white clover with increased flowering) or Grasslands Huia white clover

Condensed Tannin Concentration and Herbage Accumulation of a White Clover Bred for Increased Floral Condensed Tannin

White clover is a high quality feed for ruminants, however, its high protein content results in excessive urea excretion in urine and can cause bloat, reducing its potential value for animal production. The condensed tannins (CT) in some forages can reduce these problems, but plants may have poor agronomic performance. White clover produces CT in its flower heads, but herbage CT concentrations are normally too low to benefit animals. This paper reports CT concentrations and herbage accumulation over 2 years of an experimental line of white clover (HT) selected for increased flowering and floral CT concentrations

Ontwikkeling Automatisch Glasaaltelapparaat en Hevel

De glasaalintrek is sterk achteruitgegaan. Dit heeft tot gevolg dat zeer lage aantallen glasalen gevangen worden met het kruisnet gedurende de jaarlijks terugkerende Wageningen IMARES glasaalmonitoring. Deze ontwikkeling creëert een aantal monitoringsproblemen: 1. De schattingsvariatie neemt toe door de lage vangsten en de vele 0-waarnemingen. Hierdoor is het moeilijk te bepalen of de glasaalintrek de laatste jaren verder afneemt, toeneemt, of gelijk blijft. 2. De vele 0-vangsten gaan ten koste van de motivatie van medewerkers Als oplossing is een ontwikkelingsproject gestart rond een apparaat dat glasaal volautomatisch herkent en telt als onderdeel van een hevelsysteem