Evaluation of electrical stunning of sea bass (Dicentrarchus labrax) in seawater and killing by chilling: welfare aspects, product quality and possibilities for implementation

The objective was to assess neural, behavioural responses and product quality in farmed sea bass (Dicentrarchus labrax) upon electrical stunning in seawater. The electrical sinusoidal 50 Hz or pulse square wave alternating 133 Hz current induced a general epileptiform insult with a current of 3.3±0.2 or 3 A dm^?2, respectively, for 1 s head to tail in seawater. The total duration of the insult was 48±34 and 23±11 s. After stunning, the electro‐cardiogram revealed fibrillation and ceased or showed malfunction. Product quality was assessed in a group electrically stunned, followed by chilling in ice water and the controls were only chilled in ice water. The pH of the fillets was 0.1–0.2 lower (P<0.01) when stunned electrically at days 1, 2, 8 and 10 postmortem, where the colour did not differ. The percentage of sea bass effectively stunned using an electrical sinusoidal or pulse square wave current was above 85% within a confidence level of 95%. A combination of electrical stunning for 10 s, followed by chilling in seawater with ice flakes resulted in the death of all fish. The former method is recommended to be adapted for implementation in practice.     

Verzehrt der Hase Mäuse?

Ohne Zusammenfassung     

Wie lange dauert ein Hausbockbefall?

Ohne Zusammenfassung (Mit 1 Abbildung)     

Der Plenterwald, der gemischte Wald und die Stammformen der Laubh?lzer

Ohne Zusammenfassung     

Sediment management and the renewability of floodplain clay for structural ceramics

Background, aim, and scope  

The Netherlands has vast resources of clay that are exploited for the fabrication of structural ceramic products such as bricks and roof tiles. Most clay is extracted from the so-called embanked floodplains along the rivers Rhine and Meuse, areas that are flooded during high-discharge conditions. Riverside clay extraction is—at least in theory—compensated by deposition. Based on a sediment balance (deposition versus extraction), we explore the extent to which clay can be regarded as a renewable resource, with potential for sustainable use. Beyond that, we discuss the implications for river and sediment management, especially for the large engineering works that are to be undertaken to increase the discharge capacities of the Rhine and Meuse.