In ETHIQUAL, the development of non-invasive ‘smart-tags’ shows very promising results and may be an important tool to monitor ethical qualities in free swimming farmed fish. Specifically, we have evaluated the use of respiration, brain activity (EEG), electromyogram (EMG), and blood-gas analyses (pulsoximetry) as candidate parameters, in a series of hard-wire laboratory experiments. This has led to a new collaboration with a commercial telemetry-company for the development of an acoustic smart-tag prototype that measure respiration in free swimming fish. The baseline studies of carp, having been initiated in the first reporting period, will represent new knowledge to general recommendation regarding ethical qualities in fish, both regarding husbandry and pre-slaughter conditions. The development of knowledge of transportation and pre-slaughter methods for farmed fish are promising, and will have direct beneficial effects for the farming industry. Resolution of rigor mortis is of interest, as it results in tender flesh, which is an essential product quality attribute. With regard to flesh quality of turbot, a procedure to achieve resolution of rigor in turbot is needed to study the effects of pre-slaughter conditions on fish flesh properties. It appeared that an enhanced resolution of rigor mortis could be achieved by applying a pulsed 50 Hz a.c. after gutting. Assessment of electrical stunning of carp revealed that an immediate loss of consciousness could be provoked by applying 163 ± 1 V and 240 ± 30 mA on the head of the fish.
