METHOD AND DEVICE FOR STUNNING AND KILLING AQUATIC ANIMALS

Abstract: The invention relates to a method for stunning and killing an aquatic animal, comprising of having the animal accommodated in water, connecting a source of electric current to the water such that during a first period an electric current with a first current intensity is generated in the animal such that it is stunned, and conditioning the water such that, substantially immediately thereafter, the animal remains stunned during a second period.

Description: METHOD AND DEVICE FOR STUNNING AND KILLING AQUATIC ANIMALS The invention relates to a method for stunning and killing an aquatic animal . It relates very particularly, but not exclusively, to fish such as eel and other edible fish. Shellfish such as lobster, crab, prawns, molluscs and the like can also be stunned and killed in appropriate manner with the present invention. It is usual, and in accordance with the relevant legislation, for land animals, in particular animals for slaughter, to be killed in a manner such that no avoidable stress, pain or suffering occurs. For this purpose the animal is stunned and killed before the insensible state has worn off. The invention now has for its object to provide a method with which an aquatic animal can be killed in such a manner. This objective is achieved according to the invention with the method as characterized in claim 1. Owing to the relatively high electric current during the short first period there occurs immediate loss of consciousness and numbness in the aquatic animal. Brain activity is effectively deactivated. During the second period the heart activity becomes or remains minimized or disabled. At the same time the conditioning of the water prevents the animal recovering, wherein the muscles involved in respiration either cannot work or can only do so inadequately, so that there occurs a shortage of oxygen in the body of the animal, which will ultimately result in brain death, i.e. the death of the animal . A suitable embodiment of the method according to the invention is characterized in claim 2. The current intensity which is generated during the second, longer period and which can optionally be intermittent, prevents the animal from recovering. The measure of claim 3 is preferably applied. This measure is particularly important when the aquatic animal uses skin respiration. The skin respiration will effectively be deactivated by applying oxygen-free water, whereby the total duration of the operation can be limited. The water is advantageously made oxygen-free by introducing an oxygen-expelling gas therein. This oxygen-expelling gas is in further preference nitrogen. Nitrogen gas is a gas which is permitted for use in slaughtering animals, so that it is also a suitable type of gas in this case, which moreover results in a rapid expulsion of the oxygen from the water. According to another favourable embodiment of the method the animal is accommodated in cold water at a maximum of 0°C during at least the second period. The animal hereby remains in stunned state until death occurs . So as to make the method easily manageable the measure of claim 7 is preferably applied. Owing to the fixing the animal is held fast in a predetermined position, so that the current intensity can be precisely determined. The fixing preferably takes place by placing the animal in a channel-like element. It is hereby held fast in elongate position at a precisely determined location in the channel-like element. According to a further development of the method according to the invention the electric current is generated in the animal by generating an electrical field which is at least practically homogeneous . A number of animals simultaneously can hereby be stunned and then killed in one water volume. The required current intensity will be at least practically the same in each case depending on the position in the field. The magnitude of the first and second current intensity and the duration of the first and second period depend very greatly on the size and nature of the animal . It has thus been found that for eels a suitable duration of the first period is 1 second and a suitable first current intensity can be obtained at a voltage of about 200 volts. The second period is about 15 minutes here, and the voltage applied so as to reach the second current intensity can herein be 50 volts. Said voltages of 200 and 50 volts can be employed provided the respective current intensities lie in the order of respectively several hundreds and several tens of milliamperes which are carried through the individual animal . In the case of eels situated in the water, 6.2 milliampere per square centimetre of electrode area is preferably used as first current intensity and 1.4 milliampere is preferably used as second current intensity. These values can be employed provided the electrode area of one of the two electrodes is equal to the area of the bottom of the tank in which the eels are situated for the purpose of carrying out the stunning. The two electrodes are preferably equally large and of the same form. According to the invention the current intensities and time periods required for a species and size of animal for stunning and killing can suitably be determined experimentally. To this end a scientifically reliable number of animals are subjected to different current intensities and periods, wherein an electroencephalogram (EEG) and/or an electrocardiogram (ECG) of the animal is made, so that the effect can be determined. On the basis of the brain activity recorded using the EEG it is possible to establish whether the animal is unconscious and numb. The occurrence of fibrillation of the heart or complete ceasing of heart activity is determined on the basis of the ECG. If oxygen-free water is applied, the animals stunned and killed with the method and device according to the invention can be discharged with the water, whereafter new animals can be stunned and killed in fresh water.

Claims: CLAIMS 1. Method for stunning and killing an aquatic animal, comprising of having the animal accommodated in water, connecting a source of electric current to the water such that during a first period an electric current with a first current intensity is generated in the animal such that it is stunned, and conditioning the water such that, substantially immediately thereafter, the animal remains stunned during a second period. 2. Method as claimed in claim 1, wherein during the second period an electric current with a second current intensity is generated in the animal, wherein the second current intensity is lower than the first and the second period is longer than the first . 3. Method as claimed in claim 1 or 2, wherein the animal is accommodated in substantially oxygen-free water in at least the second period. 4. Method as claimed in claim 3, wherein the water is made substantially oxygen-free by introducing an oxygen-expelling gas therein. 5. Method as claimed in claim 4, wherein the gas is nitrogen. 6. Method as claimed in claim 1 or 2 , wherein the animal is accommodated in cold water at a maximum of 0°C during at least the second period. 7. Method as claimed in any of the foregoing claims, wherein the animal is fixed. 8. Method as claimed in claim 7, wherein the animal is fixed by being placed in a channel-like element. 9. Method as claimed in any of the foregoing claims, wherein the electric current is generated in the animal by generating an electrical field, which field is at least practically homogeneous. 10. Method as claimed in any of the foregoing claims, wherein the magnitude of the first and second current intensity and the duration of the first and second period are determined experimentally with an animal representative of a number of animals for stunning and killing. 11. Device for stunning and killing aquatic animals, comprising a water reservoir, an electric power source which is connected to the reservoir by electrodes, and switching means for generating electric current with adjustable current intensity in the water reservoir for adjustable periods via the electrodes. 12. Device as claimed in claim 11, further comprising gas feed means for feeding a gas into the water reservoir. 13. Device as claimed in claim 11 or 12, comprising at least one channel-like element for fixing at least one animal .

Inventors: AKSE LEIF JOERGEN, BYRNE HAZEL JOYCE FOSTER, HUIDOBRO PEREZ-VILLAMIL ALMUDE, KESTIN STEVEN CHARLES, KLOOSTERBOER RIKA JOHANNA, KUHLMANN HOLMER, LAMBOOIJ ELBERT, MUNKNER WERNER, NESVADBA PAUL, OEHLENSCHLAEGER JOERG, OTTERAA HAAKON, PIETERSE CORNELIS, ROBB DAVID HENRY FRANCIS, SCHELVIS-SMIT ADRIANA ANNA MAR, SORENSEN NILS KRISTIAN, TEJADA YABAR MARGARITA, VAN DE VIS JOHANNES WILHELMUS, VAN RIJSINGEN JOHANNES CORNELI, VANCOILLE CAROLINE GODELIEVE A, AKSE, LEIF, JOERGEN, BYRNE, HAZEL, JOYCE, FOSTER, HUIDOBRO PEREZ-VILLAMIL, ALMUDENA, KESTIN, STEVEN, CHARLES, KLOOSTERBOER, RIKA, JOHANNA, KUHLMANN, HOLMER, LAMBOOIJ, ELBERT, MUNKNER, WERNER, NESVADBA, PAUL, OEHLENSCHLAEGER, JOERG, OTTERAA, HAAKON, PIETERSE, CORNELIS, ROBB, DAVID, HENRY, FRANCIS, SCHELVIS-SMIT, ADRIANA, ANNA, MARIA, SORENSEN, NILS, KRISTIAN, TEJADA YABAR, MARGARITA, VAN DE VIS, JOHANNES, WILHELMUS, VAN RIJSINGEN, JOHANNES, CORNELIS, MARIA, VANCOILLE, CAROLINE, GODELIEVE, ANNA, MARIE
Applicants: NL I VOOR VISSERIJ ONDERZOEK R, NEDERLANDS INSTITUUT VOOR VISSERIJ ONDERZOEK (RIVO)
Application year: 2001
Main classification: A22B3
IPC codes: A22B3