Stunning
The process of ‘stunning’ means the animal becomes completely insensible to pain and distress. This insensibility should be instantaneous and must be maintained until death occurs.
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Currently, electrical stunning is the only humane method of stunning with research demonstrating a total loss of central nervous system activity and responsiveness to sensory stimulation [1-4]. When carried out using approved, specialist equipment and the correct, species-specific criteria is met, electrical stunning can deliver a swift (within one second), effective and humane stun to crabs, lobsters, crayfish and shrimps.
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However, other methods are practiced throughout the industry. These include chilling (below), the use of chemical anaesthetics, and CO2 gassing, all of which have the potential to cause significant welfare concerns.
[1] Roth, B., & Øines, S. (2010). Stunning and Killing of Edible Crabs (Cancer).
[2] Roth, B., & Grimsbø, E. (2016). Electrical Stunning of Edible Crabs (Cancer Pagurus): From Single Experiments to Commercial Practice.
[3] Fregin, T., & Bickmeyer, U. (2016). Electrophysiological Investigation of Different Methods of Anesthesia in Lobster and Crayfish.
[4] Weineck, K., Ray, A.J., Fleckenstein, L.J., Medley, M., Dzubuk, N., Piana, E., & Cooper, R.L. (2018). Physiological Changes as a Measure of Crustacean Welfare
under Different Standardized Stunning Techniques: Cooling and Electroshock.