As shrimp welfare science advances and their sentience becomes increasingly accepted, the question of humane pre-slaughter methods becomes urgent. Cold stunning by ice immersion is widely used and claimed as humane — but research on its effectiveness as a welfare measure is contested.
The welfare effectiveness of cold stunning depends on whether low temperatures suppress conscious awareness or merely motor function. Research suggests that some shrimp species retain neural activity at temperatures used in commercial cold stunning, meaning they may experience the processing procedures while immobilised. This is analogous to curare paralysis in vertebrates — movement is prevented but consciousness and pain perception may be retained. Electrical pre-stunning achieves more rapid and complete neural suppression, but equipment costs and feasibility at commercial scale remain barriers. Given scientific uncertainty, the precautionary principle supports developing electrical stunning alternatives for shrimp as a welfare improvement measure.