Atlantic mackerel are caught in vast numbers by pelagic trawls. Their slaughter by asphyxiation on ice causes prolonged suffering. Humane alternatives are technically feasible.
Mackerel welfare in pelagic fisheries is almost entirely unaddressed. Fish caught in vast pelagic trawls are compressed in the codend, transferred to holds, and suffocate over extended periods. The scale - hundreds of millions of individual fish annually in UK waters alone - makes the welfare case for humane slaughter methods compelling. Electrical or percussive stunning followed by immersion in ice slurry can be applied to pelagic species and would dramatically reduce total fish suffering.