How to humanely dispatch lobster
Stun the lobster in either a saltwater ice slurry or by chilling in air:
Chilling in a saltwater ice slurry (at a ratio of 3:1 giving a consistency of wet cement) at a temperature around -1°C for at least 20 minutes or until there is no sign of movement. Larger lobster may need longer. This could be done in a sink or esky.
Chilling in air by placing the product into a freezer or chiller section of your fridge for at least 20 minutes (longer for larger lobster) or until there is no sign of movement.
Once the lobster is stunned and showing signs of insensibility, they should be mechanically killed immediately.
This is most easily achieved by splitting the lobster along the midline from head to tail with a large, sharp knife or inserting a knife deeply between the horns then turn the lobster over and cut to an inch deep from between the rear legs along to the mouth parts (spiking).