from a site (frequently asked questions) of the Canadian Fisheries and Aquaculture Management:

6. What types of weapons are used to kill seals?

Sealers use a variety of tools to hunt seals. Ninety per cent of sealers on the ice floes on the Front (in the waters east of Newfoundland), where the majority of the hunt occurs, use firearms. Sealers in the Magdelen Islands (Gulf of St. Lawrence) and on Quebec's Lower North Shore traditionally use clubs or hakapiks. A hakapik is an efficient tool designed to kill the animal quickly and humanely. Marine Mammal Regulations state that sealers must strike the seal on the skull until it's crushed, and administer a blinking eye reflex test or manually check the skull.

Together with heric's post that point should be clear now.

Wolfgang