Whether killing animals in an abattoir, on a farm or in the wild, humans must employ the quickest and least painful methods available, out of respect for the animals.
Professional sealers are required to be licensed, and to work rapidly and humanely in accordance with methods and regulations lain down by government authorities.
Two methods are generally used in killing seals: clubbing and shooting. Clubs are used to fracture the skull, and are well suited to the killing of young juveniles, which are more likely to stay still than adults. Clubbing also enables a seal to be killed without damaging the pelt.
A typical club is the hakapik, a multipurpose tool of Norwegian design. At one end it has a metal ferrule with a blunt projection on one side to strike the seal's skull, and a slightly bent spike on the other to secure the carcass and pull it, from the water if necessary.
Firearms, typically high-powered rifles in the hands of skilled marksmen, are generally used to kill adult seals, or in any situation where the hunt is conducted from boats.
Pierre-Yves Daoust et. al
Animal welfare and the harp seal hunt in Atlantic Canada, Can Vet J Vol. 43
The large majority of seals that were studied in the Canadian hunt, 98%, were killed in a humane manner, which compares very favourably with results of surveys done in abattoirs in North America.
Royal Commission on Seals and the Sealing Industry in Canada
of the more than 40 veterinarians, animal-welfare officers and biologists who have observed the hunt and assessed its humaneness, The Anti-sealing groups have emphasized the findings of only 2 veterinarians ? who concluded that not only was the hunt humane, but also that it could not be changed sufficiently to render it humane.