Research Document - 2012/134

Force needed to effectively fracture skulls of grey and harp seal beaters using a hakapik

By L.D. Roy, E. Jenson, and M. Hiltz

Abstract

The impact force needed to fracture the skull of 6 grey seal young of the year, 9 harp seal young of the year and 3 adult harp seals was examined. The force required to crush adult skulls was greater than that required to crush the skulls of young of the year. Mean velocity resulting in effective blows (damage rating 3 and 4) was 21.44 m/s (n=4) for harp seal young of the year and 27.04 m/s (n=3) for grey seal young of the year. The effective blow velocity was lower for harp seal than grey seal beaters, but differences were not significant due to small sample sizes. Based on a 17.68 m/s velocity that result in an effective blow (damage rating of 3) to a harp seal beater head, effective blows can be delivered by sealers to harp seal beaters on a sustained all day basis. Based on a 24.60 m/s velocity that result in an effective blow (damage rating of 3) to a grey seal beater head, it is less likely that effective blows can be delivered on a sustained all day basis. These recommendations need to be taken with caution as sample sizes were low and we did not test the sustainability of produced velocities.

Complete document (PDF, 628 KB)

Accessibility Notice

This document is available in PDF format. If the document is not accessible to you, please contact the Secretariat to obtain another appropriate format, such as regular print, large print, Braille or audio version.