Similar tagging studies in the 70s showed a distribution extending from the southern North Sea during summer to waters off Scotland during winter. In recent years, their distribution appears again as more northerly, but new tagging studies are needed to confirm this. It is probable that changes in occurrence of this species in Norwegian waters reflect combined effects of changes in both migration patterns and population size.
Dogfish form large schools, and once individuals are encountered large quantities may be captured. Males and females often form their own schools, as do large and small fish. Females give birth to a small number (7-11) of live offspring after a two-year gestation period. Capturing large schools with many pregnant females has a significant effect on future recruitment levels. Therefore, the spiny dogfish, like many other species of shark, are considered particularly vulnerable to overexploitation. Nevertheless, spiny dogfish in other areas appear to be able to rebuild after substantial over-fishing.