Norske pigghåmerkninger 1962

Abstract

The Norwegian taggings of the spur dog (Squalus achantias) for 1962 are considered. The main points are: 1. There still exists an extensive migration between the British Isles (summer) and Norway (winter) and vice versa; but the exceptions to this simple rule seem to multiply. 2. The spiny dogfish in the Norwegian fjords must be considered as strays from the main stock. North of the Sognefjord the experimental fishing has been negative. 3. The catches of spur dog in the Karmøy district in the autumn of 1962 consisted of fish from the main oceanic stock. 4. Calculations of the yearly mortality coefficient show a marked increase from 0.27 in 1959/60 to 0.38 in 1961/62. 5. There has been a nearly 50 % increase in the Norwegian catch of spiny dogfish from 1957/59 to 1960/62. 6. Some sort of effort statistics must be collected in order to evaluate whether these figures represent a danger to the stock.