Undersøkelser av akkar (Todarodes sagittatus) (Lamarck), tatt ved kysten av Norge, i den nordlige Nordsjø og syd for Færøyene i oktober 1978 - mai 1979

• Main Author: Wiborg, Kristian Fredrik
• Format: Report
• Language: Norwegian Bokmål
• Published: Havforskningsinstituttet 1979
• Subjects: akkar; squid; Lamarck; Norway; Faroes; Færøyene; North Norway; Northern Norway
• Online Access: http://hdl.handle.net/11250/113173

Materials for investigation were collected during research cruises in October-November in the coastal areas of western and northern Norway, and in December 1978 - May 1979 in the northern North Sea and south of the Faroes (Table l), During the autumn of 1978 T.sagittatus mainly migrated to the Andfjord area in North Norway where a fishery took place in October-December. Off northern Norway the mean mantle length of the different samples was 33-34 cm, off western Norway 27-30 cm. In the northern North Sea most squid taken during December-April measured 18-28 cm, a few 13-17 cm and 30-36 cm. Those taken in May had a mean length of 30 cm. The total edible weight was on an average 74% of the total weight (mantle 50%, arms and tentacles, 24%) . Off northern Norway the liver weight constituted 12,6% (6-16) of the total weight, off western Norway 10% (4-13), south of the Faroes, 7.1% (3-13) . Males are easily distinguished macroscopically by the condition of the skin, becoming ragged and slimy very soon after capture, while the females keep their skin firm and smooth. Off northern Norway males constituted 8-25% of the stock, off western Norway 4%. In the North Sea nearly as many males as females were caught in December-April (10 male, 13 female) in May at the Faroes, 30% were males. It is suggested that males are less willing to take the hooks than the females. All females taken were immature. In two males, mantle lengths 31 cm and 36.5 cm, caught in the North Sea in December, the gonads weighed 7.2 and 13.0 g respectively, i.e. 2.0 and 1.0% of the total weight. At the Faroes the gonads of the males were more or less in an advanced stage of development, constituting 0.5-2.0% of the total weight. Food items in the stomachs were dominated by fish, off northern Norway saithe, herring and redfish, at the Faroes blue whiting. Euphausiids ranged second, squid third. It is suggested that the high percentage of squid recorded earlier (WIBORG 1972, 1978) may partly be an artifact, as arms and tentacles are torn off during the fishery and then eaten by the squid. Following LIPINSKY (1978), ageing of squid was attempted in studying the statholiths under a microscope after grinding. Rings, supposed to be daily growth rings, were seen, and countings seem to confirm the earlier hypothesis (WIBORG 1972) of two populations of T. sagittatus, spawning during December-January and May-July respectively. Location of squid with echo sounders and fishing experiments with Japanese jigging machines were successful. T. sagittatus is now readily accepted for human consumption.