Studies of minke whale (Balaenoptera acutorostrata) ecology in the northeast Atlantic: Description of the 1993 scientific catch operations and preliminary results from stomach analyses and resource surveys

Ecological studies of the Northeast Atlantic minke whale\n(Balaenoptera acutorostrata), initiated in 1992, were continued in 1993.\nThe field work was carried out in spring (15 April-15 May),\nsummer (15 June-12 July) and autumn (25 August-20 September)\nusing four chartered small-type whaling vessels which operated\nin four selected subareas. To ensure random sampling of whales,\nstringent sampling procedures, where the vessels searched for\nwhales along predetermined transects within each subarea, was\napplied. Concurrent with the sampling of minke whales, estimates\nof potential prey abundance were carried out using accoustics and\ntrawls. A total of 69 whales were shot; 5, 35 and 29 in spring,\nsummer and autumn, respectively. Preliminary results from the\nstomach analyses indicate a diet where fish play a very prominent\nrole. Diet varied between both periods and areas. Gadoid fish\nspecies dominated the spring diet. In summer and autumn the diet\nin the northmost areas (Spitsbergen and Bear Island) was\nprimarily characterized by the presence of krill, to a much lesser extent by capelin. This is consistent with an increase in\nkrill and severe decrease in capelin availability in these areas\nin 1993. In the coastal areas of North Norway, herring is the\ndominant planktivorous fish, and was also the most important food\nitem for the whales both in summer and autumn. To some extent,\nhowever, the herring was accompanied by some gadoid species\nduring summer. Whale consumption of 0-group fish were observed\nto be rather limited. Along with material necessary for the study\nof condition and diet, sampling was also carried out for a number\nof other studies included in the framework of the Norwegian\nscientific catch program.