1Graduate School of Marine Science and Technology, and 2Department of Ocean Sciences, Faculty of Marine Science, Tokyo University of Marine Science and Technology, Minato, Tokyo 108-8477, Japan
The present study examined the growth of baleen plates with interpretation of the V-shape notch that appears on the baleen plate among Antarctic minke whales Balaenoptera bonaerensis. A total of 1,654 baleen plates including those from foetuses collected by the Japanese whale research program under special permit in the Antarctic (JARPA; 1,218 individuals) and commercial whaling (436 individuals) in Area IV were used for the present analysis, with relevant biological information. The total baleen plate length increased with body length and reached the maximum of 261.8 mm at larger than 7.9 m and 278.3 mm at larger than 8.4 m in males and females, respectively. The V-shape notch was found in all animals smaller than 5.5 m but not in the foetal stage, suggesting that the notch might form in the neonate. It seemed that the V-shape notch completely disappeared due to wear at the body length of around 6.4 m.