Studies on the breeding habits of the minke whale (Balaenoptera acutorostrata) in the Yellow Sea

Minke whales caught in the Yellow Sea range from 4.16 m to 8.60 m in length with an average length of 6.93 m for the female and 6.14 m for the male. Sex ratio of the female is 74.3%. The pregnancy ratio of all sexually matured females is 65.8%. The minimum size of the pregnant whale observed is 6.60 m in length. Females having a body length of more than 7 m long are all sexually matured. According to the studies on the embryos obtained from the females caught in the northern Yellow Sea, there is only one breeding season each year. Mating mostly occurs from July through September, and the length of pregnancy is ten to eleven months with the peak of calving from May through July. Most females breed one calf each time, only two cases with twins. Sex ratio of female fetus is 56.6%, and the newly born calf measures 250–270 cm in body length. This paper was published in Chinese inOceanologia et Limnologia Sinica 13 (4): 338–345.