Parameters of growth and reproduction of white-beaked dolphins (Lagenorhynchus albirostris) from the North Sea

摘要

The white-beaked dolphin (Lagenorhynchus albirostris) is a robust, midsized dolphin with adult sizes up to 300 cm. It is endemic to the temperate and subarctic North Atlantic, where it usually inhabits shelf waters (Kinze et al. 1997, Kinze 2008). In the North Sea, the white-beaked dolphin is the second most common cetacean species after the harbor porpoise (Phocoena phocoena). Despite its prevalence, this species continues to receive limited scienti?c attention, and biological information, e.g., life history parameters, remains sparse. For dolphins off Newfoundland, Dong et al. (1996) reported physical maturity at 13–16 dentinal growth layer groups and at total lengths of 281 cm and 261 cm in males and females, respectively. Dong et al. (1996) also reported a sexually mature (pregnant) female of 174 cm, while the largest reported sexually immature female was a 246 cm individual from Dutch waters (Van Utrecht 1981). Several authors agree on birth lengths ranging from 110 cm to 120 cm (Tomilin 1967, Fraser 1974, Collet and Duguy 1981). Births seem to take place in the summer and young dolphins have been reported from June to September (Smeenk 1989, Berrow and Rogan 1997, Kinze et al. 1997).