ESTIMATING MEAN BODY MASSES OF MARINE MAMMALS FROM MAXIMUM BODY LENGTHS

Generalized survival models were applied to growth curves published fo r 17 species of cetaceans (5 mysticetes, 12 odontocetes) and 13 specie s of pinnipeds (1 odobenid, 4 otariids, 8 phocids). The mean mass of a ll individuals in the population was calculated and plotted against th e maximum body length reported for each species. The data showed stron g linearity (on logarithmic scales), with three distinct clusters of p oints corresponding to the mysticetes (baleen whales), odontocetes (to othed whales), and pinnipeds (seals, sea lions, and walruses). Excepti ons to this pattern were the sperm whales, which appeared to be more c losely related to the mysticetes than to the odontocetes. Regression e quations were applied to the maximum lengths reported for 76 species o f marine mammals without published growth curves. Estimates of mean bo dy mass were thus derived for 106 living species of marine mammals.