Marine mammals rely on blubber mainly for energy storage, buoyancy, and streamlining. Mysticetes are born with a relatively thin fat layer that grows rapidly during nursing. However, little information on blubber deposition patterns is available for baleen whale calves. We measured blubber thickness at nine body locations in 350 southern right whale (Eubalaena australis) newborn to 4–6-month-old calves that died on the Península Valdés (Argentina) calving ground from 2003 to 2019, to document changes in blubber thickness with growth. Additionally, we looked for differences in blubber thickness and lipid content of the outer/superficial blubber in calves that died in years with high (2003, 2005, 2007–2013) and low calf mortality (2004, 2006, 2014–2019) to test whether the former were suffering from gross nutritional stress. Blubber thickness increased at all body locations with calf length. Along the cranio-caudal axis, blubber increased in the dorsal and ventral planes, but decreased laterally towards the peduncle, possibly to improve streamlining. We found no difference in blubber thickness and lipid content between high and low mortality years, suggesting that individuals were not undernourished. This is the first study to describe progressive increases in calf blubber during growth and contributes knowledge to right whale health and ontogeny.

中文翻译：

---

生长中的南露脊鲸幼崽（Eubalaena australis）的鲸脂脂肪沉积模式和身体状况评估

海洋哺乳动物主要依靠鲸脂来储存能量、提供浮力和流线型。Mysticetes 出生时脂肪层相对较薄，在哺乳期间会迅速增长。然而，关于须鲸幼崽的鲸脂沉积模式的信息很少。我们测量了 350 头南露脊鲸 ( Eubalaena australis)九个身体部位的鲸脂厚度) 2003 年至 2019 年在 Península Valdés（阿根廷）产犊场死亡的 4-6 个月大的新生小牛，以记录脂肪厚度随生长的变化。此外，我们寻找在高死亡率（2003、2005、2007-2013）和低死亡率（2004、2006、2014-2019）年份死亡的小牛的脂肪厚度和脂肪含量的差异进行测试前者是否患有严重的营养压力。随着小腿长度的增加，所有身体部位的脂肪厚度都增加了。沿着颅尾轴，鲸脂在背侧和腹侧平面增加，但朝向花梗横向减少，可能是为了改善流线型。我们发现高死亡率和低死亡率年份之间的脂肪厚度和脂质含量没有差异，这表明个体并未营养不良。