Reproductive Energetics and Female Attendance Patterns of Cape Fur Seals (Arctocephalus pusillus pusillus) During Early Lactation

TLDR: A significant increase in length of time at sea was observed during the first 4 mo of lactation and milk ingestion and field metabolic rates established a baseline for the energetics of 1 mo old pups.

Abstract: The Cape fur seal (Arctocephalus pusillus pusillus) is a common pinniped species along the southern African coastline. While much information is available about this species, little is known concerning its reproductive energetics. With radio telemetry, we monitored attendance patterns for 1 to 4 mo from 1996–1999. Attendance of 29 nursing females averaged 1.86 ± 0.77 d on shore and 5.23 ± 2.87 d at sea. Mean cycle time was 7.09 ± 4.33 d, of which 29.6% was spent on shore and 70.4% at sea. A significant increase in length of time at sea was observed during the first 4 mo of lactation. Reproductive condition was quantified using measures of body condition and milk composition. Milk ingestion and field metabolic rates established a baseline for the energetics of 1 mo old pups. Body composition averaged 11.05 ± 2.31% lipid and 19.15 ± 2.60% protein. Milk from 17 individuals was composed of 58.07 ± 6.79% water, 2.02 ± 0.58% ash, 10.76 ± 1.23% protein and 23.16 ± 8.24% lipid. Milk energy content averag...