Southern Elephant Seals Replenish Their Lipid Reserves at Different Rates According to Foraging Habitat

Area of Science:

• Marine ecology
• Animal behavior
• Physiology

Background:

• Assessing energy balance in free-ranging marine predators is challenging.
• Understanding foraging efficiency is crucial for assessing predator responses to environmental changes.
• Southern elephant seals (SES) are key indicators of marine ecosystem health.

Purpose of the Study:

• To investigate how oceanographic habitat type influences foraging efficiency in female southern elephant seals.
• To determine the relationship between prey capture attempts, body condition, and habitat.

Main Methods:

• Ten post-breeding female southern elephant seals were tracked using bio-loggers.
• Data collected included prey catch attempts, body density, and activity levels.
• Foraging efficiency indices were compared across three distinct Southern Ocean habitats.

Main Results:

• Body density changes were linked to prey catch attempts, activity levels (with a 6-day lag), and habitat type.
• SES foraging north of the sub-Antarctic front showed higher rates of body density improvement.
• This occurred despite a lower daily prey catch attempt rate in this region.

Conclusions:

• Oceanographic habitat significantly influences southern elephant seal foraging efficiency and body condition.
• Foraging north of the sub-Antarctic front may offer access to more energy-rich or accessible prey.
• Understanding habitat-specific foraging is vital for comprehending marine ecosystem dynamics and predator-prey interactions.