Context drives movement patterns in a mobile marine predator

Area of Science:

• Marine Biology
• Behavioral Ecology
• Conservation Science

Background:

• Intra-specific variability in movement is common but often overlooked, creating knowledge gaps on its drivers and ecological roles.
• Understanding individual differences in movement is crucial for predicting species' responses to environmental change.

Purpose of the Study:

• To investigate the drivers of variable movement behavior in bull sharks (Carcharhinus leucas) across their distribution.
• To test how resource availability and seasonal environmental changes interact to shape movement patterns.
• To assess potential alterations in movement under future climate change scenarios.

Main Methods:

• Acoustic telemetry of bull sharks and their teleost prey in southern Africa.
• Spatial analysis integrating animal movements with remote-sensing of environmental data.
• Context-focused approach examining movement in relation to life history requirements.

Main Results:

• Bull sharks exhibited varied movement strategies, including residency, small/large-scale movements, and 'leap-frog migrations'.
• High seasonal overlap with prey aggregations was observed in both central and peripheral populations.
• Movement patterns were context-dependent, influenced by environmental factors and prey dynamics.

Conclusions:

• Resource availability and seasonal environmental shifts interact to create predictable yet variable movement behaviors.
• Intra-specific movement variability in bull sharks suggests common underlying drivers across diverse taxa.
• Understanding these patterns is vital for predicting species' adaptability to changing environments.