Contrasting structural complexity differentiate hunting strategy in an ambush apex predator

Area of Science:

• Ecology
• Aquatic predator behavior
• Behavioral ecology

Background:

• Structural complexity impacts prey dynamics but predator effects are less understood.
• Aquatic apex predators' behavioral responses to habitat structure warrant investigation.

Purpose of the Study:

• To investigate how contrasting structural complexity in lakes influences Northern pike foraging behavior.
• To compare Northern pike activity, space use, and prey utilization in low vs. high structural complexity environments.

Main Methods:

• Whole-lake acoustic telemetry tracked Northern pike (Esox lucius) movements.
• Stable isotope analysis assessed pike prey utilization.
• Survey fishing data characterized prey fish communities.

Main Results:

• Pike exhibited increased activity, space use, and growth in low structural complexity lakes.
• Behavioral differentiation and open-water presence were higher in low structural complexity lakes.
• Despite differing behaviors, both lakes showed reliance on littoral food sources.

Conclusions:

• Northern pike in high structural complexity lakes employed ambush predation.
• Pike in low structural complexity lakes shifted to active search behavior, potentially increasing prey encounters and growth.
• Habitat structural complexity significantly mediates apex predator foraging strategies and may impact prey communities.