FishPredation

Fish Predation

Common Methods

• Stalking
• Chasing
• Ambush
• Habituation
• Angling

Predation Model

• Energy vs. Cost
• Search → Encounter → Strike → Capture
• Factors Affecting Search:
  • For Predator: Hunger
  • For Prey: Camouflage
• Factors Affecting Encounter
  • For Predator: Swimming Speed, water clarity, illumination, schooling, detection mechanisms
  • For Prey: morphology, activity level, pigmentation, distribution
• Factors Affecting Strike
  • For Predator: alternative prey, location
  • For Prey: body size, sensory ability
• Factors Affecting Capture
  • For Predator: mouth gape, strike speed, handling
  • For Prey: escape capabilities, schooling, shelter seeking behavior

References: K.M. Bailey, JT. Duffy Anderson. 2001. Fish Predation and Mortality. Encyclopedia of Ocean Sciences (Second Edition). Pages 417-421.

Other Feeding Factors

• Size is the most important factor in determining predation rates
  • ex: There is a decreasing rate of predation with Jellyfish as fish larvae size increases.
• Predation happens at all sizes
  • Ex: microscopic organisms to large whales
• Highest rates of predation occur on juvenile fish.
• Predation is most common during life transitions.
  • Ex: after fish larvae hatch
• Most are active either during the day or at night, not 24 hours
• Diurnal or nocturnal feeding is normally fixed genetically
• Feeding rhythms
  • Tidal and lunar rhythms
  • Annual Rhythms

Importance of Predation

• Food web
  • trophic cascade/ top-down control
• Important Evolutionary Force