feeding: fishes as predators feeding & predation cycles adaptations of predators
TRANSCRIPT
Feeding:Fishes as predators
Feeding & Predation cyclesAdaptations of predators
Predator – Prey arms race
• Co-evolution of predatory and escape mechanisms– Morphological adaptations– Behavioral adaptations– Ecological adaptations
“there is no perfect predatory nor perfect escape tactic”
Predation Cycle
• Search• Pursuit• Attack• Capture (Feeding Cycle)• Handling of Prey (Feeding
Cycle)
Feeding Cycle
• Biting• Sucking • Chewing• Swallowing
Search• Active Search (Use of locomotion while
employing senses to detect prey)
- Vision (Water column predators)• Herring & Anchovies • Tunas & Billfishes • Nocturnal Plankton feeders
Search• Active Search (Use of locomotion while
employing senses to detect prey)
- Vision (Water column predators)• Herring & Anchovies Tunas & Billfishes • Nocturnal Plankton feeders
– Olfaction• Elasmobranchs• Moray eels
Search• Active Search (Use of locomotion while
employing senses to detect prey)
- Vision (Water column predators)• Herring & Anchovies Tunas & Billfishes • Nocturnal Plankton feeders
– Olfaction• Elasmobranchs• Moray eels
– Hearing• Elasmobranchs (low frecuency sounds 20-300
Hz)
Search• Active Search (Use of locomotion while
employing senses to detect prey)
- Taste / Touch (benthic feeders)• Barbels (Catfishes, Goatfish, Croakers, etc…)• Modified fin rays (Sea robins, etc…)
Search• Active Search (Use of locomotion while
employing senses to detect prey)
- Taste / Touch (benthic feeders)• Barbels (Catfishes, Goatfish, Croakers, etc…)• Modified fin rays (Sea robins, etc…)
– Electroreception• Passive (Elasmobranchs)• Active (Elephantfish, Gimnotids, etc…)
Search• Active Search (Use of locomotion while
employing senses to detect prey)
- Taste / Touch (benthic feeders)• Barbels (Catfishes, Goatfish, Croakers, etc…)• Modified fin rays (Sea robins, etc…)
– Electroreception• Passive (Elasmobranchs)• Active (Elephantfish, Gimnotids, etc…)
Speculation Search (‘try and see’ chicken tactic…)
• usually occurs with attendant species
Search• Passive Search – Camouflage
Predators (No use of locomotion)
- Benthic Stalkers (Flounders, Scorpionfish, etc…)
•Vision•Electrorecepcion
Search• Passive Search – Camouflage
Predators (No use of locomotion)
- Benthic Stalkers (Flounders, Scorpionfish, etc…)
•Vision•Electrorecepcion
– Open Water Stalkers (gars, pike, trumpetfish)
•Vision
Pursuit• High Speed chases
- Specific to capture fast prey•Open Water – Speed
– Lamnid sharks, Tuna, Marlin…
•Benthic – Fast Braking and turning– Salmon, Striped Bass, Groupers…
Pursuit• High Speed Chases
- Specific to capture fast prey•Open Water – Speed
– Lamnid sharks, Tuna, Marlin…
•Benthic – Fast Braking and turning– Salmon, Striped Bass, Groupers…
• Fast Start Interception– Convergent evolution of body shape
– Pike, Barracuda, Gars, Needlefish…
Pursuit• High Speed chases
- Specific to capture fast prey•Open Water – Speed
– Lamnid sharks, Tuna, Marlin…•Benthic – Fast Braking and turning
– Salmon, Striped Bass, Groupers…
• Fast Start Performance– Convergent evolution of body shape
– Pike, Barracuda, Gars, Needlefish…
• Luring – Lophiiformes (fin rays), stargazers (buccal lures),
Haplochromis livingstoni (death feigning)...
Attack, Capture & Handling
• Directly related to jaw development
• Feeding Cycle (Biting, Sucking, Chewing, Swallowing)
• Mouth Positioning– Superior– Terminal– Inferior
Attack, Capture & Handling
• Directly related to jaw development
• Feeding Cycle (Biting, Sucking, Chewing, Swallowing)
• Mouth Positioning– Superior– Terminal– Inferior
• Suction Feeding (Jaw Protrusion)– Premaxillae, Maxillae & Lower Mandible– Preparation, Expansion, Compression, Recovery
• Pharyngeal Jaw– Handling / Chewing & Swallowing
Attack, Capture & Handling
• Overtake or Interception of prey• Suction of Prey
– Fastest movements if mobile prey (example: Frogfish expand mouth 14-fold in 6
milliseconds)– Slower movement if prey with limited
movement
Attack, Capture & Handling
• Overtake or Interception of prey• Suction of Prey
– Fastest movements if mobile prey (example: Frogfish expand mouth 14-fold in 6
milliseconds)– Slower movement if prey with limited
movement
• Filtering of prey– Swim with open mouths, filter planktonic prey
Filtering of Prey
CetorhinidaeBasking sharkCetorhinus maximus
Filtering of Prey
Attack, Capture & Handling
• Overtake or Interception of prey• Suction of Prey
– Fastest movements if mobile prey (example: Frogfish expand mouth 14-fold in 6
milliseconds)– Slower movement if prey with limited
movement
• Filtering of prey– Swim with open mouths, filter planktonic prey
• Prey Immobilization– Marlin, swordfish, sawfish (upper jaw extension)– Thresher Shark (tail)– Torpedo Rays (Electrical discharge)– Hammerhead Shark (head)