Fishes as prey: avoiding predation Avoidance of predators Adaptations of prey.

Fishes as prey: avoiding

predation

Avoidance of predatorsAdaptations of prey

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• Handling of Prey

Detection avoidance• Camouflage (avoidance of visual

predators)

Appearance of something unrecognizableDisappearance - become invisible

– Protective resemblance• Resemble background• Resemble inedible objects• Resemble predators

Detection avoidance• Camouflage (avoidance of visual

predators)

Appearance of something unrecognizableDisappearance - become invisible

– Protective resemblance• Resemble background• Resemble inedible objects• Resemble predators

– Disruptive coloration• Daytime• Nightime

Detection avoidance• Pelagic camouflage (avoidance of visual

predators)

– Countershading

Looking downwardsLooking upwards

Looking downwards

Detection avoidance• Pelagic camouflage (avoidance of visual

predators)

– Countershading

– Mirror sides

Mirror Sides

Detection avoidance• Pelagic camouflage (avoidance of visual

predators)

– Countershading

– Mirror sides

– Transparency

Detection avoidance• Pelagic camouflage (avoidance of visual

predators)

– Countershading

– Mirror sides

– Transparency

– Counterillumination (Bioluminescence)

Hatchetfish

Myctophid lanternfish

Detection avoidance• Pelagic camouflage (avoidance of visual

predators)

– Countershading

– Mirror sides

– Transparency

– Counterillumination (Bioluminescence)

• Olfaction avoidance (Avoidance of olfactory predators) – Mucous cocoon

Pursuit evasion• Morphological adaptations

– Stout and/or sharp spines– Poisonous spines– Toxic fishes

Usually with Aposematic Coloration (but not always)

Pursuit evasion• Morphological adaptations

– Stout and sharp spines– Poisonous spines– Toxic fishes

Usually with Aposemotic Coloration

• Behavioral adaptations– Use of bottom shelter– Use of holes and caves– Flying

Capture and Handling discouragement

• Body armours• Long dorsal and anal spines• Extra deep bodies• Inflation• Erection of sharp spines….