feeding strategies in teleost fishes...2015/08/12 · feeding strategies in teleost fishes bioe 127...
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Feeding Strategies in Teleost FishesBIOE 127
Summer 2015
Vikram B. BaligaEcology & Evolutionary Biology
UC Santa Cruz
Environment
Characteristic Air Water
Density 1.21 kg m-3 1.024 x 103 kg m-3
Dynamic Viscosity 18.08 x 10 -6 Pa*s 1.07 x 10 -3 Pa*s
O2-Carrying Capacity 95% less than air
Thermal Conductivity 23 x air
Human Skull Fish Skull
44 bony elements at birth22 bones as an adult
Very little kinesis
# of bones varies widely among speciesTypically 30 to 60 bones
Highly kinetic
suction
ram
manipulation(biting)
Aquatic prey capture
Liem, 1980
Steven Day Tim Higham
Roi Holzmann Kristen Bishop
Lepomis macrochirus
DPIV Experiments
DPIV: Flow Velocity
Hydrodynamics of Suction Feeding(Day et al. 2005)
I. Flow = symmetrical
II. Velocity decreases drastically away from the mouth
III. Fluid speed is only significant within 1 mouth diameter
PolypterusHow Conserved?
Morphological Diversity
Seahorses
Mastacembalus
Anguilla
Catfishes
Cichlids
1) Inertial suction
2) Ram Feeding
3) Manipulation
Three Major Feeding Categories in the Aquatic Environment
NotMutuallyExclusive
Feeding Mechanisms
Suction
Body Ram
JawRam
Jaw Ram Necessitates Jaw Protrusion
Jaw Protrusion Extremes
Why might jaw protrusion have evolved?
1. Sneak up on your prey
2. Increase forces exerted on your prey
Research on Jaw Protrusion
• Accelerates the water around the prey
• Increase by up to 35% the total force exerted on attached, escaping and free-floating passive prey
• the strike.
Feeding Mechanisms
Suction
Body Ram
JawRam
Pure Ram
Pure Ram Strategy
Feeding Mechanisms
Suction
Body Ram
JawRam
Pure Ram
Biting
Extending the Strike
Ram Biters
Biting Diversity
Model Jaw Closing
3rd order lever
Speed Force
0 1
MA jaw –closing
Needlefish 0.04(Strongylura incisa)
Gar 0.051(Lepisosteus osseus)
Barracuda 0.27 (Sphyraena barracuda)
Queen trigger 0.43(Balistes vetula)
Summary
Functional Roles of Suction
1. Respiration
2. Prey Capture
3. Prey Transport
Gill Filaments 4,5
Prey Transport
Mouth -> -> -> Branchial Arches -> oesophagus
Sciaenops ocellatus -Red Drum
Grubich and Westneat. 2006. Journal of Anatomy 1: 79-92
Pharyngeal Musculature
Pharyngeal Jaw
Epibranchial
Pharyngobranchial
ceratobranchial
Pharyngeal Diversity
(a) Papilliform –plant shredding (b) Molariform- crushing snails
Cundall &Greene, 2000
Mehta & Burghardt, 2008; Mehta 2009
Snakes
Elongate Limb-reduced Forms
Teleost Phylogeny
Anguilliforms
Morays
• ~ 200 species
• Complete limb loss
• Coral reefs
Snakes Morays
• Elongate & limbless
• Can attain large sizes
• Obligate predators/ Consume large prey whole
• Affect local prey densities
How do morays consume large prey whole in the aquatic environment?
Moray Skull
What consequences do these features have on feeding behavior?
Can morays generate suction?
Pressure Data
• Muraena retifera
kPa = -1• Micropterus salmoides
kPa = -8
Mehta, unpubl data.
Biters use suction to transport prey
Inertial Feeding
Pharyngeal Jaws
Halichoeres bivittatus
Morphological & Functional Innovation
Thank you
UCLA
HARVARD LABORATORIES
Feeding Mechanisms
Suction
Body Ram
JawRam
Pure Ram
Biting