Sensory Perception

VisionOlfactionHearing & mechanoreceptionElectroreceptionMagnetoreception

Senses

Physical Quantity

Sense Organ

Sound Ears

Water flow Lateral line

Chemicals Taste Buds/Nose

Electricity Ampullae of Lorenzini

Magnetic Fields Nose ????

Light Eyes

Acoustico – Lateralis System

Hair sensory cells

•Equilibrium•Hearing•Mechanoreception

Sensory Hair Cells

Hearing in Fishes

• Fish have ears• Otoliths detect

particle motion• Swimbladder can

act as pressure transducer

What is Sound?

• Sound is a mechanical vibration that propagates through an elastic medium such as air or water.

• Sound travels as waves of oscillating particles accompanied by increases and decreases in the ambient pressure.

• Sound propagates along the axis of particle vibration.

Compression

Rarefaction

No Sound

Speaker

Ear Morphology

Fish hearing is generally low-frequency

Cyprinidae

American Shad Audiogram

Ultrasonic detection by american shad. Classical Conditioning: Example of cardiac response followed by electric shock

Ultrasonic sound detection by American Shad

Auditory Brain Response

Swimbladder of the toadfish, Opsanus sp.  Sonic muscles can be seen on the lateral walls.

BatrachoididaeOyster toadfishOpsanus tau

Sound Production

Ecology of Sound Production

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Sound produced by spawning aggregation of sciaenids

Lateral LineNeuromasts: groups of hair cell w/gelatinous cupule

Hydrodynamic Stimuli

• Water currents from flows (rheotaxis)

•Schooling/predator avoidance

•Active hydrodynamic imaging

•Passive hydrodynamic imaging

•Courtship

•Subsurface feeding

Flows produced by organisms

Lateral line shapes

Electroreception

ElasmobranchsTeleostsLow frecuency AC - DC

TeleostsHigh frequency AC

Electroreceptors

Ampullae de Lorenzini

Dogfish can detect a flounder buried 15 cm deep (1 mV/Km)

Electrical fishes

Electric Organ Discharge (EOD)• Modified muscle cells to create EOD

Brachyhypopomus spp. EOD

Magnetoreception

• Elasmobranchs– Hammerhead shark schools– Laboratory experiments with rays

• Teleosts– Magnetite found in Salmon and Tuna

Magnetoreception

Induced Electric Field•Currents in ocean flowing through earth’s magnetic field generate currents from <5 nV/cm to 500 nV/cm.

•Suspected that eels use these currents, but not clear if they are sensitive enough to electrical fields.

•Stingrays can sense fields as low as 5 nV.cm

At ambient magnetic field of 0.5 gauss, a swimming speed of 1 cm/s would produce a threshold stimulus of 5 nV/cm.This has yet to be proven.

Magnetite in Nose (Trout)a. Bacteria containing magnetite (not

from the trout).

b. Olfactory epithelium. Red dot with arrow is putative magnetite.

c. Bright field (left) and dark field (right) TEM of dot from b.

d. Energy dispersive analysis of x-rays from crystal. Shows presence of iron (Cu is from copper screen, Pb and U from TEM stains).

Walker, Diebel, Haugh, Pankhurst, Montgomery, & Green. 1997. Structure and function of the vertebrate magnetic sense. Nature. 390: 371-376.

Olfaction

Taste Buds

Vision

Photoreceptor cells

• Rods– Sensitive at low light levels– Present in all fishes

• Cones– Sensitive at high light intensity– Some elasmobranchs and most fishes

Red cones (600nm)Green cones (530nm)Blue cones (460nm)Ultraviolet cones (380nm)

Electromagnetic Wavelengths

Rod maximum absorption

Visual AcuityDetermined by eye aperture and photoreceptor density.

Acuity increases as size increases.