Sensory Perception
Vision
Olfaction
Hearing & mechanoreception
Electroreception
Magnetoreception
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
•Equilibrium
•Hearing
•Mechanoreception
Hair sensory cells
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
Speaker
particle vibration.
No Sound
Compression
Rarefaction
Ear Morphology
Fish hearing is generally lowfrequency
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
Sound Production
Swimbladder of the toadfish, Opsanus sp.
Sonic muscles can be seen on the lateral walls.
Batrachoididae
Oyster toadfish
Opsanus tau
Ecology of Sound Production
12000
10000
Frequency
8000
6000
4000
2000
0
18:00
19:00
20:00
21:00
22:00
23:00
Time
24:00
01:00
02:00
03:00
Sound produced by spawning aggregation of sciaenids
Lateral Line
Neuromasts: 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
Teleosts
High frequency AC
Elasmobranchs
Teleosts
Low frecuency AC - DC
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 Acuity
Determined by eye aperture and photoreceptor density.
Acuity increases as size increases.