Fish as Acoustic Targets

LO: Rank the relative importance of biological and physical factors influencing target strengths of swimbladdered fish. Water as an Acoustic Medium

800x more dense than air Minimal effects of gravity Friction – absorption α Incompressible – vibrations carry better in water than in air (c = 1500 vs 333 m/s) Fish as Acoustic Receptors Acoustico-lateralis System - hearing, equilibrium - inner ear, swimbladder, lateral line

Lateral line: detects turbulence (near field) through neuromasts Inner ear & swimbladder: detects particle acceleration (far field) Lateral Line

Lateral Line

Neuromasts

- does not detect sound - detects water movements relative to body Fish Inner Ear

Inner Ear Cod Head Radiograph Inner Ear

Otolith Organ Saccular Macula in cod Otolith Organs

Otolith organs function as accelerometers, not sensitive to pressure

Inner ear sensitive to infrasound (< 20 Hz) Fish as Acoustic Scatterers

Rayleigh Resonant Geometric

L/λ << 1 L/λ ≈ 0.1 L/λ >> 1 point source organ pipe wall Acoustic Biological Perspective

Morphology anatomy material properties Ontogeny growth (body, scattering organs) sexual maturity Physiology feeding gonad production group – shoaling and schooling, Behavior avoidance individual – orientation (tilt, roll, direction), avoidance Morphological Categories

With Gas Inclusions - physonectid siphonophores: gas-filled pneumataphore - physostomous and physoclistous fish: swimbladder (open) (closed)

Without Gas Inclusions - phytoplankton - zooplankton - fish without swimbladders or wax/ester swimbladders Fish Morphology

Anatomy - shape, scales, skin, fins, skeleton, muscles, swimbladder

Walleye pollock (Gadus chalcogrammus) Morphological Variability

Intraspecific: Brook Trout Interspecific: Lavnun Swimbladder Factoids

- 4-5% of fish volume (Sand and Hawkins 1973; Harden Jones and Scholes 1985) - physostomes obey Boyle’s law up to 10 atmospheres (Ona 1990; Mukai and Iida 1999) - swimbladder wall can reversibly expand within 50% pressure reduction but bursts between 60-70% pressure reduction (Tytler and Blaxter 1973) - Foote (1980) > 90% of backscatter from swimbladder Swimbladder Variability

Pollack (Pollachius pollachius)

sagittal cross-section

Foote 1985 Contribution of Swimbladder to TS

38 kHz 120 kHz % Contribution

Foote 1980 Morphological Backscatter Variability

Acker 1977 Tilt, Roll, and Frequency-Dependence

12 kHz 38 kHz 70 kHz

120 kHz 200 kHz Measuring Body-Part Backscatter

Yellow perch

220 kHz Sun et al. 1985 Fish Morphology: Densities

100 YoY Juv Adult 80

60

40

Relative Density Relative 20

0 Otolith Skull Vertebrae Swimbladder Dorsal Posterior Caudal Sample Locations Material Properties Material Properties - sound reflection influenced by density (g) and sound speed (h) contrasts g: density ratio relative h: sound speed ratio to water (unitless) relative to water (unitless)

ρ fb c fb g fb = h fb = ρw cw

ρ: density (units kg m-3) c: speed of sound (units ms-1) TS Variation: swimbladder

12 kHz 38 kHz

) 0.260 0.260 -4 -4·10- 4

h -4·10 (

t 0.255 0.255 s -4 -4

a -3·10 -3·10 r

t 0.250 0.250 n

o -2·10- 4 -2·10- 4 C

0.245 0.245 d

e -4 -4 e 0.240 -1·10 0.240 -1·10 p

S

d 0.235 0 0.235 0 n

u

o 0.230 1·10- 4 0.230 1·10- 4 S 0.225 0.225 2·10- 4 2·10- 4 0.220 0.220 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 120 kHz 200 kHz 0.260 0.260 -4 -4 ) -4·10 -4·10 h

(

0.255 0.255 t -4 -4 s -3·10 -3·10

a r 0.250 0.250 t

n -4 -4 o -2·10 -2·10 0.245 0.245 C

d -4 -4 e 0.240 -1·10 0.240 -1·10 e

p

S

0.235 0 0.235 0 d

n

u 0.230 -4 0.230 -4 o 1·10 1·10 S 0.225 0.225 2·10- 4 2·10- 4 0.220 0.220 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 Density Contrast (g) Density Contrast (g) TS Variation: body

12 kHz 38 kHz 1.090 1.090

) h

(

t 1.080 1.080 s a r

t 1.070 1.070 n o C

1.060 1.060 d e

e 1.050 1.050 p

S

d 1.040 1.040 n u o 1.030 1.030 S

1.020 1.020

1.010 1.010 1.010 1.020 1.030 1.040 1.050 1.060 1.070 1.080 1.090 1.010 1.020 1.030 1.040 1.050 1.060 1.070 1.080 1.090 120 kHz 200 kHz

1.090 1.090

) h

(

t 1.080 1.080 s a r t 1.070 1.070 n o C

1.060 1.060 d e

e 1.050 1.050 p

S

d 1.040 1.040 n u o 1.030 1.030 S

1.020 1.020

1.010 1.010 1.010 1.020 1.030 1.040 1.050 1.060 1.070 1.080 1.090 1.010 1.020 1.030 1.040 1.050 1.060 1.070 1.080 1.090 Density Contrast (g) Density Contrast (g) TS Variation: fish

12 kHz 38 kHz 1.090 1.090

1.080 1.080 ) h (

t 1.070 1.070 s a r t 1.060 1.060 n 0 o C

1.050 1.050 d e

e 1.040 1.040

p 0 S

d 1.030 1.030 n u

o 1.020 1.020 S 1.010 1.010 1.010 1.020 1.030 1.040 1.050 1.060 1.070 1.080 1.090 1.010 1.020 1.030 1.040 1.050 1.060 1.070 1.080 1.090 120 kHz 200 kHz 1.090 -2 1.090 0 ) 1.080 -1 1.080

h 1 ( t s 1.070 1.070 0 a r

t -1 n 1.060 1.060 -2 o 0 C

d 1.050 -1 1.050 -1 e e -2 p 1.040 1.040 S 0 d n 1.030 1.030 0 u o

S 1.020 1.020 -1

1.010 1.010 -2 1.010 1.020 1.030 1.040 1.050 1.060 1.070 1.080 1.090 1.010 1.020 1.030 1.040 1.050 1.060 1.070 1.080 1.090 Density Contrast (g) Density Contrast (g) Ontogeny: Fish Swimbladder

106.5 mm

333 mm

Donaldson trout Acoustic Ontogeny

) 5000 2 SB Area 4000

3000 -30

2000

1000 -35

Dorsal Swimbladder Surface Area (mm 0 0 50 100 150 200 Experimental Day -40 2.4

2.2 SB>FB

Target Strength (dB) -45

2.0

1.8 38 kHz -50 120 kHz log(Swimbladder Length) log(Swimbladder 1.6 k: 1.1874 100 150 200 250 300 350 1.4

2.0 2.2 2.4 2.6 log(Fish Body Length) Total Length (mm)

Physiology

Feeding Gonad & Feeding

Ona 1990 Physiology: Fish Feeding

4000

) 2

3500

3000

2500 Starved Fed Dorsal Swimbladder Area (mm Area Dorsal Swimbladder cl vs dsba

2000 400 410 420 430 440 Caudal Length (mm)

Horne 2003 Physiology & Behavior: Fish at Depth

Surface Atlantic Herring

25 m

Blaxter et al. 1979 Swimbladder Pressure Experimental Setup

3 fish, pressurized to 9.0 kg m-3 dorsal and lateral tissue sound speed body and swimbladder digitized KRM modeled backscatter

20 L pressure chamber Swimbladder and Pressure

Lateral Dorsal

juvenile walleye pollock Swimbladder Dorsal Surface Area

600 WPOL6 (159.31mm) YOY 100 - 249mm (n=15) Juvenile 250 - 349mm (n = 20) 0.5 WPOL3 (196.29mm) Adult 350mm+ (n = 27)

WPOL5 (161.49mm) ) 500 2

0.4 ) 400

0.3 Elongation (minor/major) Elongation

300

0.2 Elongation

200 100 150 200 250 300 350 400 Dorsal Surface Area (mm Area Surface Dorsal Standard Length (mm)

100 0.25 YOY 100 - 249mm (n = 15) Surface Area (mm Juvenile 250 - 349mm (n = 20) Adult 350mm + (n = 27) 0 0.20 0 1 2 3 4 5 2 Pressure (kg m-2) 0.15 Area Fraction Area

0.10

YOY Juv Adult

0.05 100 150 200 250 300 350 400 Area Fraction Standard Length (mm) Dorsal Swimbladder Areas

Area Fraction 0.18 Average Shapes

YOY 0.16 Lateral Dorsal

YOY YOY 0.2 0.2 0.14 0.1 0.1 0.0 0.0 -0.1 -0.1 Scaled Y Y Scaled -0.2 -0.2 0.12 0.0 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.0

0.2 Juv 0.2 Juv 0.10 0.1 0.1 0.0 0.0 3 -0.1 -0.1 Scaled Y Y Scaled

-0.2 -0.2 0.08 Juv Adult 5 0.0 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.0 Adult Adult 6 0.2 0.2 Area Fraction (%) 0.1 0.1 0.06 0.0 0.0 150 200 250 300 350 400 450 -0.1 -0.1 Scaled Y Y Scaled -0.2 -0.2 Standard Length (mm) 0.0 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.0 Scaled X Scaled X

Horne et al. 2009 Dorsal Surface Area Changes ) 2

600 wpol 6 500 wpol 3 wpol 5 400 YOY mean

300

200

100

0 0 1 2 3 4 5

Swimbladder Dorsal Surface Area (mm Area Surface Dorsal Swimbladder Pressure (kg cm-2 above ambient) Swimbladder Volume Changes

wpol 6 wpol 3

2000 )

3 wpol 5 1600 wpol 6 wpol 3 1200

800

400

Swimbladder Volume (mm Volume Swimbladder 0 0 1 2 3 4 5 Pressure (kg cm-2 above ambient) Predicted Target Strengths Behavior

Individual orientation (tilt, roll, direction), activity, avoidance Group shoaling and schooling, avoidance

Position in Beam & Orientation

90 • KRM ambit from a 5 120 60 single fish (47 cm) 4

3 • Tilt = -5°, 0°, 5° 150 30 2 • Yaw = 0°-360° 1 • Distance-off-axis 0 180 0 0 (m) = 0, 2.5, 5, 7.5, 1 10, 12.5

2 210 330 3

4

240 5 300 270 Tilt, yaw, and distance off axis

38 kHz - 0° tilt 120 kHz - 0° 90 tilt 90 -28 -30 120 60 120 60 -30 -35 -32 -40 150 -34 30 150 30

-36 -45

-38 -50

180 -40 0 180 0

-38 -50

-36 -45 210 -34 330 210 330 -40 -32

-30 -35 0m 0m 240 300 240 300 2.5m -28 2.5m -30 5m 270 5m 270 7.5m 7.5m 10m 10m 12.5m 12.5m Tilt, yaw, and distance off axis

Tilt = -5° 12 Tilt = 0° -41 10 -40 12 8 -39 10 -38 6 -37 8 Tilt = 5° 4 12 6 distance off axis (m) distance off 2 10 4 5° 0 -5° 8 distance off axis (m) distance off 2 100 120 140 160 180 200 220 240 260 6 yaw angle (deg) 0 4

-31 100 120 140 160 180 200 220 240 260 -30 yaw (degrees) 2 -29 0 -40 axis (m) distance off

-28 -38 100 120 140 160 180 200 220 240 260 -27 -36 yaw angle (degrees) -34 -32 -30 Behavior: Individual Activity

Atlantic cod (38 kHz) Lavnun (120 kHz)

-40

-50

-60

-70 TargetStrength (dB)

0 200 400 600 800 Ping Number

Nakken and Olsen 1977

Horne et al. 2000 Orientation + Activity

108 cm Chinnook

Burwen et al. 2007 TS During Swimming Cycle

- free swimming Chinook - echo envelope changes with yaw & curvature - 2 tail beat cycles - pulse length a factor

Tail beat pattern species specific (Meuller et al. 2010) Burwen et al. 2007 Behavior: Group Avoidance

Individual: avoidance

Pitcher and Wyche 1983 Behavior: Group Boat Avoidance

Fernandes et al. 2000 Ensemble Fish Avoidance

- population flux - individual tilt angles

Figure 3a Vabo et al. 2002 Fish Tilt Animation Pattern Comparisons Acoustic Biological Perspective

Morphology anatomy material properties Ontogeny growth (body, scattering organs) sexual maturity Physiology feeding gonad production individual – orientation (tilt, roll, Behavior direction), activity, avoidance group – shoaling and schooling, avoidance Ranking Physical & Biological Factors

KRM model-based, non-dimensional ratios Tilt > Frequency > Length > Depth

Empirically measured, non-dimensional ratios

Length > Tilt >> Freq > Depth

Hazen & Horne 2003