Fish Population and Behavior Revealed by Instantaneous Continental-Shelf-Scale Imaging Nicholas C. Makris, Massachusetts Institute of Technology Purnima.

Fish Population and Behavior Revealed by Instantaneous Continental-Shelf-Scale Imaging Nicholas C. Makris, Massachusetts Institute of Technology Purnima Ratilal, Northeastern University Deanelle Symonds, Massachusetts Institute of Technology Srinivasan Jagannathan, Massachusetts Institute of Technology Sunwoong Lee, Massachusetts Institute of Technology Woody Nero, Naval Research Laboratory

Coventional Fish-Finding Sonar R/V Henlopen 80 m 10 m Frequency: 38 kHz Beamwidth: 6.8 o Layer Strength (dB) Approx. 2 km 0 m 100 m 50 m Echosounder section through the fish -20 -30 -40 -50 -60 -70 -80 Average Ship Velocity: ~3 m/s Example MAE2003 Output Courtesy of NRL

Measuring and Monitoring Fish Populations with Ocean Waveguide Remote Sensing (OAWRS)

Location of 2003 OAWRS Survey: Continental Shelf South of NY

Remote Imaging in the Continental Shelf The Geoclutter Program

US Research Ship (RV) Oceanus: OAWRS Receiver Ship RV Endeavor: OAWRS Source Ship OAWRS 2003 Survey Fish Groupings Moored Vertical Source Array Towed Receiver Array RV Henlopen: Conventional Fish Finding Sonar (CFFS) Survey CFFS Transect Local Water Depth ~80-100m

Geometric Spreading: Free space & waveguides Free Space (CFFS): Spherical Spreading Loss in Free Space 2-D Waveguide (OAWRS) : 1-D Waveguide: No Geometric Spreading Loss in a 1-D Waveguide Cylindrical Spreading Loss in a 2-D Waveguide A A r2r2 r1r1 ρ2ρ2 ρ1ρ1 H A A

Movie Box Source Receiver A small fish group Continental Shelf Edge ConsolidatedShoal 80m 70m 100m 120m 800m Eastings from Source (km) Northings from Source (km) 09:32 EDT Vacuoles within large shoal Fish Bridges connecting population centers Population Centers Instantaneous OAWRS Image of Areal Fish Population Density

Fish Species Found in the Continental Shelf South of NY Black Sea Bass Silver Hake (whiting) Atlantic Herring Spotted Hake Red Hake Atlantic Mackerel DogfishScup

Instantaneous Wide-Area Detection and Imaging of Fish Schools May 14: 09:32:25 EDT May 15: 08:49:55 EDT 70m 80m 100m 120m 70m 80m 100m 120mb 200m 400m

Spatial Frequency f s (1/m) Spatial Fish Population Density Spectrum (fish/m 2 ) 2 / (1/m) Large Shoal Present Scattered Fish Groups Spectral density is proportional to f s -1.5

0369 12 Eastings from Source (km) -6 -9 -12 -15 -18 11:59:05 EDT 12:09:55 EDT 12:19:55 EDT 12:29:55 EDT 100m100m100m100m α β γ δ Echogram corresponding to CFFS line transect (11:54:39-12:39:01 EDT) α β δ Northings from Source (km) γ A B C D Spatial and Temporal Correlation: OAWRS vs CFFS

May 14: Fish Population, Area, and Coherence Area for various density thresholds for various density thresholds Eastern Daylight Time (Hours) Total n A >0.2 n A <0.2 n A >1 n A <1 Consolidated Shoal Largest fraction 2 nd largest fragment -6 -9 -12 -15 -18 036912 (km) Population (Millions) Area (km 2 ) Coherent Area (km 2 ) Consolidated Shoal Largest fraction 2 nd largest fragment

Time Scales of Total Population Change Time Lag (min) Frequency (cycles/hr) Normalized Temporal Fish Density (cyles/hr) -1 Autocorrelation Total n A >0.2 n A <0.2 n A >1 n A <1 Population(Millions) Eastern Daylight Time (Hours)

Relative Speed Between Two Populations Centers -6 -9 -12 -15 -18 0369 12 (km) May 14: Time series of Relative Speed Relative Speed (m/s) Eastern Daylight Time (hours) Probability (km)

This new remote sensing technology “is like Doppler weather radar for fish” because it (1) Instantaneously detects, images and continuously monitors fish population and population density over continental-shelf scales and so (2) reveals the detailed behavior of fish schools over wide areas. It will be used to explore marine biology in the Gulf of Maine in 2006, as part of the Census of Marine Life Program, with support from the Sloan Foundation, the National Oceanographic Partnership Program and ONR. Conclusions

Gulf of Maine: Geography

2000 2001 2002 2003 2004 2005 Atlantic Herring Distribution 2000-2005

Average Atlantic Herring Distribution 1999-2005

LONG-RANGE BISTATIC OPS R/V OCEANUS R/V ENDEAVOR 115-m to 230-m 70-m to 140-m 37-m to 52-m XF-4: 7-element MOD-30: 10-element Variable Full aperture: 277-m ULF aperture: 189-m LF aperture: 94.5-m MF aperture: 47.25-m HF aperture: 23.625-m Triplet aperture: 15.4-m 24-m to 55-m Variable Horizontal Receiving Array Variable Vertical Source Array Seafloor TOWED RECEIVER ARRAY MOORED SOURCE ARRAY MAIN ACOUSTICS EXPERIMENT APRIL-MAY 2003

Loading onto RV Endeavor OAWRS Vertical Source Array

OAWRS Towed Receiver Array on Spool on RV Oceanus

Expected acoustic intensity level in a fluctuating ocean (Ratilal and Makris, JASA 2005; Chen, Ratilal, Makris JASA 2005) Frequency: 415 Hz (Low pitch A)

Distance (km) Fish Inversion: Intermediate Steps One Way TL from Source dB Re 1m One Way TL from Receiver dB Re 1m Two Way TL Convolved with Beam Pattern of the Array dB Re 1m SPL: May 14, 09:33:25 EDT LFM: 390-440 Hz dB Re 1uPa Scattering Strength Fish Density Distribution Fish/m 2 Distance (km) dB