Previous Long-Range Acoustic Efforts
1963-68 (Weston, Revie et al.) Perranporth, England military sonar, 18 m aperture, 1.5kHz, 20 kW, detected fish schools up to 65 km.
1971 (Rusby et al.) GLORIA towed sidescan, 10 m aperture, 6.5kHz, tracked herring schools to 15 km.
1975 (Hewitt et al.) vessel-based 30kHz sidescan, California pelagic fish school mapping to 500 m.
1992 (Nero and Huster) explosive sources (1.8 kg SUS) with 122 element towed receiver array, detected pelagic salmon up to 4 km, 500 Hz swimbladder resonance.