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the coast. The highest S v values were observed along 
the coast of Costa Rica and the coast of Mexico south 
of the Gulf of Tehuantepec (16°N, 95°W). 
In 1993, <S V was high in the Gulf of California and 
along the Pacific coast of southern Baja California 
(Fig. 5). S v was generally low in the northern and 
Figure 4 
Maps of daily (0800-1600) and nightly (2000-0400) 38-kHz mean volume scattering strength (S v , dB) 
in the surface layer (0-100 m) during PODS92 surveys, 28 July -2 November 1992. 
