Figure 5. Spatial distribution of area backscatter.

Area backscattering coefficient (m2 nautical mile−2), from the mesopelagic deep scattering layer. Recordings from multi-ship surveys using calibrated SIMRAD 38 kHz echosounders integrating down to 750 m depth (1000 m after 1999). Composite image of data from 1996–2009 during June–July.