August 22, 2021: Echogram
Image courtesy of K. Boswell, Florida International University. Download larger version (jpg, 391 KB).
Echosounders have been employed in fisheries and ocean research for decades to detect fish, plankton, and features both on the seabed and in the water column. The ship-mounted echosounder being used on the R/V Point Sur during the From Aggregations to Individuals: Exploring Migrating Deep-Sea Scattering Layers Through Multiscale-Multimode Technologies in the Gulf of Mexico expedition was used to provide the first line of evidence for the location, depth, and relative abundance of organisms that make up the community within the Gulf of Mexico’s mesopelagic, or twilight, zone (200-1,000 meters/656-3,281 feet depth).
This image from an echogram generated during the expedition using the Point Sur’s echosounder shows backscatter from the water column from the surface (at the top of the image) to 1,000 meters (bottom of the image) over time (from left to right on the image). Higher backscatter is shown in green, to yellow and red. Lower levels are in blue and black. The pattern of vertical migration is reflected in the undulating pattern in the high backscatter.
From: Ship-based Echosounder: The First Reconnaissance Tool for Exploring the Deep Scattering Layers.