Biological Sound Scattering Studies. Part I. Initial Investigations in the Gulf of Mexico and Western North Atlantic.

• Main Authors: Zahuranec, Bernard J., Pugh, W. Lawrence, Farquhar, G. Brooke
• Other Authors: NAVAL OCEANOGRAPHIC OFFICE NSTL STATION MS
• Format: Text
• Language: English
• Published: 1970
• Subjects: Biological Oceanography; Acoustic Detection and Detectors; Acoustics; *MEXICO GULF; *ATLANTIC OCEAN; *SONAR SIGNALS; MARINE BIOLOGICAL NOISE; TARGET RECOGNITION; UNDERWATER SOUND; FISHES; OXYGEN; SOUND TRANSMISSION; SCATTERING; INVERTEBRATES; REVERBERATION; SAMPLERS; TABLES(DATA); Kidd; North Atlantic
• Online Access: http://www.dtic.mil/docs/citations/AD0877032; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=AD0877032

Since 1964 the Acoustical Oceanography Branch of the U. S. Naval Oceanographic Office has conducted bioacoustic investigations of deep scattering layers (DSL) in the Atlantic Ocean. The initial investigations before May 1967 were conducted primarily in three regions: the Gulf of Mexico, the southwestern Sargasso Sea, and the Gulf Stream. Biological collections at discrete depths were attempted with a six foot Isaacs-Kidd Midwater Trawl and a Be Multiple Plankton Sampler. The biological collections were sorted and identified to species (fish and some invertebrates) or to major groups (most invertebrates). The most abundant kinds of fishes collected belong to the families Myctophidae (Lanternfishes) and Gonostomatidae (bristlemouths). In general, 2 or 3 species of fishes in a collection were found to be more abundant than the rest, often making up the majority of fish in a sample. Investigation of the night surface scattering layers in the Gulf of Mexico in March 1967 indicates that the fish in these layers tend to be concentrated in a narrow depth range. Measurements in the Sargasso Sea in November 1965 show some correlation between the depth of occurrence of a deep scattering layer, an oxygen deficient layer, and an abundance of organisms. Collections from both areas as well as in the Gulf Stream agree with the concept that all three are regions of low productivity. Although a strong correlation was not established between DSL occurrence and the biological collections, these initial investigations suggest several findings that merit more intensive body. (Author)