Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 8157
Title: A high resolution acoustic imaging system to map interior fish morphology
Author: Dezhang Chu, J. M. Jech, S. D. Tomich, L. C. Hufnagle
Publication Year: 2015
Journal: Marine Technology Society Journal
Keywords: Acoustic image, attenuation, acoustic array, swimbladder, morpholoy,nonlinear,inversion,abundance,euphausiids,scattering,

 An Acoustic Imaging Microtome System (AIMS) was constructed to map the internal structure of fish. The system consists of two pairs of high-frequency (4.5 MHz) transmit and receive planar arrays, with one pair in the vertical plane and the other in the horizontal plane.  AIMS provides a series of acoustic images, analogous to microtome slices, along the length of a fish by combining electronically controlled sequential acoustic transmissions and receptions over 224 channels and a computer-controlled mechanical device that moves the acoustic arrays lengthwise along the fish.  AIMS measures the acoustic attenuation (extinction) along the direct ray paths of each transmit/receive channel pair that penetrates the fish body in a bistatic configuration. This results in a 2-D image of the interior morphology with 4-5 mm resolution.  The images can provide morphological information on the fish’s cheekbone, backbone, rib bone, skull, fins, stomach, and swimbladder, which is important for accurately modeling fish acoustic target strength, especially for non-swimbladder-bearing fish species.



Theme: Ecosystem approach to improve management of marine resources
Foci: Provide scientific support for the implementation of ecosystem-based management
Characterize the interaction between marine, freshwater and terrestrial ecosystem components.