Acoustic data (Study of backscattering by hake swimbladders and determination of the hake target strength)

This project is to make laboratory measurements of the target strength (TS) of Pacific hake (Merluccius productus) as a function of frequency and the angle of orientation.The specific tasks include the following:

1. Calibrate the sonar at the Henderson Acoustic Facility at the Applied Physics Lab (APL) at the University of Washington (UW).

2. Conduct measurements of target strength (TS) of Pacific hake swimbladders at frequencies 15 kHz to 40 kHz vs. all angles of orientations (4solid angle, alone with swimbladders inflated with a number of different air volumes that may reflect the variation in swimbladder volume at different depths or pressures), and process and analysis the data.

The project involves collaborative research activities. Drs. Dajun Tang and Darrell Jackson, and Russell Light at the APL will be funded by the NWFSC ($90K) to conduct the experiments and analyze the data. Larry Hufnagle and Dezhang Chu (NWFSC) will provide fish (hake) and assist with the experiments. We expect to obtain information of hake TS as a function of frequency and angle of orientation, and write a peer-reviewed paper. Although this project has ended officially, the analysis and publication effort will by continually funded by APL/UW. Raw acoustic data