On the frequency dependence of target strength of mature herring
Original version
This report is not to be cited without prior reference to the authorsAbstract
Mature herring (Clupea harengus), hibernating in Ofotfjord in
December 1991, was measured simultaneously at each of three frequencies:
18, 38, and 120 kHz. Measurements of the mean volume backscattering
coefficient were integrated over the water column and averaged over 0.1-
nautical mile intervals. Through a regression analysis of the resulting
values of area backscattering coefficient, performed for pairs of
frequencies, the ratio of backscattering cross sections o was determined.