CCAMLR

A methodology is described which when applied to data from an acoustic survey will yield mean krill density along an arbitrary section through the survey area, giving results compatible with the specifications given in wg-krill-93 Appendix D. A program written to calculate such sections is also described and example output displayed. A similar program calculates current speeds normal to a section given an oceanographic dataset of current direction and speed. The two programs produce compatible vectors of krill density and current speed along specified sections

Conditions for precise measurement of in situ fish target strength (TS) are empirically studied and two indexes are introduced for this purpose. One is the number of fish in the effective reverberation volume which contributes echo formation at a certain instant and the other is the percentage of the multiple echoes which is derived from a residual of the single echo extraction. With the decrease of both indexes measured target strength approach a certain asymptotic value which is admitted as reliable from the past study. This shows the existence of some threshold values and below these threshold values TS measurement will be successful. The effectiveness of both indexes is confirmed by the data set obtained from one large same fish school in the eastern shelf of Bering sea during the intership calibration between Japanese and U.S. vessels on 15 and 16 August 1991.

Published in J.Mar.Acoust.Soc.

In 1993 Ukraine has recommenced krill fishing which was terminated in 1993. It is conducted by two vessels BAT GRIGORY KOVTUN and RKTS GENERAL PETROV. Scientific observer M. Speranskaya, YugNIRO scientist is on board the latter one.
The fishery and scientific information given in this paper is based on operative data. That is why some correction of these data is possible after the observer’s return from the cruise.