ANALYSING SHIPBORNE ADCP MEASUREMENTS TO ESTIMATE DISTRIBUTION OF SOUTHERN BLACK SEA ZOOPLANKTON

摘要

The results of the classical zooplankton studies, using net sampling are highly biased by clogging of the net, wire angle, uncertainty of the sampling depth, avoidance of larger organisms, etc. Moreover, since the analyse of the samples is time-consuming and tedious, only few samples can be examined and often fine structures of the distribution of the zooplankton can not be clearly shown. To overcome these problems and to obtain accurate vertical and horizontal distribution of the Black Sea zooplankton, Acoustic Doppler Current Profiler, which is routinely operated by physical oceanographers, was used. This device utilises acoustic backscatters to calculate the Doppler shift and, in turn, current velocity. The backscattered signal intensity from a ship-home 150 kHz ADCP, which is a measure of biomass, is compared with macro and meso-zooplankton samples collected with 30L Niskin water samplers in the southern Black Sea. Significant correlation between samples and backscatter intensities was obtained. A data set from a basin wide survey (July 1997) was used to obtain spatial and vertical distribution of zooplankton within Turkish EEZ. At a fixed station daily migration pattern of the zooplankton was studied and depicted in distribution diagrams.