This paper represents data obtained by 'Adriatic' sampler during mesozooplankton sampling experiments carried out at a station in the seawater inlet 'Veliko Jezero' on the island of Mljet. Data on vertical distribution, population density and sampling error between replicate samples collected by the 125 μm mesh net gauze demonstrate that the sampler tested can be efficiently used in quantitative investigations and microdistribution of mesozooplankton in shallow waters.