This work is based on biotests being experimented at sea organisms - fish Serranus scriba. We were studying the activity of the mentioned fish in sublethal concentrations of organochloric pesticide - lindane. Besides the classic biotests, we used some new methods for neurotoxic testing that include the influence of this pesticide on circadian activity of fish as well as the variations in obtaining the positive conditioned reflexive responses. The results of these experiments show that this kind of fish reacts at the subtile changes of toxic concentration with the change of quality and rhythm in its conditioned reflexive reactions, that appeared earlier than other global signs of intoxication.

The determination of main and some biogenic and trace elements in the sea water of the Boka Kotorska Bay (Adriatic sea, Montenegro, Yugoslavia) was carried out by the atomic apsorption and emission spectrometric method (FAAS) and by the hydride technique AAS (HGAAS).

Results on sea - water quality control and level of pollution in the coastal Southern Adriatic (Montenegro, Yugoslavia) were discussed from data collected in 1997. Investigations from Boka Kotorska Bay, coastal sea up to Bojana river mouth and in front of Bojana river mouth were presented separately. For above mentioned areas, basic hydrographic parameters, as well as the level of bacterial contamination were examined throughout the year (1996/1997 period). In Kotor Bay, which is the shallowest and exposed to the strongest land - based sources, as in the Tivat Bay, some changes influenced by anthropogenic eutrophication were already found.

In this work influence of different concentrations of linear active substance (LAS-DBS) on activity of Serranus scriba CUV have been studied. Desynchronization of circadian rhythms is in direct correlation with LAS growing concentrations. The high disproportion was found between maximum permitted concentrations (3 mg/l) and our results which show the changes in fish behaviour at 0.2 mg/l LAS.