Refined baseline inventories of non-indigenous species (NIS) are set per European Union Member State (MS), in the context of the Marine Strategy Framework Directive (MSFD). The inventories are based on the initial assessment of the MSFD (2012) and the updated data of the European Alien Species Information Network, in collaboration with NIS experts appointed by the MSs. The analysis revealed that a large number of NIS was not reported from the initial assessments. Moreover, several NIS initially listed are currently considered as native in Europe or were proven to be historical misreportings. The refined baseline inventories constitute a milestone for the MSFD Descriptor 2 implementation, providing an improved basis for reporting new NIS introductions, facilitating the MSFD D2 assessment. In addition, the inventories can help MSs in the establishment of monitoring systems of targeted NIS, and foster cooperation on monitoring of NIS across or within shared marine subregions.

This is the first study that presents concentrations of domoic acid detected in the whole shellfish tissue from breeding and harvesting areas along the Croatian coast of the Adriatic Sea during the period 2006 to 2008. Shellfish sample analyses after SAX cleaning procedures, using a UV-DAD-HPLC system, showed the presence of domoic acid in four species. The most prevalent of those species were the blue mussel (Mytilus galloprovincialis), followed by European flat oyster (Ostrea edulis), Mediterranean scallop (Pecten jacobaeus) and proteus scallop (Flexopecten proteus). Domoic acid, a potentially lethal phycotoxin that causes amnesic shellfish poisoning (ASP), was detected for the first time in January 2006 with the highest value of 6.5486 μg g^-1 in whole shellfish tissue. Pseudo-nitzschia spp. bloom events preceded these high domoic acid concentrations. According to this study, retention of domoic acid in the blue mussel M. galloprovincialis is more than 42 days. This investigation indicates the first presence of domoic acid in Croatian shellfish, but in concentrations under the regulatory limit (20 μg g^-1), therefore shellfish consumption was not found to endanger human health.

In order to test the response of phytoplankton to anthropogenic pressure, data of chlorophyll a concentration, phytoplankton abundance, and composition are analyzed in relation to anthropogenic pressure gradient and environmental variables such as temperature, salinity and nutrients. Investigated sites encompassed wide tropic range according to a preliminary determination of anthropogenic pressure, quantified through the LUSI index. Statistical analyses indicated nitrates and silicates as proxies of freshwater influence, and phytoplankton single metrics such as concentrations of chlorophyll a and abundances as indicators of anthropogenic pressure. Boundary values for different water quality classes for coastal waters under indirect freshwater influence (Type II) are obtained according to gradient between concentration of chlorophyll a and pressure index (LUSI), which empirically fit to exponential equation. The response of phytoplankton diversity was not linear, as the highest diversity was observed in the area with intermediate disturbance level. CCA analysis identified Skeletonema marinoii, Scrippsiella trochoidea, Guinardia flaccida, Leptocylindrus spp., Prorocentrum spp., Proboscia alata, Eutreptiella spp., and Pseudonitzschia spp. as local eutrophication indicators, whose abundances increased with nutrients loads

Annual dynamics and ecological characteristics of the genus Dinophysis spp. and associated shellfish toxicity events were studied from 2001 to 2005 during monitoring fieldwork in the coastal waters of the eastern Adriatic Sea. Analysis of the seasonal occurrence of Dinophysis species identified D. acuminata and D. sacculus as typical spring species, D. caudata, D. fortii and D. rotundata as summer and late summer species and D. tripos as a winter species. The highest abundances occurred when there were large differences between surface and bottom temperatures and salinities. D. caudata, D. sacculus and D. rotundata abundances had significant relationships with Δt, while the highest abundances of D. acuta, D. fortii and D. tripos were associated with high Δs values. Much higher abundances of D. caudata and D. fortii in offshore compared to inshore waters of the northern Adriatic Sea and the significant inverse relationship of these species' abundances with salinity suggested the possibility of their transport by Italian river-influenced coastal waters towards the eastern Croatian coast during the summer season and under stratified conditions. Toxicity events occurred more frequently in the more eutrophicated northern Adriatic Sea than in the southern Adriatic Sea and mostly succeeded the rainfall periods. Diarrhetic shellfish poisoning (DSP) toxin profile analyses identified okadaic acid and yessotoxin as the main DSP toxins occurring in Croatian waters.