The species check-lists are important to know the local biodiversity. If they are harmful and/or exotic they can cause environmental damages. The portuary regions' aquatic biota survey is valuable to inform which are the high risk species in the water (exotic or harmful species). The species can be caught when the ships are anchored in Parana harbors during the ballast taken. After that, these species can be transferred to the next harbor where it will be discharged, so it starts the biological invasion. In this article the marine and estuarine diatoms of Parana have been listed based on some issues that have been published since 1918 and over the results of ALARME Project (Ballast Water: Risk analysis, Environmental Management Plan and Monitoring of Exotic Species in Paranagua Harbor, Parana) in the Estuarine Paranagua Complex. An amount of 789 specific taxa was recorded and distributed in 167 genera on Parana shore. Among the 789 a number of 575 specific taxa is distributed in 152 genera which were recorded in the Estuarine Paranagua Complex. Some of these species are considered potentially harmful for their toxins production i. e. Amphora coffaeformis and Pseudo-nitzschia spp. The other ones have harmful effects because of anoxia due to the excess of biomass decomposed by bacteriae during the blooming periods. Furthermore it can happens excessive oxygen consumption by algae during breathing. These species are Asterionellopsis glaciallis, Cerataulina pelagica, Coscinodiscus spp, Cylindrotheca closterium, Leptocylindrus spp and Skeletonema costatum. Furthermore, Chaetoceros spp, have setae that damage the fishes' gills causing mass mortalities in some regions. Some species found in samples of the ALARME project are new records for the Parana coast such as Bellerochea horologicales, Biremis circumtexta, Gyrosigma macrum, Licmophora remulus, Nitzschia behrei, Pseudo-nitzschia calliantha, P. multisseries and Thalassiosira subtilis var. máxima.
harmful diatoms; check-list; ballast water; Parana
