Shipping traffic and introduction of non-indigenous organisms : Study case in two Italian harbours
In order to study the role of ballast water in introducing non-indigenous organisms in the Mediterranean Sea, the maritime traffic was analysed in the harbours of Naples and Salerno, which are important commercial ports in southern Italy. The 2001 data concerning the number of ships, the cruises’ length and the source of arrivals, were taken from harbours’ offices logbooks. In both harbours, the Mediterranean traffic was higher compared to the world sea-borne traffic that was mainly coming from North East Atlantic countries. The mean length of travels was of 1 week while the longest voyages were from Australia (3 weeks). A theoretical amount of ballast waters discharged during 1 year was provided by using an European model. A total of 55,738 and 118,339 ton of foreign ballast water are released annually in Naples and Salerno, respectively, to which theoretically correspond the entry of 4,977,403 (Naples) and 10,366,496 (Salerno) phytoplanktonic specimens.
The Black Sea — A Recipient, Donor and Transit Area for Alien Species
There is evidence of large-scale biological contamination of the Black Sea ecosystem by nonindigenous species: benthic communities are mostly altered in the western and northwestern parts of the Sea, while the pelagic part are affected in the whole basin. Recent invasion status of the Black Sea is briefly reviewed with special focus on most successful recent invaders.
Phylogenetic analyses of Caulerpa taxifolia (Chlorophyta) and of its associated bacterial microflora provide clues to the origin of the Mediterranean introduction
The accidental introduction of Caulerpa taxifolia into the Mediterranean is no longer under dispute. What has eluded researchers until now, is definitive evidence for the original, biogeographical source population. Here we present two independent lines of evidence that support an Australian origin for the Mediterranean populations of C. taxifolia. First, we reanalysed algal rDNA‐internal transcribed spacer (rDNA‐ITS) sequences, combining previously published sequences from different studies with 22 new sequences. The ITS sequence comparison showed that the Australian sample is the sister group of the Mediterranean–aquarium clade. Second, cloned bacterial 16S rDNA gene sequences were analysed from the associated microflora of C. taxifolia collected from Australia, Tahiti, the Philippines and the Mediterranean. Five bacterial lineages were identified, of which three were dominant. Alpha Proteobacteria were the most abundant and were found in all samples. In contrast, members of the beta Proteobacterial line and Cytophaga‐Flexibacter‐Bacteroides line (CFB) were mainly associated with Mediterranean and Australian samples. Frequency distributions of the five bacterial lineages were significantly different among biogeographical locations. Phylogenetic analyses of the 54 bacterial sequences derived from the four C. taxifolia individuals resulted in a well‐resolved tree with high bootstrap support. The topologies of the beta Proteobacteria and CFB mirror the geographical sources of their algal hosts. Bacterial–algal associations provide an identification tool that may have wide application for the detection of marine invasions.