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Based on the Med-Atlas 20002 database data at Mediterranean Sea surface, analysis of spatial and temporal variations of temperature and salinity, as well as, the search of its possible trends are the main goals of this work. The used statistical techniques allowed us to obtain various climatological fields of temperature and salinity, on a period of 45 years . Spatial and temporal analysis of those fields shows that the north-south gradient is weaker than the east-west gradient. The strongest variability in both mean fields is sharper in downwelling areas than anywhere else, showing the colder and less saline surface waters. Warmer and saltiest water surface are located in southeast of the Levantine basin. The eastern Mediterranean Sea is generally more saline than the western basin. The temperature seasonal cycle is more marked than the salinity seasonal cycle. The summer-winter thermal and saline fields are completely contrasted, especially in the northern Adriatic Sea. The largest positive peak of inter-annual temperature variability is encountered in 1994, the largest negative peak in 1992. Whereas those related to salinity observed in 1983 and in 1997 respectively. The decadal variations indicate a cooling of Mediterranean Sea surface in 1970s and a northward warming since 1980s that accelerated in 1990s. The eastern Mediterranean Sea exhibits a higher warming rate as compared to the western basin, but the average increase is about 0.2 °C/decade. The Salinity rising corresponds to the cooling periods and the decreasing is associated with the warming ones.

Purpose – Ballast water of merchant ship is a source of introduction of invasive species around the globe. The purpose of this paper is to present a quantitative risk assessment applied to a model port, the Port of Arzew in Algeria, and based on an analysis of this port’s shipping traffic. Design/methodology/approach – The risk assessment for introduction of invasive species is interpreted in the form of a probabilistic process, with a combination of two probabilities. The first probability is related to the ability of a species to arrive to the destination (recipient port), depending on the quantity of water ballast discharged and the duration of voyage. The second one is based on the species ability to survive in their new environment, which depends on the environmental similarity between donor port and Arzew port. Findings – This assessment’s outcome consists on a classification of scenarios regarding their acceptability. Consequently, it helped to classify donor ports according to a risk scale, from low risk to high-risk donor ports. Research limitations/implications – The phenomenon of invasion of aquatic species is a complex process. Factors such as adaptation and tolerance of species, the attendance or absence of predators, were not taken into account in this study. Practical implications – This study could be used by the maritime administration as a decision-making tool regarding the issue of exemptions under the IMO International Convention on the Management of Ballast Water and Sediments 2004. Originality/value – This is one of the first known studies in Algeria and dealing with ballast water management. The results of this assessment provide useful information to policy makers, in order to develop a national strategy to reduce the impact of shipping pollution on the marine environment.

Maritime transport is considered to be one of the main factors to transfer non-indigenous species (NIS), through biofouling of ships’ hulls and ballast water. Therefore, ports and marinas constitute hot spots for the introduction of species carried by international shipping and therefore are important sites for initiating biological monitoring. In this study, the port of Arzew (Algeria, Southern Mediterranean) was surveyed for the presence of NIS and cryptogenic species. The fouling communities of floating submerged structures and the hull of a fishing vessel were sampled with a scraper blade. After fixing and separating, the organisms were identified to the lowest possible taxonomic level. The results revealed the presence of 10 NIS and cryptogenic species, including: 1 Ascidiacea, 2 Bryozoa, 3 Crustacea, 1 Mollusca 1 Porifera, and 2 Polychaeta. Five species are reported for the first time from the Algerian coast. This study contributes to the knowledge of non-native species on the Algerian coast and in the Southern Mediterranean and establishes a baseline dataset for future assessments of NIS in ports of Algeria.

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