The Asian kelp Undaria pinnatifida (Harvey) Suringar 1873 was found for the first time in Belfast Lough, Northern Ireland during 2012 and was probably established in 2013. This currently is the most northern locality in Europe. The recent expansion around Britain is likely to continue with further colonisation in Ireland and extension to Scotland. Conditions are suitable for colonisation of Celtic, North and perhaps Norwegian Sea coasts, where it is likely to become an important fouling organism on marinas, aquaculture equipment, and other structures. Its preponderance on marina and other pontoons suggests artificial structures are its preferred initial sites of colonisation.

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The lagoon of Boughrara is the largest lagoon in Tunisia. For several decades it has been subject to the impact of increasing anthropogenic activities, and also to environmental stressors due to climate change and the low renewal of its waters. The present work is a contribution to the study of the functional organization of the benthic macrofauna of the lagoon of Boughrara 3 years after the extension of the channel 'El Kantra' which connects this lagoon to the open sea. In total, 13 stations facing the main prospective sources of disturbance and in areas likely to be more polluted were seasonally sampled during 2009 -2010. Seasonal monitoring of the abiotic parameters shows a spatial heterogeneity linked to environmental and anthropogenic factors, including hydrodynamics, sedimentary texture and anthropogenic activities. The community of benthic macrofauna is generally poorly diversified at lagoonal-marine stations undergoing influences of both the marine and lagoon environment. The extreme seasons in terms of temperature and salinity seem to have an important role in the reduction of biodiversity in the lagoon of Boughrara. The trophic structure of the macrobenthic community is generally dominated by selective deposit feeders, and seems to be linked more to the availability of trophic resources than to disturbance.

Abstract:The lagoon of Boughrara is an almost closed system, with limited hydrological connections with the sea. Over the past several decades, the lagoon has been exposed to increased pollution due to growing human activities in the surrounding area. From 2004From -2007, the channel "El-Kantra" connecting the lagoon to the sea has been extended with increased mixing with marine waters. In this work, we monitored the ecosystem of the lagoon after its rapid exposure to development and associated pollution. Two marine surveys were carried out in winter 2010 and then in winter 2013; the sediment was sampled and the principal physical and chemical parameters were measured at 13 stations. Results show that aspects of the environmental quality of the lagoon have improved from 2010 to 2013, most likely due to the extension of the channel whereby lagoon waters are better mixed resulting in improved physico-chemical conditions over this timeframe. Nevertheless, the study of the macrobenthic community did not show any improvement. On the contrary, the species richness and the abundance of the macrofauna have decreased, and some tolerant species such as bivalves (Abra alba and Cerastoderma edule) have increased in abundance. This demonstrates continued impacts on the lagoon ecosystem.

The purpose of this study was to determine the phylogenetic relationships among the primary betanodavirus strains circulating in Tunisian coastal waters. A survey was conducted to investigate nodavirus infections at 15 European sea bass Dicentrarchus labrax and gilthead sea bream Sparus aurata farming sites located along the northern and eastern coasts of Tunisia. The primary objective of the study was to create epidemiological awareness of these infections by determining phylogenetic relationships between the main betanodavirus strains circulating during the period 2012-2019, using RNA1 and/or RNA2 genome segments. Approximately 40% (118 of 294) tissue pools tested were positive for betanodavirus. Positive pools were distributed across all of the sampling sites. While fish mortalities were always correlated with the presence of virus in sea bass, a severe outbreak was also identified in sea bream larvae in 2019. Phylogenetic analysis revealed that almost all Tunisian strains from both sea bass and sea bream irrespective of outbreaks clustered within the RGNNV genotype. It is noteworthy that samples collected during the 2019 outbreak from sea bream contained both RNA1 and RNA2 fragments belonging to the RGNNV and SJNNV genotype, respectively, an indication of viral genome reassortment. To our knowledge, this is the first report of reassortant betanodavirus in Tunisia.