Although aquaculture in the Mediterranean is a relatively young industry, finfish diseases have been reported to cause considerable problems and mortalities among the farmed stocks. In general, the farming activity and the open design of Mediterranean aquaculture systems allow the transmission of infectious pathogens within and among farm facilities. Fish health and biosecurity programmes at farms have focused on the most obvious pathways for transmission of pathogens, i.e. through transport of infected farmed fish from hatcheries, infected equipment, staff and vessels, as well as through water currents. However, little attention has been devoted to the potential risk of pathogen and disease transmission in Mediterranean open-sea aquaculture through movements of fish. The present study focuses on the importance of considering possible pathogen transmission between reared fish, farmed escapees and farm-aggregated fish when making management decisions.The study was financed by the EUproject ‘Prevent Escape’ (project number: 226885; www.preventescape.eu) and by the ‘FatFish’ project from the Spanish Ministry of Science and Innovation (CTM2009-14362-C02-01)

Fish welfare is an essential issue that needs to be tackled by the aquaculture industry. In order to address it, studies have been limited to a small number of species and the information is generally scattered. In order to have a consistent overview of the welfare of farmed fishes, we present the FishEthoBase, an open-access database that ultimately aims to provide information on the welfare of all fish species currently farmed worldwide. Presently with 41 species, this database is directed to all stakeholders in the field and targets not only to bridge the gaps between them but also to provide scientific information to improve the welfare of fish. The current text explains the database and presents an analysis of the welfare scores of 41 species, suggesting that (i) the general welfare state of farmed fishes is poor, (ii) there is some potential for improvement and (iii) this potential is related to research on species’ needs, but (iv) there are many remaining knowledge gaps and (v) current fish farming technologies do not seem to fully address welfare issues. The existence of a framework, such as the FishEthoBase, is proposed as fundamental to the design of strategies that improve the welfare of farmed fish.

Environmental enrichment is considered as a recommended tool to guarantee or improve the welfare of captive fish. This study demonstrates for the first time that structural environmental enrichment enhances cognition, exploratory behaviour and brain physiological functions of gilthead seabream (Sparus aurata). Seabream was reared in groups (n = 15) during 60 days under two different treatments: enriched tanks with plant-fibre ropes (EE) or bare/non-enriched tanks (NE). Fish were then exposed to a purpose-built maze for 1 h every second day in four trials. Analysis of video recordings showed that seabream under EE conditions presented higher overall exploratory behaviour, spatial orientation and learning capability compared to seabream from NE conditions. Results from brain monoamines analyses may suggest increased recent dopaminergic activity in telencephalon, known to be involved in learning processes; and increased serotonergic activity in cerebellum, involved in the coordination of balance, movements and orientation. In addition, EE-reared fish showed increased antioxidant activity in whole brain, with no apparent oxidative damage. Structural EE seemed to induce an hormetic response on juvenile seabream, improving their welfare status during captivity. Application of this kind of physical structure might be feasible at fish farms as a passive and non-invasive tool to improve welfare of intensively cultured seabream.