Cefas is an internationally renowned aquatic scientific research and consultancy center. It aims to be the prime source of high quality science used to conserve and enhance the aquatic environment, promote sustainable management of its natural resources, and protect the public from aquatic contaminants. Cefas provides research, advisory, consultancy, monitoring and training services to a large number of clients worldwide. It has a huge range of resources and expertise, with more than 500 staff based in 2 UK laboratories, its own ocean-going research vessel, and over 100 years of experience. Cefas is an executive agency of the UK governments Department for Environment, Food and Rural Affairs (Defra).The purpose-built Weymouth laboratory was officially opened in 1995. It contains modern facilities for fish and shellfish disease diagnosis and research, including scanning and transmission electron microscopes with an X-ray micro-analysis suite for biological and environmental samples. The laboratory has been designated as both the European Community Reference Laboratory and the UK National Reference Laboratory for monitoring bacteriological and viral contamination of bivalve molluscs. In addition, the laboratory is the designated Community Reference Laboratory for crustacean diseases and the OIE collaborating centre for aquatic animal diseases.