Fish Genetics and Aquaculture Biotechnology is an outcome of the International Conference on “Advanced Technologies in Fisheries and Marine Sciences” organized by the Center for Marine Science and Technology, Manonmaniam Sundaranar University. Representative contributions from the sessions on Transgenesis, Chromosome Engineering and Sex Control Molecular Endocrinology, Microbal Diseases and Vaccines, and Bioactive Compounds have been selected in order to bring about a comprehensive volume. Of the 12 selected articles, six are original contributions and the rest are comprehensive reviews. Hence, the book has a proporationate blend of original as also review contributions.