In conclusion, we have described a rapid, inexpensive and nondestructive method for storage, isolation and amplification of high-quality DNA, ideal for population studies involving the analysis of large numbers of samples, representing also a cheap alternative to the freezing storage and to DNA extractions based on commercial kits. Furthermore, this is the first methodology using buccal cells and external mucus as fish DNA source. The practical membrane format takes up minimal space, can be posted as a normal letter and allows efficient downstream processing, such as a molecular marker analysis.