The objective of the project is to monitor the status and trends for a selection of the most important brook crayfish population. The project shall, through the use of new technology, implement the monitoring of signal crayfish based on a fixed grid of areas. The project shall collect population density data for brook crayfish by using fish pots and pulse trawling, in addition to individual data such as length, sex, sexual maturity and the ecdysis status. The contract has 3 options.