I can add that most sites were actually open twenty or so years ago, so they were tested. Then the Department of the Environment and Climate Change decided to concentrate on areas with a more commercial fishery. The other areas were closed by default. That is why we are now in a situation where, 20 or 25 years later, the areas are still closed by default. If a community organization wants to have a site reopened, it has to demonstrate quite exhaustively that the area is safe and secure for fishing, harvesting or production.
