I read the article and I did not see anything about fossilized. Even searched the page to make sure. These are the remains of illegally harvested clams.
I imagine this is just the processing center and the people operating it were paying fishermen a hefty sum to bring in whatever they could. The fishermen probably complied because it helped supplement their income. Hence the reason it went on for so long.
This is sad not because of the harvesting of clams, people got to eat. But by being illegal, this means the clams were over harvested from a specific area. It will take several years to rebuild the clam population in the region so that they can be sustainably harvested once again. The main population affected will be the local fishermen and their families. The people running this operation will pick up and move to the next area.