However, mussels aren't likely to survive unless carefully repositioned in the bed. More and more these days, mussel fishing is done by scuba divers specially trained to collect only certain species and sizes of mussels. According to some mussel specialists, called malacologists, the fishermen do little harm to mussel populations compared to the damage wrought by dams, dredging, pollution and misguided human priorities. Mussels are filter feeders living on a diet of microorganisms gleaned from rich currents. Dams may slow river currents so water is not adequately mixed and enriched.
Mussels are also vulnerable to dredging and waterway traffic, which can bury a mussel bed in silt.
Silt also clouds the water, cutting down light penetration and production of microorganisms, the mussels' diet. Surprisingly, the meek Higgins' eye pearly mussel is among the most controversial of Wisconsin's endangered species. Because the Higgins' eye depends on the water quality of its limited habitat, several Mississippi River development projects have been delayed due to needed mussel impact studies. Others pass it off as bureaucratic hilarity or overkill by a bunch of screaming environmentalists. Moving a mussel bed or choosing a new building site are possibilities which need exploring.