Oysters are shellfish. They live in brackish saltwater bays and tidal areas. Oyster farming is a great way to improve water quality, because Oysters are filter feeders, who do their part to clean local waters, promoting growth of underwater grasses and other marine life.
NOAA. Historical Maps and Charts audio podcast. National Ocean Service website, https://oceanservice.noaa.gov/podcast/july17/nop08-historical-maps-charts.html, accessed on 8/13/17.