They are members of the bivalve family, one valve being cupped, the other flat. The extreme tightness of these valves, prolong storage capacity. Oysters are protandric, meaning they spawn as males immediately after maturing, then spawn as females as they grow larger. Spawning typically occurs in early summer, water temperature dependant, and it is during this period the meat will become thin, the result of increased energy expenditure by the animal. Size, shape, flavour and food value are all affected by their habitat, nutrient supply and water temperature.

Oysters are categorized for the commercial market into three major groups: standard, choice and fancy. Within these groups they may be further classified into small, medium and large. Goldwater Seafoods typically carries standard and choice, the majority of these types being small choice and large standard. Average length of small choice is 70-80mm. and 100-130mm. length on the large standard.