The Language of Oysters

Adductor muscle: The main muscular system in bivalve mollusks, i.e. in clams, scallops, mussels, oysters, etc. Bivalve mollusks generally have either one or two adductor muscles. The muscles are strong enough to close the valves of the shell when they contract and they enable the animal to close its valves tightly when necessary.

Bivalve: A mollusk that possesses a hinged shell and a hatchet-shaped foot that allows them to burrow. Oysters are sessile bivalves.

Cultch: Material that larval oysters use as substrate for settlement. The best cultch for oysters is natural oyster shell.

Denitrification: A microbially facilitated process of nitrate reduction that may ultimately produce molecular nitrogen (N2) through a series of intermediate gaseous nitrogen oxide products.

DERMO: An oyster disease caused by a microscopic parasite.  It is harmful to oysters but not to humans.

Dissolved oxygen (DO): A relative measure of the amount of oxygen that is dissolved or carried in a given medium.

Geographic information system (GIS): A system designed to capture, store, manipulate, analyze, manage, and present all types of geographical data.

Estuary: A waterway where freshwater from a river or stream comes into contact with salty ocean water. It is characterized by water with salt content between that of fresh and marine environments. Estuaries are among the most diverse and biologically productive ecosystems on Earth.

Hemolymph: Fluid that fills the circulatory system of arthropods and some mollusks including the oyster.  Hemolymph is analogous to blood in vertebrates.

Hypoxia: Refers to low oxygen conditions. Oxygen depletion is a phenomenon that occurs in aquatic environments as dissolved oxygen (DO; molecular oxygen dissolved in the water) becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms living in the system.

Larvae: Free swimming planktonic life stage of a developing oyster.

Mantle: The two fleshy folds of tissue that cover the internal organs of the oyster and are always in contact with the shells but not attached to them.

MSX: An oyster disease caused by a microscopic parasite.  It is harmful to oysters but not to humans.

Oyster Reef:  The environmental structure created by oysters growing on a firm substrate such as shell, while subsequent generations attach to the older oysters, often forming clusters.

Plankton: Any organisms that live in the water column and are incapable of swimming against a current.  They provide a crucial source of food to many large aquatic organisms.

Pseudofeces: The output result of the way that filter-feeding bivalve mollusks, such as oysters, get rid of suspended particles which have been rejected as unsuitable for food. The rejected particles are wrapped in mucus and are expelled without having passed through the digestive tract and are therefore, not actually feces.

Salinity: The saltiness or dissolved salt content (such as sodium chloride, magnesium and calcium sulfates, and bicarbonates) of a body of water.

SCUBA: Self-Contained Underwater Breathing Apparatus.

Setting; Settlement: The metamorphosis from the planktonic (free-swimming) larval form to the benthic adult form. When oysters set or settle, they permanently attach to a hard substrate.

Shucking: Opening an oyster.

Side-Scan Sonar: A category of sonar system that is used to efficiently create an image of large areas of the sea floor.

Spat: The life cycle of the oyster begins with a free-swimming larval stage that eventually attaches to a hard substrate forming an oyster spat. The spat commences a growth period that is classified into sub-adult and adult phases.

Spawning: Producing and releasing gametes (eggs or sperm). Males often spawn first and the presence of sperm in the water is a stimulant to the females. Gametes are released into the water where fertilization occurs.

Substrate: A surface on which an organism grows or is attached.

Umbo: A knob-like limb arising from the surface of an oyster shell, near the hinge. Often refers to the anterior or hinge end of the oyster.

Valve:  One of the two shells of the oyster.

Zygote:  Cell formed by the union of egg and sperm.

The Horn Point Oyster Lab Hatchery in Cambridge, Maryland spawns and raises oysters until they are ready to live in the Chesapeake Bay. One of the largest hatcheries on the East Coast, Horn Point is a major partner of the Oyster Recovery Partnership.