Glossary

Adductor muscle large muscle near centre of scallop that pulls the two valves together Algae aquatic plants that reproduce by cell division or spores Anoxia deficiency or absence of oxygen in the blood and tissues Anterior front or head

Banjo filters in hatchery terminology, a ring meshed on both sides affixed to the outflow of a tank preventing larval loss through drain
Blastula a hollow ball of cells, one of the early stages of embryonic development
Bivalve mollusc of the Class Pelecypoda, having a shell of two valves that are joined by a hinge
Byssus thread-like filaments used by bivalves to attach themselves to a substrate
Cilia hair-like structures whose rhythmic beat induces a water current in bivalves
Cleavage the series of mitotic divisions, usually occurring with no increase in cytoplasmic mass that first transforms the single-celled zygote into a multicellular blastula
Ctenidia leaf-like appendages that function in respiration and filtration of food from water (used interchangeably with the term gills)
Cultch material used to collect bivalve spat
Detritus fragmented or decomposing organic material from plant and animal remains
Diatom a single-celled algae of the Class Bacillariophyceae; cells are enclosed in a siliceous shell called a frustule, cells can form chains
D-larva the early veliger larval stage of bivalves, also known as straight hinge larva
Dribble spawners in this case used for scallops which do not spawn completely, but partially over a period of time
Dorsal the back or part of an organism away from the ground
Downwelling in hatchery terminology, a growing system in which the flow of water enters at the top of a spat holding container (compare with upwelling)
Ectometabolites a product of metabolism
Embryo organism in early stages of development; in bivalves, prior to larval stage
Epiphytes animals or plants living on the surface of the seabed or other substratum
Eye spot simple organ that develops near centre of mature larvae of some bivalves and is sensitive to light

Fecundity the potential reproductive capacity of an organism or population expressed in the number of eggs (or offsprings) produced during
each reproductive cycle
Fertilization union of egg and sperm
Flagellate group of single-celled algae characterized by having a locomotory organ called a flagellum
Follicle small sac-like structure in the ovary, a group of cells surrounding the oocyte and probably concerned with its nutrition
Gamete mature, haploid, functional sex cell capable of uniting with the alternate sex cell to form a zygote
Gametogenesis process by which eggs and sperm are produced
Gastrula the embryonic stage of development consisting of two layers of cells enclosing a sac-like central cavity with a pore at one end
Gill a leaf-like appendage that functions in respiration and filtration of food from water (see ctendia)
Gonadal Index in this case the relationship of gonad weight to shell weight, reflecting gonad growth or depletion
Gonads the primary sexual organ: testis producing sperm or ovary producing eggs
Growout the process of growing seed to market size
Hermaphrodite having both male and female reproductive organs in the same individual (animal)
Hypoxia insufficient levels of oxygen in blood or tissue (short of anoxia)
Inoculum culture of an organism (alga, rotifer), which is used as a starting point for another culture
Larva a stage of bivalves from the embryo to metamorphosis Mantle the soft fold enclosing the body of a bivalve which secretes the shell
Meiotic division process in which normal number of chromosomes (2n) is reduced to the haploid (n) number
Metamorphosis in bivalves, the period of transformation from the larval to the juvenile stage
Microalgae small cell-size algae, either single celled or chain forming diatoms, cultured as foods for larvae and spat in a hatchery
Muscle Index in this case, the relationship of muscle weight to shell weight, reflecting muscle growth or depletion
Oocyte Cell, which develops into an ovum
Ovary the sex organ which produces the egg or eggs in a female organism
Pediveliger Larval stage of molluscs that still has the swimming ciliated organ (velum) and sensitive foot needed for settlement and attachment
pH a measure of acidity
Plankton floating or weakly swimming aquatic organisms, can be phytoplankton (plants) or zooplankton (animals)
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Polar body minute cells released during meiotic division of the egg after the sperm has penetrated the egg; contains excess chromosomal material to produce a haploid egg
Posterior the rear, away from the head
Primary oogonia arising from primordial germ cells during the initial (premeiotic) stage of oocyte development, and differentiates into an oocyte in
the ovary
Prodissoconch Bivalved shell formed by larva prior to metamorphosis. It may be possible to distinguish an earlier, smaller prodissoconch-I from a
later, larger prodissoconch-II that encloses the entire animal
Pseudofaeces false faeces, waste material not taken into the digestive tract Seed a young scallop with no specific definition to size
Settlement behavioural process when mature bivalve larvae seek a suitable substrate for attachment
Shell height in scallops, the straight line distance measured perpendicularly from the umbo to the ventral margin of the shell
Shell length in scallops, the straight line distance from the anterior to the posterior margins of the shell
Spat a newly settled or attached bivalve (also termed post larval or juvenile in bivalves)
Spatfall the settling or attachment of young bivalve molluscs, which have completed their larval stages
Spawning release of ova, fertilized or to be fertilized
Statocyst formed by invagination of the epithelium in bivalve larvae potentially providing the ability to detect gravity
Straight-hinge early part of larval stage, sometimes termed D-stage larva
Testis male reproductive organ
Trochophore the first free-swimming planktonic stage of a mollusc larvae or bivalve embryo
Umbo beak-like projections at the dorsal part of the shell; it is the oldest part of a bivalve shell (also called the umbone)
Upwelling in hatchery terminology, a growing system in which a flow of water is induced through the base of a spat holding container (compare
with downwelling)
Veliger larva the larval stage of most molluscs, characterized by the presence of a velum
Velum ciliated locomotory organ of the larva
Ventral pertaining to the under or lower side of an animal Vitellogenesis formation of the yolk of an egg
Zygote diploid cell resulting from union of male and female gametes