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A calculating table provided by manufactures to select equipment


Physical factor which affects the development and/or survival of an organism


In aquaculture systems: the mechanical mixing of air and water; this generally refers to a process by which gases contained in air are transferred across the air - liquid interface (in contrast with the transfer of oxygen alone)


A gelatinous colloidal extractive of a red alga (as of the genera Gelidium, Gracilaria, and Eucheuma) used especially in culture media or as a gelling and stabilizing agent in foods

air blower

A device that pumps large quantities of ambient air at low pressure, through an air distribution network to aerate water by air stones or air diffusers


Stone - like porous structure used as an air diffuser in water to promote the transfer of oxygen and the removal of carbon dioxide

algal inoculum

Algal cells belonging to a population in exponential growth phase used for incubation to launch new algal culture vessels


Relates to the existence of a substance and especially an element in two or more different forms (as of crystals) usually in the same phase


Referring to a condition or process where gaseous oxygen is not present or not necessary


Loss of sensation with or without loss of consciousness


A preliminary case history of a medical patient (also applied for veterinary sciences)


Deficiency or absence of oxygen in the blood and tissues


Free or freed from pathogenic microorganisms (an aseptic operating room)


An apparatus (as for sterilizing) using superheated steam under high pressure


Free from other living organisms


Infection caused by bacteria


In the context of the manual: a unit of pressure equal to a million dynes per square centimeter

beach seine

Net hauled by two or more people near the shore and made of four parts: float line, webbing lead line and poles


A deep widemouthed thin - walled vessel usually with a lip for pouring that is used especially in science laboratories

benthic organism

Organisms occurring at the bottom of a body of water


The component of the treatment units of a culture system in which the removal of organic matter takes place and dissolved metabolic by - products are converted (mainly oxidized) as a result of micro - biological activity. The most important processes are the degradation of organics by heterotrophic bacteria and the oxidation of ammonia via nitrite to nitrate

biological filter

See biofilter


The embryo - forming portion of an egg with discoidal cleavage usually appearing as a small disc on the upper surface of the yolk mass


A cell produced during cleavage of a fertilized egg

branchial arch

Related of, relating to, or supplying the gills or associated structures or their embryonic precursors


In aquaculture: sexually mature specimens of both sexes kept for the purpose of controlled reproduction (independent of whether a first or subsequent generation is produced) as well as younger specimens destined to be used for the same purpose

Bunsen burner

A gas burner consisting typically of a straight tube with small holes at the bottom where air enters and mixes with the gas to produce an intensely hot blue flame


A graduated glass tube with a small aperture and stopcock for delivering measured quantities of liquid or for measuring the liquid or gas received or discharged


A concretion usually of mineral salts around organic material found especially in hollow organs or ducts


A large container for liquids


The formation of partial vacuums in a liquid by a swiftly moving solid body (as a propeller) or by high - intensity sound waves


To subject to centrifugal action especially in a centrifuge

chelating agents

To combine with (a metal) so as to form a chelate ring


Any of a phylum or subphylum (Ciliophora) of ciliated protozoans (as paramecia)


An instrument or device for determining and specifying colors; specifically: one used for chemical analysis by comparison of a liquid's color with standard colors

ctenoid scales

Having the margin toothed (ctenoid scale); also: having or consisting of ctenoid scales (ctenoid fishes)

cycloid scales

Smooth scales with concentric lines of growth


A capsule formed about a minute organism going into a resting or spore stage


Dissolved oxygen

dead corners

Referred to area in tanks where there is no circulation of water and debris and waste accumulates

deionized water

To remove ions from (deionize water by ion exchange)


Living near, deposited on, or sinking to the bottom of the sea (demersal fish eggs)


Emitting a limited or insufficient amount of light


Having the basic chromosome number doubled

dry resting eggs

See cyst


A substance that when dissolved in a suitable solvent or when fused becomes an ionic conductor

Erlenmayer flask

Conical gas flask named after him

essential fatty acids

Fatty acid which cannot be synthesized by an organism and must be supplied in the diet to avoid a dietary deficiency

etiological agent

The primary organism responsible for changes in host animal, leading to disease


An organism composed of one or more cells containing visibly evident nuclei and organelles


Able to live in waters of a wide range of salinity


Tolerating a wide range of temperature (eurythermal animals)

extensive farming (aquaculture)

Any culture system that does not require supplemental feeding or direct energy input to support growth of the species under consideration


Finger size young fish

fish larvae

A fish from the beginning of the exogenous feeding to metamorphosis into juvenile. At a larval stage a fish differs greatly in appearance and behavior from a juvenile or an adult


A vial or a round long necked vessel for laboratory use

flow - through water system

Indicates hydraulic system in the hatchery in which water passes only once from inlet to outlet, without partial or total recirculation


Fibre Reinforced Polymer


Recently hatched fish which weighs less than 1 g or measures less than 2.5 cm total length


Any of a group of primitive plants lacking chlorophyll, reproducing through the production of spores, comprising single - celled or multinucleated organisms that live by decomposing and absorbing the organic material in which they grow, including moulds, rusts, mildews, smuts and mushrooms. Some kinds are parasitic on fishes


The process by which gametes are produced


The embryonic stage of development consisting of two layers of cells enclosing a sac - like central cavity with a pore at one end

gill raker

Bony, finger - like projections variously arranged along the anterior and often the posterior edges of the gill arches. They vary in number and shape, and are useful taxonomic characteristics


Refers to species with separate male and female sexes


A means of separating larger fish from smaller ones

Gram stain

A method for the differential staining of bacteria by treatment with a watery solution of iodine and the iodide of potassium after staining with a triphenylmethane dye (as crystal violet) - - called also Gram's method

green water

In hatcheries it refers to water with a high content of microscopic algae employed in larval rearing tanks


Place for artificial breeding, hatching and rearing through the early life stages of animals, finfish and shellfish in particular. Generally, in pisciculture, hatchery and nursery are closely associated. On the contrary, in conchyliculture, specific nurseries are common, where larvae produced in hatcheries are grown until ready for stocking in fattening areas

head loss

The loss of pressure in a flow system measured using a length parameter (i.e. inches of water, inches of mercury)


Having both male and female sexual characteristics and or/organs

hosha (= howash)

Low - lying areas from 2 to 6 ha in size enclosed by small dykes, in the Nile delta, in coastal regions and in coastal lakes of Egypt; following the increase of the drainage discharge from the Nile irrigation systems, the water table rises, fills the howash and natural stocking takes place; artificial stocking and supplementary feeding are optional; harvesting by complete drainage takes place in winter when water discharge rates are reduced


Highly Unsaturated Fatty Acids

hydraulic slope

Difference in hydraulic head over some flow path length

induced spawning

Egg - laying brought about by manipulation of the environment or treatment of the animal, for example, temperature and fertility cycle, osmotic shock, UV irradiation of water, hormone injections

intensive rearing

Production systems which are dependent on nutritionally complete diets added to the system, either in the form of fresh or frozen fish (freshwater or marine) or formulated diets, usually in dry pellet form


abnormal backward curvature of the spine

latency period

The time that elapses between a stimulus and the response to it

lateral line

Sense organs of fish and amphibians; believed to detect pressure changes in the water

live feeds

The term live feed can be used to describe either naturally occurring animals (although this is usually referred to within the broad band of productivity) or animals which are produced (usually under artificial, controlled conditions) for feeding larval stages of farmed fish, crustaceans and bivalves. The types of live feed used include rotifers, Artemia, algae and copepods

log - phase

Referred to bacterial or algal growth introduced in fresh media. It is the population growth phase in which binary division occurs. This phase of growth is called logarithmic or exponential because the rate of increase in cell number is a multiplicative function of cell number. This can be seen in a graph of cell number versus time where cell numbers increase at ever increasing rates with time or generation; that is, the rate of increase is a function of absolute cell number such that the more cells present, the faster the population of cells increases in size (at least, during log phase)


Rope suspended by buoys from which are attached ropes which hang down (drop line) to hold cages, clusters, baskets or lantern nets of shellfish. May be held at the water surface or at a deeper depth (subsurface or bottom longline)


abnormal curvature of the spine forward


In the Rotifers a hard protective case or shell

Lugol solution

Solution based on potassium iodide and iodine. See Annex 7 (Vol 1) for preparation


Unit of illumination equal to the direct illumination on a surface that is everywhere one meter from a uniform point source of one candle intensity or equal to one lumen per square meter


The pharynx of a rotifer. It usually contains four horny pieces. The two central ones form the incus,against which the mallei, or lateral ones work so as to crush the food

meiotic divisions

Reductive division (two successive divisions) of a nucleus following one single replication of the chromosomes, so that the resulting four nuclei are haploid. In animals, it occurs during gamete formation


Chromatophores (large pigment cells of fish, amphibia, reptiles and many invertebrates) which contain melanin. Short term color changes are brought about by an active redistribution of the melanophores pigment containing organelles (melanosomes)


Late nauplius stage of crustaceans, with more than three pairs of limbs present but no functional thoracic limbs


Any of a group (Metazoa) that comprises all animals having the body composed of cells differentiated into tissues and organs and usually a digestive cavity lined with specialized cells


Microscopic photosynthetic (chlorophyll - containing) organisms that are usually single cells, these aquatic forms are often referred to as phytoplankton, but they can also be benthic microalgae present in the bottom sediment


Periodic shedding of the cuticle in arthropods


measurement of external form


A globular solid mass of blastomeres formed by cleavage of a zygote that typically precedes the blastula


Earliest larval stage of a crustacean; it exhibits the simplest type of head region with three pairs of appendages, uniramous first antennae, biramous second antennae and mandibles. Although the nauplius larva is typical, it does not appear in all crustaceans. It is common in lower forms, but in many of the higher forms it occurs during development in the egg, and the young are hatched as differentiated and more advanced larvae


Elongated, cylindrical, unsegmented worm; includes a number of plant and human parasites

nutritional boosters

Feed additives intended to provide additional energy to feed or to optimize the balance of ingredients to adjust the feed to the nutritional requirements of the species farmed.


Cell which develops into an ovum


Cellular development that leads to the formation of an ovum


A descendant of a primordial germ cell that gives rise to oocytes


the covering of the gills of a fish

osmotic regulation

movement of a solvent through a semi permeable membrane (as of a living cell) into a solution of higher solute concentration that tends to equalize the concentrations of solute on the two sides of the membrane


development and formation of bone

ovarian atresia

Absence or disappearance of an anatomical part (as an ovarian follicle) by degeneration


Producing eggs that are fertilized, develop, and hatch outside the female body


Producing eggs, usually with much yolk, that are fertilized internally. Little or no nourishment is furnished by the mother during development; hatching may occur before or after expulsion

palatine bones

Bones forming the roof of the mouth separating the mouth from the nasal cavity


The ventral transverse, or capitular, process of a vertebra

Pasteur pipette

A small piece of apparatus which typically consists of a narrow tube into which fluid is drawn by suction (as for dispensing or measurement) and retained by closing the upper end


Infection caused by the bacteria genus Pasteurella

pelletized dry feed

Compounded feed formed by pressing and forcing feed ingredients through die openings by a mechanical process


An enzyme that hydrolyzes simple peptides or their derivatives

Petri dish

A small shallow dish of thin glass or plastic with a loose cover used especially for cultures in bacteriology


A term used to describe the hydrogen ion activity of a solution. The pH of pure water is 7 and is referred to as neutral. A solution of pH less than 7 is said to be acid whereas a solution of pH above 7 is said to be alkaline

photoperiod control

Technique used to anticipate or retard breeding based on the control of the duration of time in a given day during which the culture organisms are exposed to light and dark. The light source can be natural or artificial


Synthesis by plant cells of organic compounds (mainly carbohydrates), in the presence of light, from carbon dioxide and water, with simultaneous production of oxygen. Conversion of light energy into chemical energy


Type of fish species having the gas bladder closed, with no connection to the gut


Minute plants suspended in water with little or no capability of controlling their position in the water mass; frequently referred to as microalgae (the plant component of plankton


Measuring instrument consisting of a graduated glass tube used to measure or transfer precise volumes of a liquid by drawing the liquid up into the tube


Parts per million


Parts per thousand


A boomerang - shaped bone whose edges form the posterior and lower margins of the cheek region; the most anterior of the bones comprising the gill cover


Poly Unsaturated Fatty Acids

purse seine

A large seine designed to be set by two boats around a school of fish and so arranged that after the ends have been brought together the bottom can be closed


Polyvinil Chloride


An instrument to measure indices of refraction (directly related to salinity levels)


The condition of being filled up or overcrowded

roughness coefficient

Designated by "N" in Manning’s flow equation, the roughness coefficient is an expression of the resistance to flow of a surface such as the bed or bank of a stream


In aquaculture: an expression for the concentration of soluble minerals (often restricted to salts of the alkali metals or of magnesium) and chlorides in water; usually expressed as parts per thousand (ppt)


A group of fish swimming together


a lateral curvature of the spine

screw clamp

A device designed to bind or constrict or to press two or more parts together so as to hold them firmly


Floating device where air is blown at low pressure tangentially to the water surface to trap and continuously remove floating debris and oily surface layer from the air/water interface in larval rearing tanks of industrial hatcheries. The fish larvae may thus easily gulp air and inflate their swimbladder

solenoid (valve)

A coil of wire usually in cylindrical form that when carrying a current acts like a magnet so that a movable core is drawn into the coil when a current flows and that is used especially as a switch or control for a mechanical device (as a valve)


The quantitative relationship between two or more substances especially in processes involving physical or chemical change


Organ (bladder) containing gas, present in the roof of the abdominal cavity in bony fish. It allows the specific gravity of the fish to vary in order to match the depth at which the fish is swimming or resting

tank meniscus

The curved upper surface of a column of liquid


Any of a major taxon (class Osteichthyes or superclass Teleostomi) comprising fishes (as a sturgeon, salmon, marlin, or ocean sunfish) with a bony rather than a cartilaginous skeleton


Refers to the daily temperature cycle to which a species is subject

trace minerals

Nutrient elements essential for the life and growth of an organism, but needed in only very small quantities or amounts

trawl net

A large conical net dragged along the sea bottom in gathering fish or other marine life


Italian term referring to fish farming in embanked or fenced lagoons found principally on the northwestern Adriatic coast of Italy, which are subject to a considerable control of water levels, salinity and temperature


Infection caused by Vibriogenus bacteria


An organic compound occurring in minute amounts in foods and essential for numerous metabolic reactions


Yolk formation


Total nutritive reserves incorporated into the egg cytoplasm

vomerine teeth

Teeth on a bone of the skull of most vertebrates that is situated below the ethmoid region

zona radiata

A thickened, rather complex egg membrane of teleost fishes, which often has a radiate appearance. It is formed at the surface of the egg by the ooplasm, or the ooplasm and the follicle cells and hence should be regarded as a true vitelline membrane. May be overlain by the chorion


The animal component of plankton

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