Fish Hatchery Management - fisheries & aquaculture

492 FISH HATCHERY MANAGEMENTPerivitelline Space Area between yolk and chorion of an egg whereembryo expansion occurs.Permanganate, Potassium KMnOa; strong oxidizing agent used as adisinfectant and to control external parasites.Petechia A minute rounded spot of hemorrhage on a surface, usuallypHless than one millimeter in diameter.An expression of the acid-base relationship designated as the logarithmof the reciprocal of the hydrogen-ion activity; the value of 7.0expresses neutral solutions; values decreasing below 7.0 representincreasing acidity; those increasing above 7.0 represent increasinglybasic solutions.Pharynx The cavity between the mouth and esophagus.Phenotype Appearance of an individual as contrasted with its geneticmakeup or genotype. Also used to designate a group of individualswith similar appearance but not necessarily identical genotypes.Photoperiod The number of daylight hours best suited to the growthand maturation of an organism.Photosynthesis The formation of carbohydrates from carbon dioxideand water that takes place in the chlorophyll-containing tissues ofplants exposed to light; oxygen is produced as a by-product.PhytoplanktonMinute plants suspended in water with little or no capabilityfor controlling their position in the water mass; frequentlyreferred to as algae.Pig Trough Sra Von Bayer Trough.Pigmentation Disposition of coloring matter in an organ or tissue.Pituitary Small endocrine organ located near the brain.Planting of Fish The act of releasing fish from a hatchery into aspecific lake or river. Synonyms: distribution; stocking.Plasma The fluid fraction of the blood, as distinguished from corpuscles.Plasma contains dissolved salts and proteins. Compare riiiri Serum.PoikilothermicPollutantthe environment.Having a body temperature that fluctuates with that ofA term referring to a wide range of toxic chemicals andorganic materials introduced into waterways from industrial plants andsewage wastes.PollutionThe addition of any substance not normally found in oroccurring in a material or ecosystem.PopulationA coexisting and interbreeding group of individuals of thesame species in a particular locality.Population Density The number of individuals of one population in agiven area or volume.Portal of Entryhost.The pathway by which pathogens or parasites enter the