GLOSSARY 493 



Portal of Exit The pathway by which pathogens or parasites leave or 

 are shed by the host. 



Posttreatment Treatment of hatchery wastewater before it is discharged 

 into the receiving water (pollution abatement). 



Pox A disease sign in which eruptive lesions are observed primarily on 

 the skin and mucous membranes. 



Pox Disease A common disease of freshwater fishes, primarily minnows, 

 characterized by small, flat epithelial growths and caused by a virus as 

 yet unidentified. Synonyms: carp pox; papilloma. 



Pretreatment Treatment of water before it enters the hatchery. 



Prevention, Disease Steps taken to stop a disease outbreak before it 

 occurs; may include environmental manipulation, immunization, 

 administration of drugs, etc. 



Progeny Offspring. 



Progeny Test A test of the value of an individual based on the perform- 

 ance of its offspring produced in some definite system of mating. 



Prophylactic Activity or agent that prevents the occurrence of disease. 



Protein Any of the numerous naturally occurring complex combinations 

 of amino acids that contain the elements carbon, hydrogen, nitrogen, 

 oxygen and occasionally sulfur, phosphorus or other elements. 



Protozoa The phylum of mostly microscopic animals made up of a sin- 

 gle cell or a group of more or less identical cells and living chiefly in 

 water; includes many parasitic forms. 



Pseudobranch The remnant of the first gill arch that often does not 

 have a respiratory function and is thought to be involved in hormone 

 activation or secretion. 



Pseudomonas Septicemia A hemorrhagic, septicemic disease of fishes 

 caused by infection of a member of the genus Pseudomonas. This is a 

 stress- mediated disease that usually occurs as a generalized septicemia. 

 See Bacterial Hemorrhagic Septicemia. 



Pyloric Cecum See Cecum. 



Pyridoxine (Vitamin B,,) One of the B-complex vitamins involved in fat 

 metabolism, but playing a more important role in protein metabo- 

 lism. As a result, carnivorous fish have stringent requirements for this 

 vitamin. 



Quaternary Ammonium Compounds Several of the cationic surface- 

 active agents and germicides, each with a quaternary ammonium 

 structure. They are bactericidal but will not kill external parasites of 

 fish. Generally, they are used for controlling external bacterial patho- 

 gens and disinfecting hatching equipment. 



Radii of Scale Lines on the proximal part of a scale, radiating from 

 near center to the edge. 



