OCEANOGRAPHY 173 



With your permission, gentlemen, I would like to exhibit a chart 

 that will save many words. 



Essentially this is an artist's depiction of some of the Navy's in- 

 terests in the field of hydrobiolocr>^ First, imder the objective of con- 

 trol of marine plants and animals that interfere with efficient naval 

 operations : Marine biological deterioration and fouling includes not 

 only the classic problems of deterioration of waterfront structures, the 

 fouling of ships" bottoms, and the breakdown of cordage, but also some 

 of the more specialized problems, such as the fouling of moored mine 

 cables, the deterioration of bottom mines and the fouling of tranducer 

 domes and hydrophones. 



Another aspect of our interest in control is related to the problem of 

 biological interference with underwater detection and communication 

 by acoustic means. 



Very frequently, organisms ranging in size from a few millimeters 

 to many feet may interfere with the propagation of acoustic enero-ies 

 imder water. They may show up as false acoustic targets quite similar 

 in appearance to targets of operational significance. This has been 

 and continues to be a problem of concern to submariners as well iis to 

 those groups concerned with antisubmarine warfare. 



Also, many types of marine animals are sound producers. Their 

 sounds may obscure sounds of operational significance or frequently 

 these somids may be confused with somids of propellers, engines, or 

 other types of equipment. This is a continuing problem. 



False targets are a special type of biological interference. Large 

 marine animals such as whales or porpoises or sharks may be confused 

 by the sonar man, unless he is very skilled, with sonar signals from 

 submarines or other types of ships. 



Another problem of control in the field of hydrobiology deals with 

 the protection of underwater swimmers and other persomiel against 

 poisonous, venomous, and carniverous marine animals. There is also 

 the need to protect the underwater swimmer against marine bacteria 

 and fungi, some of which cause acute infections in swimmere. Con- 

 trol includes, of course, the continuing problem of pei-sonnel protection 

 against sharks and some of the other carniverous animals. A small 

 but significant part of the hydrobiologV' program is devoted to re- 

 search leading to the development of more etl'ective shark repellents. 



Closely associated is the problem of ichthyotoxism. Many fishes of 

 commercial as well as sports interest ordinarily considered edible, 

 sometimes, in certain parts of the world, become toxic to man. This is 

 a basic ecological and biochemical problem that still needs to be solved. 

 It has been and still is of concern to the Xavy. For example, during 

 World War II in the Pacific theater of operations. Navy persomiel as 

 well as other service personnel and civilian populations were in part 

 dependent upon local fishery resources to sustaui themselves. They 

 found that some of the fishes which Avere considered to be edible, at 

 certain times of the year became toxic. 



I wish to say parenthetically at this time that what I am presenting 

 now is completely unclassified but there are a number of classified 

 aspects to this program and at your pleasure I would be happy to pre- 

 sent them to you. 



Another problem in control of hydrobiological pests, is concerned 

 with the problem of marine bioluminescence. 



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