DEVEIOPMEhfT AND OPERATION OF TELEVISION FOR STUDYING 

 FISH BEHAVIOR IN OTTER TRAWLS 



by 



John R. Clark, Robert Livingstone, Jr., and James M. 

 U. S. Fish and Wildlife Service 

 Woods Hole, Massachusetts 



Crossen 



ABSTRACT 



Underwater television equipment (Image Orthicon) used for studying 

 the behavior of fish in otter trawls is described. Development of the 

 equipment, including the television chain itself and the accessory 

 power source, lights, etc., plus some methods of using the equipment 

 are explained. Considerable attention is devoted to problems of opera- 

 tion, particularly to the difficulties in handling the camera cable. 



An extensive appendix gives in some detail the specifications of 

 the television equipment used. 



Underwater television was successfully 

 used for the first time in connection with 

 the Bikini atom bomb tests of 1947 (Schultz 

 1948). Since the Bikini tests, television 

 has been used for such purposes as searching 

 the ocean floor for sunken vessels and for 

 pEtrts of wrecked aircraft (Stamp 1953, Cross 

 1954), for making observations for marine 

 engineering projects (Barnes 1956), and for 

 investigating the biology and ecology of 

 fish and other animal populations (National 

 Research Council of Canada, 1953; Backus and 

 Barnes 1957; Barnes 1952, 1953, 1955; Cuer- 

 rier et al. 1953; and Taylor 1953). 



The operation of marine fishing gear 

 has also been studied with underwater tele- 

 vision. The U. S. Fish and Wildlife Service 

 and U. S. Navy Bureau of Ships conducted a 

 joint program to observe midwater trawls in 

 Florida waters during October <ind November 

 1954. Subsequently, television equipment 

 was used in Florida waters by the Fish and 

 Wildlife Service to study fish traps and 

 shrimp trawls (Sand 1955, Sand and McNeely 

 1956). The Fishery Research Board of Canada 

 with the National Research Council of Canada 

 used television equipment to study scallop 

 drags in the Bay of Funday (Cameron 1955). 



The present report describes televi- 

 sion equipment developed at the Woods Hole 

 Biological Laboratory of the U. S. Fish and 

 Wildlife Service for studying the behavior 

 of marine fish, principally haddock. This 

 equipment was designed specifically to study 

 the behavior of marine "groundf ish" in otter 

 trawls on the New England offshore banks. 



DESCRIPTION OF THE EQUIPMENT 



The Television Chain 



The complete Image Orthicon televi- 

 sion chain is shown in figure 1. For the 

 benefit of those interested in the detailed 

 electronic and mechanical chauracteristics 

 of our equipment, we have included specifi- 

 cations and camera detail photographs in an 

 Appendix. 



The equipment was designed to provide 

 maximum versatility. The proposed program 

 of research necessitated that a number of 

 specific requirements be included in the 

 design. Special provisions made to ensure 

 the fulfillment of each of these are con- 

 sidered in the following discussion. 



