leached into the water. 



Other possible attractants include current meter rotors (Walden and 

 Panicker, 1963), hydrophones, or any equipment which could contribute to 

 sound propagation, owing either to moving parts or to in-line sensor 

 housings larger in diameter than the cable. 



It has been speculated that shark attack on scuba divers could be 

 provoked by galvanic currents generated by dissimilar metals of the regu- 

 lator, tank, and backpack strap (Klimley, 1974). Similar currents may be 

 produced in cables when care isn't taken to maximize cathodic protection 

 of instrument cases or achieve electrical isolation of aluminum and 

 stainless steel hardware (Morey, 1973). The importance of this requires 

 further clarification. However, as discussed previously, those elasmo- 

 branchs investigated have demonstrated great sensitivity to weak electric 

 fields. 



c. Conclusions and Recommendations 



1) Moored systems for the collection of oceanographic, meteorological, 

 and surveillance data are susceptible to damage or loss owing to 

 biting or slashing by fishes, including sharks. 



2) The extent and seriousness of the problem cannot be determined from 

 presently available evidence, although "fishbite" incidents are 

 apparently more common in tropical Atlantic waters. 



3) A central office (probably in the Naval Oceanographic Office) 

 should be established for collection and study of reports of 

 fishbite incidents, and users of moored systems should be informed 

 of the existence of such an office. Information provided to such 

 an office would permit determination of the identity of the 

 perpetrators of such "attacks" as well as the geographical and 

 seasonal occurrence of fishbite incidents. 



4) Further investigations are needed to understand the reasons for 

 the apparent attraction of sharks and other fishes to mooring 

 lines and cables. 



5) Information derived as a result of the above recommendations 



can be used to help develope more effective and practical mooring 

 lines and cables. 



36 



