The bottom contours shown in the figure were obtained with 

 R/V GERDA on June 12 and 13, 1960. ^ The ship's position was obtained 

 from radar range and bearing observations on the Bimini shore line. 

 The contours on Figure 14, have been shifted 375 yards to the west of 

 corresponding contours shown in the referenced memorandum. The shift 

 was made to bring the contours into line with the range and depth 

 observations that were made when the cable was installed. The resulting 

 profile along the direction of the cable path (289°T) is shown in 

 Figure 15. It is believed that the new positions of the contours, 

 which were shifted as a group, are reasonably good representations of 

 depth versus range and bearing frxim a mid-point on the shore line of 

 the Lerner Marine Laboratory property. 



8 . Preliminary Results . 



(a) Marine Animal Sounds 



It was possible to obtain useful, sustained recordings 

 beginning with the second week in February, 1961. Prior to this date, 

 cursory observations indicated overloading due to what appeared to be 

 direct contact with the shallow water hydrophone. Two divers descended 

 to the hydrophone, took movies of the area, and covered the cable and 

 the hydrophone with sand. The movies revealed that a small fish of the 

 family Labridae was making direct contact with the protective cage of 

 the hydrophone. With the aid of the movies it was possible to identify 

 the presence of other fish in close proximity to the hydrophone. These 

 were members of the Carangidae, Seriola sp., and a single grunt, Haemulon 

 album. Using skin diving techniques, approximately 35 species of teleosts 

 and three species of elasmobranchs were noted in the area which is land- 

 ward of the shallow water hydrophone. It was in this general area that 

 portable listening gear and glass bottom buckets were used to hear and 

 see several species of reef fishes . 



Under the present sampling program, sustained recordings are 

 being made for 48 hours duration. Between recordings three days are 

 scheduled for monitoring and for adjustments in the system. Since a 

 two track recorder is being used, it is possible to record and monitor 

 Channel A and Channel B (shallow and deep water hydrophones respectively) 

 at the same time. Monitoring is usually done at a playback speed of 

 eight times the normal recording speed of 1 7/8 inches a second. 



The sounds are grouped into categories on the basis of 

 similarity of aural characteristics. The names given the catejgories 



Cruise Report °- Cruise G-6015, R. Dann, September 7, 1960 



