5 Mar 1974
- waterbody:North Atlantic OceanGrand Turk Island; U.S. Naval Facility
NOTES: Notes on tape: "Time 0307 Zulu 06Mar1974" [MLNS notes: This should be 2207 the previous date. Low level thumps throughout, with several louder single thumps, or pulses, interspersed.] Notes from analysis log: "Cassette number side up, rewind. Ambient level low. Humpbacks: Pos.; Need for further analysis: No. Notes: At 219, hear bits of humpback calling, weak. At 468 still hear bits of Hump in background. Minke: Pos.; No. Heard: 2-3; No. Trains: 16+; Need for further analysis: Yes, the slow low job 052, Notes: At 005 a thump train, strong one. At 052 is a _good_ strong _slow thump train_ as opposed to the normal one. At 134 is a normal moderate level train. At 287 a strong one appears, at 304 a different one (Pitch shows) again at 334 & 342 (slow ones), at 435 a moderate level thump train again at 468, again at 518, again at 538 strong one, again 568. At 580 the strong slow train! At 593 a second one shows, at 651 strong train, at 712. Best showing of _Slow THUMPER_ here."
[Notes from analysis log for all tapes in the GRANDTURKS series: "Six half-hour background recording samples on selected days for a period of 53 days... to detect the arrival and departure of the Humpback whales (via sounds) for the season in the Caribbean Sea, Mouchier, Navidad and Silver Banks...There are indications that recordings used a 420Hz Low Pass Filter. Recording equipment used was a Realistic model CTR-19. Cassette recorder operating on 110VAC, Freq 60-10,000Ha.. The Realistic recorder is poor recording frequencies below 60Hz as evidenced by spec sheet and sonograms. There is 120 & 180Hz electrical interference 'splatter' on some tapes. In certain cases when the ambient is low, the gain of the systems are raised hence we have heavy interference masking wanted signals. This could be caused by a fluorescent light fixture near the recording system? I doubt that it is in the hydrophone pre-amp network." See analysis log for more details.] SEAOCEAN