23 Dec 1973
- waterbody:North Atlantic OceanGrand Turk Island; U.S. Naval Facility
NOTES: Notes on tape: "Time 0320 Zulu 24Dec1973." [This should mean 2220 local time 23Dec1973. 18Dec2003 CB] Notes from analysis log: "1st indication Humpbacks. Cassette number side down, rewind. ambient background level moderate - ship traffic in background is bothering early part of recording. Humpback: Need for further analysis: No. Notes: At 125, question a very distant whh-up portion of a hump call. Minke: Pos.; No. Heard: 2? No. Trains: 9; Need for further analysis: Yes Yes Yes (254) + (512). Notes: At 075, a moderate level thump train heard. Again at 108 moderate level slightly longer thump train. Again at 254 moderate level slightly longer thump train, has nice change - just about like one on TRI 22-14 reel. Best one example so far - real long duration. At 429 have a moderate level thump train. At 512 have a strong level thump train, long one, again at 615. Again at 649 only weaker now, then 676 a stronger (closer) one. Indications are that there are at least 2 different ones here, one closer to us than the other (see when doing complete analysis) Again at 759 a weak thump train."
[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