26 Feb 1974
- waterbody:North Atlantic OceanGrand Turk Island; U.S. Naval Facility
NOTES: Notes on tape: "Time1030 Zulu." [MLNS notes: low level minke thumps throughout] Notes from analysis log: "Good tape, hump special recording. Cassette number side up - rewind. ambient level low - short break at 294 (restart?). Humpbacks: Pos.; No. Calling: 1; No. Full calls: 1-2; Need for further analysis: Yes. Notes: Have hump calling right off start of reel, has echoes is moderate close to xphone, is in early portion of call. At times animal overloads system - fair parts for continuous sonogram. At 439 hear long surf ratchet tehn back to start of a call ( has weak squawk sds heard) at 699 have a surf ratchet then he goes into new call. Minke: Pos.; No. Heard: 2; No. Trains: 10; Need for further analysis: No. Notes: at 090 a minke thump train shows, again at 132, again at 319, again at 477 (in distance), again at 494, a different one at 515, again 550, again at 633, again at 671, again at 729."
[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