bioacoustics 97jan 11 Jan to 13 Feb 97 bioacoustic transect for Antarctic krill There were several types of bioacoustic transects conducted with a towed 120 kHz transducer (BioSonics) during the cruise. Discrete acoustic transects were done at each station simultaneously with net tows, at ~2.2 kts. Thus there are replicate transects at all cardinal stations. Continuous acoustic transects were conducted during three activities: the 3.7 and 10 km picket lines, the high density grid, and the spatial variance transects. The continuous transects were done at 4.5 kts. A. An event_bld.list gives details of time and location for all acoustic transects, with links to the rest of the data collected through the event number. The ten variables in the event- bld.list are: event.number Palmer.Grid-Line Palmer.Grid-Station Start.time (GMT) End.time (GMT) Start.Date (mmddyy GMT) Start.Latitude (degS) Start.Longitude (degW) End.Latitude (degS) End.Longitude (degW) For transects conducted simultaneously with net tows, the Palmer Grid location is the center of the transect. For continuous transects, the Palmer Grid location is the beginning of the segment of the transect. For the picket lines, PL3.7 and PL10 in the line column stand for picket line 3.7 and 10 , and the 30° segment is in the station column, i.e. 265- 295. For 7 other events, not standard stations, the Palmer Grid location is also the beginning of the transect: event#s 388, 493, 1099, 1107, 1109, 1130, 1132. B. The calibration files give the calibration constants: Variables are: BeamPatternFactor Rcvr1_G120logR Rcvr1_G140logR Rcvr2_G120logR Rcvr2_G140logR Rcvr3_G120logR SrcLevel_at0dB SrcLevel_at-3dB SrcLevel_at-6dB SrcLevel_at-10dB SrcLevel_at-13dB 20/40CrossoverPt There were a total of 309 acoustic files for 97jan. Two short (1.7-2 km) acoustic transects were conducted in conjunction with net tows at each Palmer LTER station occupied during a cruise. Stations were on the 600.*, 500.*, 400.*, 300.*, 200.* cardinal lines, inside Marguerite Bay, in Crystal Sound and Grandider Channel, and in Palmer Basin. Station spacing was 20 km along the cardinal lines. Picket lines follow a circle with a radius of 3.7 or 10 km and centered on Palmer Station; the individual segments are 30°. The PL3.7 with 7 segments was done three times, the PL10 with 6 segments twice. The high density (HD) foraging grid, 10 by 20 km with the longer distance moving offshore, is within the foraging range of the Adelie penguins nesting at Palmer Station. During the HD grid, 10 km transects spaced 2.5 km apart were run, connected by short 2.5 km transects.The HD grid was surveyed twice. Long continuous transects to investigate spatial variance were also done three times during this cruise: two onshore/offshore of about 200 km, and one alongshore on the inner shelf of about 150 km. The two on/offshore transects were at 550.* (27 segments) and 250.* (22 segments); the alongshore transect at *.030 to *.050 (18 segments). The Palmer LTER uses Biosonics equipment and software to collect hydroacoustic data, and to do the preliminary processing on board. (1) collection of data The acoustic system consists of a BioSonics Model 102 echo sounder connected to a downward looking 120 kHz transducer which was deployed with a tow body several meters below the surface. The towbody was deployed with the research vessel RV Polar Duke. The sounder was operated with a 20 log R (R = range in m) time-varied-gain (TVG) function to compensaate for one-way acoustic spreading loss. (2) archival process The analog voltage signals received by the echosounder are processed in the field through an interface tape unit which records a digitized version of each signal onto a digital audio tape (DAT) recorder. The DAT tapes can be replayed with the Biosonics Echo Signal Processing (ESP) software package for calculation of Sum Squared Voltage (SSV) data if a file is lost or if a different configuration file is desired. (3) primary processing of data: Echo integration of the returned acoustic energy (volts) was done with the BioSonics Model 221 Echo Signal Processor, and ESP version 3 on a Dec 486 computer on board. The system was configured to integrate voltage measurements over 2-m depth intervals and several pings. These integrated values were used to generate a two-dimensional (alongtrack, vertical) matrix of volume scattering data (VSD, m3 m-3) for each acoustic transect, according to algorithms described in Apprendix C of BioSonics. When in deep water (>200 m) data was collected without a bottom algorithm. In shallow water, a bottom algorithm was used to automatically separate the bottom and biotic signal. (4) calibration of the system was done by BioSonics ( Seattle, WA) in a tank at ambient temperature. The calibrations bracketing the use of the equipment were done in May 1996 and August 7 and September12, 1997. The calibration files done in Aug/Sep 1997 were closest in time to use of the equipment and are recommended for use. During 97Jan, the OldDeck/OldTow cable combination was used only for event104. The tow cable developed a break, and the OldDeck/NewTow cable combination was used for all subsequent transects. The Deck cables are 100' long, the Tow cables 218' long - New Deck (S/N#141-94-870) - New Tow (S/N#147-94-156) - Old Deck (S/N#141-92-740) - Old Tow (S/N#147-92-137) Acoustic transects on stations were conducted within 4 hours of the time other LTER data sets were collected. Each of these acoustic transects was matched with a net tow to allow identification of potential scatterers and the size distribution of Euphausia superba, the dominant scatterer. Antarctic krill are usually the dominant sound scatterer in the Palmer LTER region, but during 97jan salps were also present over much of the mesoscale grid. Test trials are not included. bioacoustics, antarctic krill, palmer lter 1) event_bld.list ascii, comma separated (number of columns)! 97jan and identifying information rows with column headers and the units of the parameter data follow 2) calibration files ascii, space delimited 3) VSD acoustic matrix for each event binary file with results from echo integration of the voltage returning to the echo sounder. the data stored is mean voltage squared for each depth strata and ping. The event_bld.list and calibration files are in: ~lter/data/97jan/bioacoustics Velella on the MSILTER Apple talk network The VSD files are stored on a hard disk off line until room is available on line. They may be accessed by contacting Karen Baker, data manager for the Palmer LTER. (1) event_bld.list (2) acoCalib.970912OldDeckOldTow; acoCalib.970807OldDeckNewTow files named: acoCalib.(date of calibration)(cable combination) (3) rawdata/(event#).dat the VSD acoustic matrix for each transect is named by the event. Robin M. Ross, Langdon B. Quetin none Robin M. Ross, Langdon B. Quetin RM Ross, JL Jones and team RM Ross, JL Jones and team JL Jones, RM Ross and team JLJones, RM Ross rawdata in May 1997 event_bld.list, acoCalib files and documentation 22 June 1999 BioSonics (1990) BioSonics Echo Signal Processor Operators Manual. BioSonics, Inc., Seattle, WA, 373 pp. Lascara (1996) Seasonal and mesoscale variability in the distribution of Antarctic krill, Euphausia superba, west of the Antarctic Peninsula. Ph. D. Thesis, Old Dominion University. 167 pp. Greene, C. H., T. K. Stanton, P. H. Wiebe and S. McClatchie (1991) Acoustic estimates of Antarctic krill. Nature 349: 110. Nero, R. W. and J. J. Magnuson (1989) Characterization of patches along transects using high resolution 70 kHz integrated acoustic data. Canadian Journal of Fisheries and Aquatic Sciences 46: 2056-2064. Wiebe, P. H., C. H. Greene, T. K. Stanton and J. Burczynski (1990) Sound scattering by live zooplankton and micronekton: empirical studies with a dual-beam acoustical system. Journal of Acoustical Society of America 88: 2346-2360.

Datafile Form V1.2 for describing a data file.