bioacoustics 04jan 7 - 31 Jan 2004 There were several types of bioacoustic transects conducted with a towed 120 kHz transducer (BioSonics) during the annual January cruise. A. at ship speed 2.0 to 2.5 kts 1) Discrete acoustic transects were done at each station simultaneously with the 2-M and 1-M net tows, for the 200.*, 300.*, 400.*, 500.* and 600.* cardinal lines, and the inshore stations. 2) Palmer nearshore transect A-E and F-J during the cruise. B. At ship speed 4.0 to 4.5 kts Continuous acoustic transects simultaneously with seabird observations over high density grid 1 as established in Jan 1995. 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 fourteen variables in the event_bld_list are: Event.number Start.time (GMT) End.time (GMT) Start.Date (mmddyy GMT) TVG-Corr Flag (correct for 40logR operation if done) Palmer LTER grid location (xxx.yyy where xxx is the alongshore transect line id and yyy is the on/offshore station id) Start.Latitude (¡S) Start.Longitude (¡W) End.Latitude (¡S) End.Longitude (¡W) File name 1 ... File names 4 if transect is longer than 30 min 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. There were a total of 150 bioacoustic events (computer files exist for 189 events) in 04Jan. Station spacing was 20 km along the cardinal lines. The high density (HD1) 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 started on one day completed on Jan 15, 2003. The Palmer nearshore transect (Pal J-F and on to -E) was done at the beginning of the cruise only. 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 DT-X digital echosounder connected to a downward looking 120 kHz split-beam transducer which was deployed with a tow body several meters below the surface. The towbody was deployed with the research vessel Laurence M. Gould. The DT-X series simplifies the collection of data, and shifts as many decisions as possible from the data collection environment to data processing. For example, time-varied gain (TVG) and bottom tracking are applied during analysis. The raw digital data is collected to the computer's hard disk drive. Data is collected with the following set up: ¥ Operating mode: single beam for survey, split-beam for in situ calibration ¥ Acoustic mode: active for survey, passive when checking for background noise ¥ Data collection parameters: a) Start Range ___1 m b) End Range -300 m c) Threshold Level (dB) -100 Transmit Power Ð High Absorption Coefficient (DTX) NOT checked d) Threshold Mode: linear e) Environmental Parameters: temperature and salinity set to get speed of sound of 1440 m/s as in previous years ¥ pulse control a) Pulse Rate: 1 pps b) Pulse Duration: 0.4 ms (2) archival process Data are transmitted from the DT-X surface unit with RTP (real-time transport protocol) and are stored directly to the computer hard drive. The RTP data stream is also read by the Visual Acquisition and displayed as an echogram and oscilloscope output on the computer screen. Once the time limit for a file has been reached, or the file is manually closed as the end of a transect, VISACQ closes the RTP file, opens and names the next RTP file, and then converts the newly closed RTP data into a BioSonics DT4 file format. The DT4 file format allows the data files to be processed by both BioSonics and 3rd party software. Data files are named LTRyyyymmdd_hhmmss, with the year (yyyy), month (mm), day (dd), hour (hh), minute (mm) and second (ss) synched with the computer clock. There are three files for each transect: - *.RTP - *.DT4 - *.nme, the gps location file as linked to the ship's gps (3) calibration of the system was done by BioSonics ( Seattle, WA) in a tank at ambient temperature. Calibration was done for the deck and tow cable combination. Calibrations were done before and after the cruise, 7 Oct 2003 and xxxx 2004. Three in situ calibrations were also conducted on 29 Nov 2003 on board the LM Gould, with a tungsten calibration sphere suspended ~ 6 m and directly below the transducer, and a separate configuration file. 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. The high density grid was run continuously and at a higher speed to accommodate the requirements of the seabird observers. The high density grid is conducted during presumed peak penguin chick growth periods. Antarctic krill are usually the dominant sound scatterer in the Palmer LTER region, but other euphausiid species, salps and pteropods also occur over much of the mesoscale grid. bioacoustics, antarctic krill, palmer lter 1) event_bld_list for both the data and the noise files ascii, space delimited (number of columns)! 04jan and identifying information rows with column headers and the units of the parameter data follow 3) binary data files for each transect The event_bld_list is in: ~lter/data/04jan/bioacoustics Velella on the MSILTER Apple talk network The *RTP, nme and DT4 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_listdata event_listnoise (2) rawdata/ The binary data files (3) for each transect are named by the prefix LTR and the date and time stamp, with the appendix for the type of file, e.g. RTP, DT4 and nme. The passive noise and calibration files have prefixes NOI and CAL, with the same date and time stamp. Robin M. Ross, Langdon B. Quetin none Robin M. Ross, Langdon B. Quetin R.Ross, B. Cheng, A. Kaiser, S. Talley, R. Cadiz, J. Watts RM Ross and LB Quetin RM Ross and team RM Ross 12 November 2006 BioSonics (2002) BioSonics DT-X and BioSonics DE-X Digital Echosounders and Visual Acquisition 5.0 Software User's Guide Version 1.1. 61 p 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. Lascara, CM, EE Hofmann, RM Ross, LB Quetin (1999) Seasonal variability in the distribution of Antarctic krill, Euphausia superba, west of the Antarctic Peninsula. Deep-Sea Res. 46: 951-984. 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.