trawlgen 98jan.a 21jan98-23Jan98 Macrozooplankton community abundance and composition from acoustic tow Target tows to verify acoustic targets seen on the acoustic trace, done with Rubber Duke (Mark V zodiac outfitted with winch and A-frame) following the Abel J. One file was generated from these trawling activities. No detailed catch log was kept. trawl.list is a record of the trawl information for all trawls (25 variables): event.number tow.number Palmer LTER grid.line Palmer LTER grid.station GMTtime.begin(hr) GMTtime.begin(min) GMTtime.end(hr) GMTtime.end(min) day(D) or night(N) tow.duration(min) julian.day date.mm date.dd begin.latitude begin.longitude end.latitude end.longitude %cloud.cover tow.type(std obl=standard oblique, i.e. to standard depth; shal obl=shallow oblique; target=aim.for.aggregation; abort = did not complete; bottom.trawl = hit bottom) volume.filtered(m3)(General Oceanics flow meter#13583) catch split? Y=yes; N=no organisms removed: Y=yes; N=no total catch volume TL/MF-number of krill measured comments includes size of krill; whether or not there was a catch; depth layer targeted. The meaning of 'organisms removed' depends on whether or not there was a split of the catch. If there was no split, organisms were removed for other purposes (experiments or chemistry for example) so the preserved sample is not a totally random sample; the preserved sample represents the community composition only if the organisms removed are added back into the sample analysis. If the catch was split, often all rare organisms were removed before the split and preservation, for example, fish larvae, ctenophores or tomopterid worms. Sometimes either all krill or all salps were removed before the remaining samples was split. trawl.list & trawl.catch - volume filtered (meters cubed) = Net area * ((flow meter final reading - flow meter initial reading) * (26873/999999)) Trawling was done within the 50 km radius of the Adelie penguin rookeries near Palmer to verify targets. (1) trawl specifications: -the 1-m ring net is a fixed frame 1-m diameter; the mesh size for the net is 333 µm and the codend is 335 µm; (2) protocol for deployment: -a flow meter (General Oceanics) was attached to side of the frame so it hangs in the middle of the net opening; snap clips were used for easy removal; this was only used for 3 tows -the tows were oblique to targetted depth (3) treatment of catch: All fish larvae are removed and immediately preserved in 95-100% ethanol in 20 ml scintillation or 7 ml glass vials. The fish larvae are counted and identified on board if possible. A subsample of the Antarctic krill in the catch were measured, and categorized as either MF (mature female with red thelycum) or 'other'. The remainder of the catch was tossed. Tows were done to verify targets. Observations and catch processing information, and disposition of catch are recorded on two forms for each event: trawl record, trawl catch log. For this leg, the information on the trawl record and trawl catch log for each event for the entire cruise is summarized in one files: trawl.list.a. Antarctic krill from these catches were used for 5 total length/mature female determinations. zooplankton community composition, Southern Ocean, macrozooplankton ascii The first line is the number of columns followed by ! and the study name. Each subsequent line identifies the variable with units. Data follows in comma separated variable format. ~lter/~lterdata/98jana/trawlgen/* Velella on the MSILTER Apple network trawl.list Robin M. Ross, Langdon B. Quetin none Robin M. Ross and Langdon B. Quetin Marine Science Institute, UCSB, Santa Barbara, CA 93106 (805) 893-2096 robin@crseo.ucsb.edu or langdon@crseo.ucsb.edu LBQuetin, CT Shaw, D Conlin, K. Grimm, J. Kneebone. On board sample analysis by above. JL Jones, RM Ross RM Ross responsible for quality control of data sets. RM Ross 2 June 2000 Keys used to identify species: Kellerman, A. (ed.). 1989. Identification key and catalogue of larval Antarctic fishes. BIOMASS Scientific SEries No. 10. Gon, O., and P.C. Heemstra (eds.). 1990. Fishes of the Southern Ocean. J.L.B. Smith Institute of Ichthyology, Grahamstown, 462 pp. 12 pls. FAO Southern Ocean identification guides Makarov, R. Larval development of the antarctic euphausiids. BIOMASS Handbook No. 3. SCAR/SCOR/IABO/ACMRR, Group of specialists on living resources on the southern Oceans. Mauchline, J. Key for the identificaiton of antarctic euphausiids. BIOMASS Handbook No. 5. SCAR/SCOR/IABO/ACMRR, Group of specialists on living resources on the southern Oceans. Trawl information has been checked once against original records, and against the event log.

Datafile Form V1.2 for describing a data file.