trawl2m 91nov 12nov91-20nov91 Zooplankton and micronekton collected by 2-M metro trawl towed in the upper 120 m. The catch is used for: A. random samples (1) species composition and abundance for community composition and distribution (2) alternate scatterer abundances which is used to correct the acoustics biomass data taken at 120 kHz for scatterers other than antarctic krill (3) random sample of antarctic krill for length frequency and females with red thelycums (MF) which is subsequently preserved and selected females analyzed for physiological maturity stage (Cuzin-Roudy and Amsler, 1991), and B. selected specimens (4) the source of antarctic krill for PHYCONA (physiological condition of adults) over the entire spatial scale of the cruise, which includes instanteous growth rate experiments on board chemical composition and condition factor of adult krill There are two files that contain information on all trawls. (1) file: trawl_rec is a record of the trawl information for all trawls and the disposition of the catch event #, tow #, date, time begin (GMT), day/night, tow duration (min), LTER grid location, begin latitude, begin longitude, tow direction (heading), ship speed in knots, water depth (m), cloud cover (%), wind speed (kts), wind direction, gear (1-M or 2-M or 3-M trawls), tow type (oblique, live for krill for physiology only), target depth, volume filtered (m^3) as calculated, time-depth-recorder (TDR) depth indication, TDR tow duration, catch split (yes or no), organisms removed (yes or no), preserved sample (yes or no); instantaneous growth rate number for adults or juveniles if experiment conducted; number of samples frozen for chemical composition and condition factor determinations for individual and bulk adults, and individual and bulk juveniles; catch volume (ml) measured on live wet sample in graduated cylinder; volume preserved (ml) if catch was split or organisms removed from total catch before preservation ¥ Organisms removed means different things depending whether or not there was a split of the catch. Euphausia superba for physiology were removed before volumes were measured Thus if there was no split, organisms may have been removed for other purposes (experiments or chemistry for example), the preserved sample is therefore not a totally random sample and can only represent the community composition if the organisms removed are added back into the sample analysis. OR all rare organisms were removed before the split and preservation, for example, usually adult fish were frozen and large jellyfish tossed. (2) file: trwl_catch Catch information for all trawls, nd if no data, numbers if available, A if absent, P if present, L if many, * if present but no size information is available. Some taxonomic categories are divided by size (most euphausiids > or < 25 mm; salps, chaetognaths large and small). Parameters are: event #, tow #, LTER grid transect, LTER grid station, volume filtered (m^3), live volume of catch (ml), volume preserved (ml), sum of volumes of alternate scatterers (7 categories - Euphausia superba, Euphausia crystallorophias, Thysanoessa sp, salps, Limacina sp, siphonophores and amphipods, with numbers and volumes). Also included are Euphausia triacantha, Euphausia frigida, Clione (non shelled pteropods), copepods (only present or absent if noted), chaetognaths, silverfish adults and larvae, other fish adults and larvae. Tow numbers 6, 7 and 36 are not in this database as either the tow was aborted or the cod end bucket was broken so there was no possible catch. There are also multiple files generated by the analysis of the 2M trawl samples: (3) file: trwl2m_altscat This file contains information on the numbers and volumes derived from the analysis of the preserved samples of presumed alternate scatterers (7 categories). Volumes of the categories were either measured directly or calculated from numbers and assumed volumes per individuals. For Euphausia superba, volumes assumed depended on the size classes present and were estimated from the total length/wet weight relationship: juveniles 0.07 ml/individual; 25-30 mm 0.15 ml/individual; 30-35 mm 0.3 ml/individual; 35-40 0.4 ml/individual; 40-45 mm 0.65 ml/individual; 45-50 mm 1 ml/individual. Volume estimates for the other 6 categories: Thysanoessa sp 0.05 ml for > 25 mm individuals, 0.025 ml for < 25 mm individuals; salps 0.2 ml/individual as most of the salps present were small solitaries; Limacina 0.1 ml/individual; siphonophores always measured; amphipods 0.12 ml/individual; Euphausia crystallorophias measured. 21 # nov91 volume and numbers of alternate scatterers from 2M trawl, P=present, nd=no data Event number Tow number LTER grid transect number LTER grid station number Volume filtered (m^3) Total catch volume (ml) measured live Sum of volume (ml) of alternate scatterers measured preserved Euphausia superba number Euphausia superba volume (ml) Thysanoessa sp number Thysanoessa sp volume (ml) Salp number Salp volume (ml) Limacina (shelled pteropod) number Limacina (shelled pteropod) volume (ml) Siphonophore number Siphonophore volume (ml) Amphipod number Amphipod volume (ml) Euphausia crystallorophias number Euphausia crystallorophias volume (4) directory: trwl2m has two directories for the length, sex category and maturity stage data. These data come from measurement and sex identification of a random sample of at least 100 krill or the total catch. Variables are source of individual measured, sex category, maturity stage and total length (mm). Individuals removed from the catch for chemistry or experiments and that were measured are included in the raw data. Each data file is named for the event and tow number, for example, EV100T30.***. The first line for each file is the number of parameters plus identifying information such as study name, event number, LTER grid location, and data type. The raw data follows. Each tow has two files, one in each directory, one for all raw data and one for length data only. DIRECTORIES The data in krill_raw is not appropriate for length frequencies unless adjusted for the multiple splits and removals. See files in krill_lfhist for length frequency data, with number of individuals in each length bin as adjusted for the multiple splits and removals. (a) krill_raw, raw data for each event The first line of each file is the number of parameters (4) plus general information after the # sign. The parameters are: SOURCE - the source of the animal categorized or measured, i.e. the preserved sample or individuals removed from the catch before preservation for chemical composition or growth rate experiments SEX CATEGORY - the sex category of the animal Categories are: furcilia stages 1-6 (Fraser, 1936), juvenile (two pair of postero-lateral spines), subadult (one pair of postero-lateral spines, no secondary sexual characteristics), male (immature or mature petasma), female (immature or mature thelycum). Those individuals that cannot be staged are "?". MATURITY STAGE - indication of mature versus immature secondary sex characteristics, whether red thelycum, and physiological maturity stage for some tows. Physiological maturity stage is according to Cuzin-Roudy and Amsler, 1991. TOTAL LENGTH - total length from the tip of the rostrum to the end of the uropods (standard length 1) in mm. For small animals measurements are done under a dissecting microscope with an ocular micrometer. For some damaged individuals total length is calculated from equations relating either total length and telson length or total length and carapace length: - * in the maturity stage column indicates that length for < 24 mm individuals was calculated from the following equation: total length = 5.31*telson length - 2.729, r2=0.926 Data source for equation was the total lengths and telson lengths from the larval instanteous growth experiments #1,4 and 6 conducted in October and November of 1991. - ** next to the sex category indicates that length for 27.5 to 47.5 mm individuals was calculated from the following equation: total length = 2.757*carapace length + 2.813, r2= 0.926 Data source for equation was the total lengths and carapace lengths from events 100, 121 and 129 of the nov91 cruise: ¥ if the damage is too great and the individual cannot be measured but can be categorized, 99999 is placed in the total length column. (b) krill_lfhist contains the files for length frequency distributions A ***.LFHIST file is not generated for an event if there are less than 10 Euphausia superba in the catch. The first line of each file is the number of parameters (2) plus general information after the # sign. The parameters are: BIN - length bins by 0.5 mm, i.e. the length bin 9.0 refers to a total length interval of 9.0 to 9.49 mm. ADJUSTED FREQUENCY - number of individuals in that size bin, adjusted for splits; this is not the number of individuals measured, but the number for each length bin derived from the number of measured individuals in each length bin, and the proportion of the total catch represented by that individual. (1) file: trawl_rec volume filtered (meters cubed) = Net area * ((flow meter final reading - flow meter initial reading) * (26873/999999)) The flowmeter reading is recorded as 6 digits as the last digit of the 7 digits seen on the flowmeter is 0.1 revolution and is simply dropped. When the meter "turns over", i.e., goes past 999999 back through zero, a 1 is added in front on the meter reading. For example, if FM initial = 878361, and FM final = 052787, the FM final is really 1052787. (2) directory krill_lfhist The number of animals in a length bin is derived from the number of measured individuals in that bin multiplied by the split factor (pre- and post-preservation) and the ratio of categorized to measured for a size grouping. The 2M trawl is fished both (1) at standard intervals at stations spaced at 20 km intervals going offshore on the transect lines which are spaced at 100 km intervals alongshore, and (2) as a targetted tow to collect live krill for experiments. A. Collection (1) trawl specifications: * 2-M trawl is a Metro net, with a fixed frame 2-m on a side, and the bridle attachments in the middle of the side pieces of the frame; the mesh size for both the net and the codend is 500 um; (2) protocol for deployment: * TDR is attached to the top of the frame, and a flow meter (General Oceanics) is attached to side of the frame so it hangs in the middle of the net opening; snap clips are used for easy removal * tow is a double oblique tow to a standard depth of 120 m, water depth permitting. Wire out (m) and wire angle, measured from the stern, plus a wire angle chart is used to target the fishing depth of the net. This depth is verified by the TDR and the relationship between targetted depth and actual depth has been used to develop an empirical wire angle chart for this particular net/ship combination. The TDR depth is verified periodically by attaching it to the Bio-Optical Profiling System and comparing the BOPS depth and the TDR depth. * all information for the TRAWL RECORD for each tow is recorded on a data sheet; the TDR paper is taped to that sheet and the time and depth of the tow as measured by the TDR is recorded. B. Sample treatment (a) treatment of catch: The goal is (1) to preserve a sample to characterize the total catch, i.e., numbers and volumes of each type of organism, and (2) to preserve, freeze, or use subsamples of our targetted species for several purposes. * when the net comes on board the cod end is set gently into a large white tub (50 liters) filled one-third to one-half with cold seawater, then unclipped; if there are no krill the net is rinsed down with a hose, directly into the halibut tub; if there are krill, the air bubbles could affect their physiological condition so the cod end contents are poured gently into the tub, then the net is rinsed into the cod end and the contents poured into the tub * If the catch was large (> 300 ml), the total volume of the catch was measured with a graduated cylinder, and a random subsample of known volume preserved. If the sample was split then the subsample preserved had no zooplankton or krill removed. If the sample was not split, then the total catch includes the preserved sample and any animals used for either growth rate experiments or frozen for chemical composition. Catch volume as recorded was measured after animals were separated for physiological condition. he TRAWL CATCH LOG for each event contains the details of the catch processing and disposition of the catch (# and size of preserved jars and preservative (formalin or ethanol), # frozen and size of vial, # into IGR etc). (a) KRILL (b) FISH (c) SALPS euphausiids to species pteropods: to genera (Limacina and Clione) amphipods: T. gaudichaudii and all others chaetognaths: large ones counted, small ones noted ctenophores: to phyla siphonphores: to group (e) presence noted heavy phytoplankton copepods ¥ Length frequency information is taken for Euphausia superba only. Total length is standard length 1, or the length from the tip of the rostrum to the tip of the uropods excluding spines, measured with digital calipers. Volume is measured with a graduated cyclinder with small holes drilled in the bottom to let water drain. Tows are done at standard stations along the cardinal lines, i.e., the onshore/offshore resolution is 20 km, and alongshore is 100 km. This is the same spatial resolution as for other biological and physical data. The standard depth for this tow was set to correspond to the deepest depth at which krill schools have been observed in this region. The primary objective for the standard 2-M trawl collections is to verify the alternate scatterers for the acoustics. Targeted tows are for physiological condition of antarctic krill. Observations and catch processing information, and disposition of catch are recorded on three forms for each event: trawl record, trawl catch log, and krill catch length frequency & sex category. length frequency, sex category, physiological maturity, zooplankton community composition ascii, comma separated variable The first line contains the number of columns and some header information, each following line identifies each variable with units, and the data follows. online lter robins mac ~lter/lterdata/91nov/trawl2m/* also see ~lter/lterdata/91nov/trawlgen/trawl.lis,trawl.catch (1) directories krill_raw, and krill_lfhist data files are named EV**T**.raw or EV**T**.LFHIST, with the * standing for event and tow numbers (2) directory trawl_gen for all trawls has trawl_rec trawl_catch Robin M. Ross, Langdon B. Quetin none Robin M. Ross, Langdon B. Quetin Langdon B. Quetin, Tim Newberger, Cathy Lascara, Mark Talkovic, Vance Vredenberg K. Hacecky, J. Mahoney for 500.* and 600.* transect lines; T. Shaw and J. Squier for 700.* line. Robin M. Ross, K. Hacecky, T. Shaw Robin M. Ross Robin M. Ross November 4, 1994: krill_raw and krill_lfhist December 4, 1994: trwl2m_altscat, trwl_rec, trwl_catch December 4, 1994 trawl2m_info updated. 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. Anon. Key for the Identification of Antarctic Euphausiids. BIOMASS Handbook 5. Cuzin-Roudy, J, and M. O. Amsler. 1991. Ovarian development and sexual maturity staging in antarctic krill. J. Crustacean Biol. 11(2): 236-249. Spread sheets are set up to double check the split calculations and the allocation of the different individuals to the correct length bin and sex category. Raw data is scanned for length and sex category combinations that do not match historical data. Length frequency graphs are plotted and examined for outliers. 12/4/94: EV110T33, EV121T37, EV144T44.LFHIST corrected. Differences minor. Cathy M. Lascara, Old Dominion University On this cruise many samples were not preserved with enough perservative volume to animal volume. As a consequence a large number of individuals were damaged, and could not be measured, although they could be categorized as either small (< 24 mm) as belonging to the late furcilia, juvenile or subadult group, or large (> 24 mm) and usually either mature or immature adults. Because of the multiple uses and splits for many catches, the process for generating the length frequency data was complicated for this cruise. In subsequent cruises, the process has been streamlined and simplified.

Datafile Form V1.2 for describing a data file.