trawl2m mar93 28mar93-12may93 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 the 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 *total length and wet weight relationships (see TL_WWT.info) There are multiple files/directories generated from the analysis of the 2-M trawls (1) file: trawl_rec is a record of the trawl information for all trawls, including the 2-M trawl event #, tow #, date, time begin (GMT), time end (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 midwater trawls), tow type (oblique to standard depth, targetted tow or oblique to shallower depth because the bottom depth is shallow), target depth, wire out, wire angle, wire rate out (m/s), time-depth-recorder (TDR) depth indication, TDR tow duration, catch split? (yes or no), organisms removed? (yes or no); volume of catch (ml), volume preserved (ml), number of krill, volume of krill, number of salps, volume of salps, and number of silverfish (larvae and adults) Organisms removed means different things depending whether or not there was a split of the catch. If there was no split, organisms may have been removed for other purposes (experiments or chemistry for example) so the preserved sample is not a totally random sample and therefore 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, all silverfish larvae. OR salps were counted, a volume taken and only representative individuals preserved (the remainder thrown away). (2) length frequency and maturity stage data Information on individual krill is recorded in files named for the event and tow number when there are > 10 E. superba in a catch. Data from the random sample of 100 krill measured and inspected for red thelycums on board is in EV**T**.raw. Variables are source of individual (fresh, preserved sample, growth experiment), total length (mm) and MF (mature female with red thelycum). (1) volume filtered in file: trawl_rec For from flowmeter hung in center of net opening volume filtered (meters cubed) = Net area * ((flow meter final reading - flow meter initial reading) * (26873/999999))] For 14 of the 2-M net tows, the volume filtered was calculated from the time fishing and the relationship between time fishing and volume derived from the mar93 data set (n=106): 2M_TRWL volume filtered (m^3) = 272.1*time fishing + 375.4, r^2=0.804 Volume calculated from this equation were for: events 20 through 105 (n=10), the flowmeterrr in use was not working properly; events 465 and 694 no flowmeter readings were available; events 546 and 752, the volume filtered appeared to be an overestimate by a factor of 2 or 3 from an inspection of a graph of time fishing versus volume filtered. (2) binned length data Since the length data is from a random sample, it can be used to generate length frequency histograms. The raw data for lengths is binned by 0.5 mm length increments, from 9.5 to 58.5 mm, and saved as EV***T**.LFHIST. The number of individuals in each length bin is the number with total lengths in the range of the bin id plus .49 mm, i.e., individuals measuring from 32.50 to 32.99 mm are in bin 32.50. (1) 2-M tows were done at stations (n=120) (a) along transect lines at 20 km intervals, with the transect lines 100 km apart, 000.* through 900.*, (b) at selected stations on transect lines between these cardinal lines, 450.*, 350.*, 250.*, 150.* and (c) at selected stations inside Biscoe Islands and up through the Grandidier Channel. (2) length measurements and red thelycums are recorded only when > 10 individual E. superba are in the catch. If multiple tows are done at the same station, replicate length frequencies are not necessarily done if the catch looks about the same size (n=2 with no length frequency for a 2M tow because the grid location was a repeat). ***.raw and ***.LFHIST files are available for 59 grid locations, 57 from 2M tows, 2 from 1M tows where there were not enough krill from the 2M catch, but krill were definitely found at the station. (1) trawl specifications: the 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: *a 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 *the 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. (3) treatment of catch: The goal is (a) to characterize the total catch, i.e., numbers and volumes of each type of organism, and (b) 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 *the contents of the tub are sorted on board for macrozooplankton and micronekton, and samples measured, preserved and frozen as detailed in the following sections. *TRAWL CATCH LOG 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 All krill are removed to a separate bucket/tub, either with a coarse mesh scoop or tweezers depending whether or not a growth experiment will be started. From the total catch of krill, the following samples are taken and data recorded: - krill TL/MF, with volume, of 100 random individuals (sample preserved in 10% formalin) - if a growth experiment is to be conducted, 100 individuals are selected randomly and put in a separate bucket and placed in the aquarium room - individual or groups of krill identified, measured and frozen for chemical composition and condition factor; vial numbers and numbers of animals in vials recorded - obtain the volume of krill that are not preserved, frozen or used in experiments measured - total volume and numbers of krill calculated (b) FISH All fish larvae are removed and immediately preserved in 95-100% ethanol in 20 ml scintillation or 7 ml glass vials. The larvae are counted and identified asap. All adult fish are removed and frozen in ziplock bags labeled inside and outside in -70 freezer. Pleuragramma antarcticum adults are frozen individually, after being measured for total and standard length and weighed on a spring scale. (c) SALPS The total volume of all salps is measured with a graduated cylinder. Several individuals from each size category are preserved with the sample to verify species identification. (d) rare species are separated, idenitifed and counted for the entire sample: 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 (f) the volume of the remaining common organisms is measured in a graduated cylinder , and all individuals from a subsample of that volume identified and counted; these species are usually Thysanoessa, Limacina, Themisto gauchichaudii, E. frigida or a combination of several of the above. (g) all rare organisms, type specimens of salps, and either the subsample of common organisms or the entire sample are preserved together in 10% formalin (2) KRILL TL/MF (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. MF refers to the red thelycum on the female and indicates the females that have entered the reproductive cycle. A random sample of 100 individuals is measured/observed. The volume of these 100 individuals is measured with a graduated cyclinder. If the 100 animals are of one size class, just these 100 krill are preserved for later analysis of physiological maturity stage. If the 100 animals are of two or more size classes, then an additional random sample of about 100 individuals (volume measured) is preserved along with the 100 measured individuals. The total volume preserved is recorded. Tows are done at standard stations along the cardinale 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 2-M trawl collections is to verify the alternate scatterers for the acoustics. Targeted tows are set for the depth of the acoustic trace. 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. The information on the trawl record and trawl catch log for each event is summarized in two files: trawl_rec and trawl_catch. Detailed data on E. superba is found in two files for each event, ***.raw and ***.LFHIST. At two stations (EV354T86 and EV404T103) there were not enough krill in the 2M Metro net catch for a length frequency, but there were in in the 1M. In the first line of the ***.raw and ***.LFHIST files for these two stations is (1M) to indicate the origin of the catch. For all other stations the TL/MF data are for krill from the 2M Metro net catch. zooplankton community composition, length frequency, wet weight of euphausia superba, physiological maturity stage ascii, comma separated variable The first line is the number of columns a # sign, and identifying information for the event, each following line identifies each variable with units. Raw data follows. /home/data3/data/jan94/trwl2m/krill_lfhist/***.LFHIST /krill_raw/***.raw /trawl_rec File names for each tow are identified with the event and tow number, then the data type: i.e. EV***T**.raw and EV***T**.LFHIST. There are 59 for mar93. Robin M. Ross, Langdon B. Quetin none Robin M. Ross, Langdon B. Quetin Robin M. Ross, Tim Newberger, H. Coe, T. Coe, D. Post, G. Catalano, L. Serold, S. Pryor On board sample analysis by above. Preserved sample analysis back at UCSB by T Shaw, and J Squier. Robin M. Ross, H. Coe, T. Coe, D. Post, G. Catalano, T. Shaw Robin M. Ross, T. Coe Robin M. Ross ***.raw and ***.LFHIST files for Phase I and Phase III: 13 Nov 1994 ***.raw and ***.LFHIST files for Phase II: 16 Nov 1994 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. Plots of length-frequency distributions are inspected for outliers, and unpredicted size animals in certain locations. Original records are checked to verify these outliers. Spread sheets for each tow are laid out to automatically calculate the split factor due to subsamples both pre-preservation and during sample analysis after preservation. Calculations are set up to arrive at the same number in two separate routes to check that all factors have been incorporated.

Datafile Form V1.2 for describing a data file.