Weight and len h data of zooplankton in the Weddell in austral sprin

Transcription

1 Weight and len h data of zooplankton in the Weddell in austral sprin Elke Mizdalski Ber. Poiarforsch. 55 (1988) ISSN

2

3 Contents Page... Introduction Methode... Results... Coelenterata... Gastropoda... Polychaeta... Ostracoda... Copepoda... Euphausiacea... Decapoda... Amphipoda... Chaetognatha... Tunicata... Pisces... Tables References Annex (Station List)... 69

4

5 ntroduction Very little is known about the composition and biornass of zooplankton in the Antarctic pack-ice Zone in winter. During the third leg of the Winter Weddell Sea Project (WWSP '86) with RV "Polarstern", frorn 28 September to 14 December 1986, zooplankton samples were taken for biornass studies. The following data lists and diagrarns show wet, dry and of organic matter (ash-free dry ) of zooplankton organisms of various taxa and size classes at different stations. Further quantitative investigations of the total zooplankton biornass in the Weddell Sea during late winter will make use of these data in addition to the catch data and the number of individuals in each taxa. The srnallest organism that was sorted out, rneasured 0.25 rnm, the largest 160 mrn. For detailed inforrnation about cruise track, station lists and gear See Annex and Schnack-Schiel (1 987). Methods Most of the zooplankton organisms were taken frorn Bongo net hauls (rnesh size 300 prn). A Nansen net (rnesh size 100 prn) was used for copepods and larvae smaller than about 1 mrn, and adult euphausiids and other large specimens were obtained frorn a RMT (Rectangular Midwater Trawl) and a Krill net. The locations of the stations are shown in Figures 1-5. The fresh samples were kept cool in ice boxes and sorted fresh as far as possible according to species, developrnental Stage and Sex. Siphonophores, gastropods, polychaets, ostracods, euphausiids (furciliae - adult), decapods, amphipods, chaetognaths, salps and fish larvae were caught by forceps and measured (total length; fish larvae: standard length) on board. Then 1-60 similar specirnens were placed in a glass via1 and frozen at -80Â C Fresh copepods frorn the Bongo hauls were identified and sorted according to stages and Sex. Here up to 200 specimens were used for one sam-

6 Fig.l. Cruise track of RV "Polarstern" during ANT V13 with stations outside the main investigation areas.

7 Fig.2. Station map of investigation area I (October 1986) Fig.3. Station map of investigation area l (November 1986)

8 Fig.4. Station rnap of investigation area 11 Fig.5. Station map of investigation area 111

9 ple. Formalin-preserved copepods of sorne representative stations were rneasured in the laboratory for total length. While rnost of the stages showed little size variation Calanus propinquus copepodite stage V (CV) and fernales of Calanoides acutus showed a broad range of lengths. These stages were therefore subdivided into two size categories, sorted and rneasured separately once a sufficient nurnber of individuals had been found. The small cyclopoid copepods, copepod nauplii and the euphausiid brood were sorted with a pipette and washed onto pre-cornbusted and pre-weighed GFIC-filters (also up to 200 specirnens per filter). To correct the weighing results, filters with seawater only were frozen and dealt with in the sarne manner. Altogether 1192 sarnples were taken of 54 taxa (Table 1). Table 1. List of analyzed taxa. Coelenterata: Calycopsis borchgrevinki (BROWNE, ) Diphyes antarctica MOSER, Diphyes sp. Pyrostephos vanhoeffeni MOSER, Gastropoda: Clione limacina (PHIPPS, 1774) Clio pyramidata LINNAEUS, 1767 Limacina heticina (PHI PPS, 1774) "Echinospira"-larvae Polychaeta: Pelagobia longicirrata GREEF, Tomopteris sp. Vanadis antarctica McINTOSH, 1885 Ostracoda: Conchoecia sp. Copepda: Calanus propinquus BRADY, 1883: Calanoides acutus (GIESBRECHT, 1902): ßhincalanu gigas BRADY, 1 883: Metridia gerlachei GIESBRECHT, 1 902: Metridia curticauda GIESBRECHT, 1889: Heterorhabdus austrinus GIESBRECHT, 1902: Heterorhabdus farrani BRADY, : Euchaeta antarctica GIESBRECHT, 1902: Gaidius tenuispinus (G.O. SARS, 1 900): Etideopsis minor (WOLFENDEN, 191 1): Euchirella rosfromagna WOLFENDEN, : Haloptilus ocellatus WOLFEN DEN, 1 905: Haloptilus oxycephalus (GIESBRECHT, 1888): F, M, C V F, M, C V F, M, C II - V F, M, C V F, M, C V F, M, C V F, M, C IV - V F,Cl-V F, M, C V F F F,CV F,CV

10 Copepda cont. Euphausiacea: Decapoda: Amphipoda: Racovitzanus antarctica GIESBRECHT, 1902 Scolecifhricella minor (BRADY, 1 883) Scaphocalanus sp. Spinocalanus sp. Ctenocalanus sp. Microcalanus pygmaeus (G.O. SARS, 1900) Sfephus longipes GIESBRECHT, 1902 Oncaea spp. Oithona spp. Copepod nauplii Euphausia superba DANA, 1850: F, M, juv., furc. Euphausia crystallorophias HOLT & TATTERSALL, 1906: F, M, juv., MN, N, eggs Euphausia frigida HANSEN, 1911 : calypt Thysanoessa macrura G.O. SARS, 1883: F, M, juv., furc., calypt. I Acantephyra pelagica (RISSO, 181 6) a) Hyperiidea: Cyllopus lucasii BATE, 1862 Hyperiella dilatata STEBBING, 1888 Hyperiella macronyx (WALKER, 1 906) Hyperoche sp. Prirnno macropa GUERIN-MENEVILLE, 1836 Scina sp. b) Gammaridea: Cyphocaris sp. Eusirus sp. Orchomene plebs (H U RLEY, 1 965) Orchomene sp. Chaetognatha: Tunicata: Pisces: Eukrohnia hamata (MÃ BIUS 1875) Sagitta gazellae VON RITTER-ZAHONY, 1909 Sagitta marri DAVI D, 1956 Salpa sp. Pleuragramma antarcticurn BOULENGER, 1902 In the Alfred Wegener Institute the sarnples were stored in a -30Â roorn. For measurements the anirnals were unfrozen and put into pre-combusted and pre-weighed alurninium vials. Wet was rneasured using a Sartorius 1712MP8 balance. Dry s and ash-free dry s were deterrnined as in Bilrnstedt (1974). The sarnples were dried in an oven at 60Â for 24 hours (adult and juvenile Euphausia spp. for 48 hours). Following rneasurernent of the dry the sarnples were incinerated in a muffle furnace at 5OO0C for 12 hours (adult and juvenile Euphausia spp. for

11 24 hours) and ash was substracted frorn dry to calculate ash-free dry. Both dry and ash were rneasured on Sartorius superrnicro 4504MP8 after cooling the samples in a desiccator. For the species on filters only dry and ash-free dry was deterrnined. All results are presented in tables. The lengthldry, lengthlorganic matter and dry lorganic matter relationships for Euphausia superba, Euphausia crystallorophias, Thysanoessa macrura, Calanus propinquus, Calanoides acutus, ßhincalanu gigas, Metridia gerlachei and Euchaeta antarctica are shown in Figures 6-29.

12 Results Tab. 2 : Calycopsis borchgrevinki Station Length Wet Dry Ash-free dry (mm) Tab. 3: Diphyes antarctica Station Length Wet Dry Ash-free dry

13 Tab. 4 : ~iphonophora indet. Station Lenqth Wet Dry Ash-free dry (m) Tab. 5 : Pyrostephos vanhoeffeni Station Length Wet Dry Ash-free dry

14 Tab. 6: Clione limacina Station Length Wet Dry Ash-free dry (nun) Tab. 7: Clio pyramidata Station Length Wet Dry Ash-free dry

15 Station Length Wet Dry Ash-free dry (mm) Tab. 8: Limacina helicina Station Length Wet Dry Ash-free dry Tab. 9 : "Echinospiral'-larvae Station Length Wet Dry Ash-free dry

16 Station Length Wet Dry Ash-free dry (mm) img) img) Tab. 10: Pelagobia lonqicirrata Station Length Wet Dry Ash-free dry (m) img) Tab. 11: Tomopteris sp. Station Length Wet Dry Ash-free dry (nun) imq) Tab. 12: Vanadis antarctica Station Length Wet Dry Ash-free dry img) img)

17 Station Wet Dry Ash-free dry Tab. 13: Conchoecia sp. Station Length Wet Dry Ash-free dry (m)

18 Tab. 14 : Calanus propinquus, female Station Lenqth Wet Dry Ash-free dry (mm) img) Tab. 15 : Calanus propinquus, male Station Lenyth Wet Dry Ash-free dry img)

19 Tab. 16: Calanus propinquus, C V Station Lenqth Wet weiqht Dry Ash-free dry (mm) Tab. 17: Calanus propinquus, C IV Station Lenqth Wet Dry Ash-free dry

20 Station Lenqth Wet Dry Ash-free dry (mm) Tab. 18 : Calanus propinquus, C I11 Station Length Wet Dry Ash-free dry Tab. 19 : Calanoides acutus, f emale Station Length Wet Dry Ash-free dry

21 Tab. 20: Calanoides acutus, male Station Length Wet Dry Ash-free dry (nun) img ) Tab. 21: Calanoides acutus, C V Station Length Wet Dry Ash-free dry Tab. 22: Calanoides acutus, C IV Station Length Wet Dry Ash-free dry

22 Station Length Wet Dry Ash-free dry (mm) Tab. 23: Calanoides acutus, C I11 Station Length Wet Dry Ash-free dry (m) img) Tab. 24: Rhincalanus gigas, female Station Length Wet Dry Ash-free dry

23 Tab. 25: Rhincalanus gigas, male Station Length Met Dry Ash-free dry (mm) (mg img) Tab. 26: Rhincalanus gigas, C V Station Length Wet Dry Ash-free dry Tab. 27: Rhincalanus qiqas, C IV Station Length Wet Dry Ash-free dry

24 Station Length Wet Dry Ash-free dry (m) img ) img) Tab. 28: Rhincalanus qiqas, C I11 Station Length Wet Dry Ash-free dry (nun) img) Tab. 29: Rhincalanus gigas, C I1 Station Lenqth Wet Dry Ash-free dry (mm) Tab. 30: Metridia gerlachei, female Station Length Wet weiqht Dry Ash-free dry imm) img) img)

25 Station Length Wet Dry Ash-free dry (mm) Tab. 31: ~etridia gerlachei, male Station Length Wet Dry Ash-free dry (mg ) Tab. 32: Metridia gerlachei, C V Station Length Wet Dry Ash-free dry (mm)

26 Station Length Wet Dry Ash-free dry (mm) Tab. 33: Metridia gerlachei, C IV Station Length Wet Dry imgl Ash-free dry Tab. 34: Metridia gerlachei, C I11 Station Length Wet Dry Ash-free dry img)

27 Tab. 35: Metridia curticauda, female Station Length Wet Dry Ash-free dry (mm) Tab. 36: Metridia curticauda, male Station Length Wet Dry Ash-free dry (mm) img) Tab. 37: Metridia curticauda, CV Station Length Wet Dry Ash-f ree dry (mm) Tab. 38 : Heterorhabdus austrinus, female Station Length Wet weiqht Dry Ash-free dry (mm) img) img)

28 Tab. 39 : Heterorhabdus austrinus, male Station Length Wet Dry Ash-free dry (mm) (rng ) Tab. 40: Heterorhabdus austrinus, C V Station Length Wet Dry Ash-free dry Tab. 41 : Heterorhabdus farrani, fernale Station Length Wet Dry Ash-free dry (mm) Tab. 42: Heterorhabdus farrani, male Station Length Wet Dry Ash-free dry

29 Tab. 43: Heterorhabdus farrani, C V Station Length Wet Dry Ash-free dry imm) img) img) img) Tab. 44 : Heterorhabdus farrani, C IV Station Lenqth Wet Dry Ash-free dry img) Tab. 45 : Euchaeta antarctica, f emale Station Length Wet Dry Ash-free dry Tab. 46: Euchaeta antarctica, C V Station Length Wet Dry Ash-free dry (mm) tmg) img)

30 Station Length Wet Dry Ash-free dry img) Tab. 47: Euchaeta antarctica, C IV Station Lenqth Wet Dry Ash-free dry (mg ) Tab. 48: Euchaeta antarctica, C I11 Station Length Wet Dry Ash-free dry img)

31 Tab. 49: Euchaeta antarctica, C I1 Station Lenqth Wet Dry Ash-free dry (mm) Tab. 50: Euchaeta antarctica, C I Station Length Wet Dry Ash-free dry (mg ) Tab. 51 : Gaidius tenuispinus, f emale Station Lenqth Wet weiqht Dry weiqht Ash-free dry

32 Tab. 52: Gaidius tenuispinus, male Station Lenqth Wet Dry Ash-free dry (mm) Tab. 53: Gaidius tenuispinus, C V Station Lenqth Wet Dry Ash-free dry (mm) Tab. 54: Gaidius tenuispinus, C IV Station Lenqth Wet Dry Ash-free dry Tab. 55: Gaidius tenuispinus, C I11 Station Length Wet Dry Ash-free dry (mm)

33 Tab. 56: Aetideopsis rninor, female Station Length Wet Dry Ash-free dry (mm) Tab. 57 : Euchirella rostromaqna, f emale Station Length Wet Dry Ash-free dry (mm) Tab. 58 : Haloptilus ocellatus, female Station Lenqth Wet Dry Ash-free dry (mm) Tab. 59: Haloptilus ocellatus, C V Station Length Wet Dry Ash-free dry (mm)

34 Tab. 60 : Haloptilus oxycephalus, female Station Lenqth Wet Dry Ash-free dry (mm) img) Tab. 61: Haloptilus oxycephalus, C V Station Length Wet Dry Ash-free dry Tab. 62: Racovitzanus antarcticus, female + C V Station Length Wet Dry Ash-free dry (nun)

35 Tab. 63: Scolecithricella minor, adult + C V Station Length Wet Dry Ash-free dry (mm) Tab. 64: Scaphocalanus sp., female + C V Station Lenqth Wet Dry Ash-free dry (mm) Tab. 65: Spinocalanus sp., female + C V Station Length Wet Dry Ash-free dry (mm)

36 Tab. 66: Total length, dry and ash-free dry (median values) of the copepods weighed On filters. Length Dry Ash-free No. of dry samples (mm) Ctenocalanus sp., ad.+ CV Microcalanus pygmaeus, ad. ', cv Stephus lonqipes, ad.+ CV Oncaea spp., ad. + copepodites 02 thona spp., ad. + copepodites Copepod nauplii

37 Tab. 67: Euphausia superba, female Station Length Wet Dry Ash-free dry (m) img ) Tab. 68 : Euphausia superba, male Station Lenqth Wet Dry Ash-free dry (mg )

38 Station Length Wet Dry Ash-free dry (mm) Tab. 69: Euphausia superba, juv. Station Length Wet Dry Ash-free dry (mm) Tab. 70 : Euphausia crystallorophias, female Station Length (m) Wet Dry Ash-free dry

39 Station Lenqth Wet Dry Ash-free dry (mm) img) Tab. 71: Euphausia crystallorophias, male Station Lenqth Wet Dry Ash-free dry

40 Station Length Wet Dry Ash-free dry (mm) Tab. 72 : Euphausia crystallorophias, juv. Station Lenqth Wet weiqht Dry Ash-free dry (mm)

41 Station Lenqth Wet Dry Ash-free dry (m) (mq) img) Tab. 73: Thysanoessa macrura, female Station Lenqth Wet Dry Ash-free dry

42 Tab. 74: Thysanoessa macrura, male Station Lenqth Wet Dry Ash-free dry Tab. 75: Thysanoessa macrura, juv. Station Lenqth Wet Dry mg) Ash-free dry img)

43 Station Length Wet Dry Ash-free dry (m) img) Tab. 76: Total length, dry and ash-free dry (median values) of the euphausiid brood. Species/staqe Length Wet Dry Ash-free No. of dry samples (m) E. crystall orophias M eggs 0.60 nauplii metanauplii 0.70 M E. friqida calyptopes I calyptopes I T. macrura calyptopes I Tab. 77 : Acantephyra pelagica Station Length Wet Dry Ash-free dry img )

44 Tab. 78 : Cyllopus lucasii Station Lenqth Wet Dry Ash-free dry (mm) Tab. 79: Hyperiella dilatata Station Lenqth Wet Dry Ash-free dry (mm)

45 Tab. 80: Hyperiella spp. Station Length Wet Dry Ash-free dry imm) Tab. 81: Hyperiella macronyx Station Lenqth Wet weignt Dry Ash-free dry.* Tab. 82 : Hyperoche sp. Station Length Wet Dry Ash-free dry img) img)

46 Tab. 83: Primno macropa Station Length Wet Dry Ash-free dry (mm)

47 Tab. 84: Sdna sp. Station Length Wet Dry Ash-free dry (mm) Tab 85 : Cyphocaris sp. Station Length Wet Dry Ash-free dry Tab. 86: Eusirus sp. Station Length Wet Dry Ash-free dry (mm) Tab. 87 : Orchomene plebs Station Lenqth Wet Dry weiqht Ash-free dry (mm)

48 Tab. 8 8 : Orchomene sp. Station Length Wet Dry Ash-free dry (mm) Tab. 89: Eukrohnia hamata Station Length Wet Dry Ash-free dry (mm)

49 Tab. 90: Sagitta gazellae Station Length Wet Dry weiqht Ash-free dry (mm) Tab. 91 : Sagitta marri Station Lenqth Wet Dry Ash-free dry (mm)

50 Tab. 92: Salpa sp. Station Length Wet Dry Ash-free dry Tab. 93: Pleuraqrama antarcticum Station Length Wet Dry Ash-free dry

51 Station Length Wet Dry Ash-free dry imm) img)

52 H Females + Males # Juveniles Fig.S. Relationship between total length!tl) and dry (TG) in Euphausia superba showing the curve with the best fit (y=-0,4982+0,1981x-o,02295x2+o,001712x3) >i Females + Males * Juveniles ++.A Fig.7. Relationship between total length (TL) and organic matter (OS) in Euphausia superba showing the curve with the best fit (y=1,258-0,1384~-0,006317x2+0,001283x3)

53 X Females + Males Juveniles Fig.8. Relationship between dry (TG) and organic matter (OS) in Euphausia superba (y =-O,O4277+0,8409x) showing the curve with the best fit

54 120 TG Ã Females + Males 100 # Juveniles TL imml Fig.9. Relationship between total length (TL) and dry!tg) in Euphausia crystallorophias showing the curve with the best fit (y=-24,73+4,653~-0,2680~~+0,005922x~) Ã Females + Males f Juveniles Fig.lO. Relationship between total length (TL) and organic matter (OS) in Euphausia crystallorophias showing the curve with the best fit (Y=-25,25+4,696x-0,2663x x3)

55 M Females i Males # Juveniles Fig.ll. Relationship between dry (TG) and organic matter (OS) in Euphausia crystallorophias showing the curve with the best fit (Y=-O,3028+0,8765x)

56 H Females M i Males 1 Fig.12. Relationship between total length (TL) and dry (TG) in Thysanoessa macrura showing the curve with the best fit (Y=-4,017+1,191x-0,1087~+0,004068x3) M Females + Males # Juveniles Fig.13. Relationship between total length (TL) and organic matter (OS) in Thysanoessa macrura showing the curve with the best fit (Y=-3,116+0,9260~-0,008507x2+0,003262x3)

57 12 OS * Females 10 + Males # Juveniles a Fig.14. Relationship between dry (TG) and organic matter (OS) in Thysanoessa macrura showing the curve with the best fit (Y=-O,O1039+0,8471x)

58 1.5 1 TG C I11 X C IV X 0 C V M Females a + Males X! i ' 5 6 Fig.15. Relationship between total length (TL) and dry (TG) in Calanus propinquus showing the curve with the best fit (y=0,04627-~,1432x+0,06677~) OS (mgl X C IV 0 C V X Females + Males O! X X X i Fig.16. Relationship between total length (TL) and organic matter (OS) in Calanus propinquus showing the curve with the best fit (Y=-0, ,09172~+0,05254~)

59 C I11 C IV C V Females Males Fig.17. Relationship between dry (TG) and organic matter (OS) in Calanus propinquus showing the curve with the best fit (Y=-O,O1831+0,8695x)

60 Fig.18. Relationship between total length (TL) arid dry (TG) in Calanoides acutus showing the curve with the best fit (y=0,1608-0,1670x+0,04891x2) 0 C V * Fernales + Males Fig.19. Relationship between total length (TL) and organic matter (OS) in Calanoides acutus showing the curve with the best fit (y=0,1750-0,1698.x+0,04492x2)

61 z C 111 X C IV 0 C V X Females + Males Fig.20..Relationship between dry (TG) and organic matter (OS) in Calanoides acutus showing the curve with the best fit (Y=-0, ,8550~1

62 C I1 C 111 C IV C V Females Males Fig.21. Relationship between total length (TL) and dry (TG> in Rhincaianus gigas showing the curve with the best fit (y=0,2341-0,1939x+0,04244x2) C I1 C I11 C IV C V Females Males Fig.22. Relationship between total length (TL) and organic matter (OS) in Rhincalanus gigas showing the curve with the best fit (y=0,2701-0,1981x+0,03816x2)

63 Fig.23. Relationship between dry (TG) and organic matter (OS) in Rhincalanus gigas showing the curve with the best fit (Y=-O,O3491+0,8331x)

64 TG (mal z C 111 X C IV 0 C V X Females B i Males M ^ * z +- 0 l Fig.24. Relationship between total length (TL) and dry (TG) in Metridia gerlachei showing the curve with the best fit (Y=-0, ,1464x-0,08054$+0,01737x3) z C I11 X C IV 0 C V X Females i Males Fig.25. Relationship between total length (TL) and organic matter (OS) ini Metridia gerlachei showing the curve with the best fit (Y=-0, ,1119~-0,06264~+0,01345x3>

65 0.2 * Females + Males Fig.26. Relationship between dry (TG) and organic matter (OS) in Metridia gerlachei showing the curve with the best fit (Y=-0, ,7532~)

66 C IV C V Females Fig.27. Relationship between total length (TL) and dry (TG) in Euchaeta antarctica showing the curve with the best fit (y=0,2826-0,3072x+0,08434x2) C I C I1 C I11 C IV C V Females Fig.28. Relationship between total length (TL) and organic matter (OS) in Euchaeta antarctica showing the curve with the best fit (Y-0,2776-0,2960~ x~)

67 C I11 C IV C V Females Fig.29. Relationship between dry (TG) and organic matter (OS) in Euchaeta antarctica showing the curve with the best fit ( Y=-O,O2263+0,8811x)

68 Acknowledgements First of all l would like to thank Dr. S. Schiel for continuous advise during the work at sea and in the laboratory. Dr. G. Hubold and Dr. E. Boysen-Ennen contributed largely to the concept of the project. I owe a special thank to Dr. W. Hagen, who shared his plankton hauls with me and helped rne sort the samples. Dr. M. Reinke made me acquainted with the PC and aided in the tables, W. Wür wro~e the graphic program, S. Hain let me work on his private PC and S. Marschall typed the text. Thanks also to Dr. R. Bohrer for linguistic improvements. References BAmstedt, U. (1974): Biochemical studies On the deep-water pelagic community of Korsfjorden, Western Norway. SARSIA 56, Schnack-Schiel, S. (1 987): Die Winter-Expedition mit FS "Polarstern" in die Antarktis (ANT V11-3). Ber. Polarforsch. 39, 259 pp.

69 Annex Station List (after Schnack-Schiel 1987)

70 Stat. NO. Date Position Echo Gear Hau1 Day Start Hau1 Depth depth No. time dur. (m) (GMT) (min) (m) FD Be B0 B0 FD B0 I30 B0 B0 B0 FD B0 B0 B0 B0 RMT RMT B0 B0 RMT FD B0 B0 KN FD B0 NSN NSN B0 B0 FNT RMT RMT B0 NSN

71 Stat. No. Date Position Echo Gear Hau1 Day Start Hau1 Depth depth No. time dur. (m) (GMT) (min) (m) EQ NSN m m m m m m EQ RMT KM B0 KM m EQ RMT B0 EQ B0 E0 B0 m RMT RMT EQ m B0 E0 B0 NSN m NSN

72 Stat. NO. Date Position Echo Gear Hau1 Day Start Hau1 Depth depth No. time dur. (m (GMT) (min) (m) 015O44,4 'W 012Â 30 3 'W 01Z023,7 'W 011Â 33, 'W 008Â 16 O'W 008Â 33 2 'W 003O56,l 'W 000Â 22 8 '0 000Â 22 0 '0 000Â 23, '0 Abbreviations EQ KN NSN BMT T M N A Bongo net Krill net Nansen closing net Rectangular Midwater Trawl DaY Dawn Niqht Dusk