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Bester, Marthán Nieuwoudt; Odendaal, Paul N (2015): Seal census raw data during POLARSTERN expedition ANT-XV/3 (PS48) [dataset]. University of Pretoria, Department of Zoology & Entomology, PANGAEA, https://doi.org/10.1594/PANGAEA.854467, In supplement to: Gurarie, Eliezer; Bengtson, John L; Bester, Marthán Nieuwoudt; Blix, Arnoldus Schytte; Cameron, Michael; Bornemann, Horst; Nordøy, Erling Sverre; Plötz, Joachim; Steinhage, Daniel; Boveng, Peter (2016): Distribution, density and abundance of Antarctic ice seals off Queen Maud Land and the eastern Weddell Sea. Polar Biology, 40(5), 1149-1165, https://doi.org/10.1007/s00300-016-2029-4

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Abstract:
The density, species composition, and possible change in the status of pack ice seals within the Weddell Sea were investigated during the 1997/1998 summer cruise of the RV „Polarstern“ (ANT-XV/3, PS48). Comparisons were made with previous surveys in the Weddell Sea where it was assumed that all seals were counted in a narrow strip on either side oft he ship or aircraft. A total of 15 aerial censuses were flown during the period 23 January – 7 March 1998 in the area bounded by 07°08' and 45°33' West longitude. The censused area in the eastern Weddell Sea was largely devoid of pack ice while a well circumscribed pack ice field remained in the western Weddell Sea. A total of 3,636 (95.4 %) crabeater seals, 21 (0.5 %) Ross seals, 45 (1.2 %) leopard seals and 111 (2.9 %) Weddell seals were observed on the pack ice during a total of 1,356.57 linear nautical miles (244.2 nm) of transect line censused. At a mean density of 21.16 1/nm**2 over an area of 244.2 nm, it is the highest densities on record for crabeater seals, density of up to 411.7 1/nm**2 being found in small areas. The overall high densities of seals (30.18 1/nm**2) recorded for the eastern Weddell Sea (27.46 1/nm**2, 0.27 1/nm**2, and 0.66 1/nm**2 for crabeater, leopard and Weddell seals respectively) is a consequence of the drastically reduced ice cover and the inverse relationship that exists between cover and seal densities. Ross seal densities (0.08 1/nm**2) were the lowest on record fort the area. It is suggested that seals largely remain within the confines of the pack ice despite seasonal and annual changes in its distribution. Indications are that in 1998 the El Niño has manifested itself in the Weddell Sea, markedly influencing the density and distribution of pack ice seals.
Related to:
Ackley, Stephen F; Bengtson, John L; Bester, Marthán Nieuwoudt; Blix, Arnoldus Schytte; Bornemann, Horst; Boveng, Peter; Boyd, I; Cameron, Michael; Nordøy, Erling Sverre; Plötz, Joachim; Siniff, D; Southwell, C; Steinhage, Daniel; Stewart, Brent S; Stirling, J; Torres, J; Yochem, P K (2006): The International Antarctic Pack Ice Seals (APIS) Program. Multi-disciplinary Research into the Ecology and Behavior of Antarctic Pack Ice Seals. Summary Update. The Expert Group on Seals (EGS); Scientific Committee on Antarctic Research (SCAR). Marthan N. Bester, D.Sc., Chief Officer, Brent S. Stewart, Ph.D., J.D., Secretary (eds.)., 25 pp, hdl:10013/epic.37461.d001
Bester, Marthán Nieuwoudt; Odendaal, Paul N (1999): Abundance and distribution of Antarctic pack ice seals in the Weddell Sea. In: Antarctic Ecosystems: Models for Wider Ecological Understanding. W. Davison, C. Howard-Williams & P. Broady (eds), Caxton Press, Christchurch, New Zealand, 51-55
Bester, Marthán Nieuwoudt; Odendaal, Paul N (1999): Abundance and distribution of Antarctic pack ice seals in the Weddell Sea. In: W.E. Arntz & J. Gutt (eds) The Expedition ANTARKTIS XV/3 (EASIZ II) of "Polarstern" in 1998, Berichte zur Polarforschung = Reports on Polar Research, 301, 102-107, https://doi.org/10.2312/BzP_0301_1999
Southwell, C; Bengtson, John L; Bester, Marthán Nieuwoudt; Blix, Arnoldus Schytte; Bornemann, Horst; Boveng, Peter; Cameron, Michael; Forcada, J; Laake, J; Nordøy, Erling Sverre; Plötz, Joachim; Rogers, Tracey; Southwell, D; Steinhage, Daniel; Stewart, Brent S; Trathan, P (2012): A review of data on abundance, trends in abundance, habitat use and diet of ice-breeding seals in the Southern Ocean. CCAMLR Science, 19(49), hdl:10013/epic.40419.d001
Further details:
Documentation of the South African Antarctic Pack Ice Seals Census (APIS) Programme 1998 during POLARSTERN expedition ANT-XV/3 (PS48). hdl:10013/epic.46171.d001
Project(s):
Coverage:
Median Latitude: -70.169806 * Median Longitude: -19.855989 * South-bound Latitude: -73.899833 * West-bound Longitude: -45.550500 * North-bound Latitude: -62.062833 * East-bound Longitude: -8.149333
Date/Time Start: 1970-01-01T00:00:00 * Date/Time End: 1998-03-07T14:06:00
Minimum ALTITUDE: 60.96 m * Maximum ALTITUDE: 91.44 m
Event(s):
SA_APIS_Census (South African Antarctic Pack Ice Seals Census) * Latitude Start: -70.576000 * Longitude Start: -8.149330 * Latitude End: -62.672000 * Longitude End: -44.978800 * Date/Time Start: 1998-01-23T15:00:00 * Date/Time End: 1998-03-07T14:10:00 * Method/Device: Aircraft (AC)
Comment:
Densities were calculated by dividing (1) the area surveyed during each census = width of trip delineated by sighting bars (1-5 on both sides combined = 1023 ft or 0.1682 nm) multiplied by the toral length of census line for each census, by (2) numbers of each species encountered in during each census. Furthermore, at some points densities for individual frames were calculated to illustrate some points, but not for overall densities per census (i.e. Bester and Odendaal did not calculate densities for each frame, but the then the mean +- SD (SE for all the frames of a single species).
Parameter(s):
#NameShort NameUnitPrincipal InvestigatorMethod/DeviceComment
1IdentificationIDBester, Marthán NieuwoudtCensus_Leg_Frame; Each day is considered a new census; Within each census legs denote start and end of the strip installation; Within each leg species specific counts are accumulated within frames of three-minutes (denoted as blocks in Gurarie et al.)
2LATITUDELatitudeBester, Marthán NieuwoudtGeocode – Leg start
3LONGITUDELongitudeBester, Marthán NieuwoudtGeocode – Leg start
4Latitude 2Latitude 2Bester, Marthán NieuwoudtLeg end
5Longitude 2Longitude 2Bester, Marthán NieuwoudtLeg end
6DATE/TIMEDate/TimeBester, Marthán NieuwoudtGeocode – UTC Interpolation equidistantly between 2:30 and 4:30 min
7Date/time endDate/time endBester, Marthán NieuwoudtGeocode - UTC Interpolation equidistantly between 2:30 and 4:30 min
8Time of dayTime of dayBester, Marthán NieuwoudtUTC
9Time of dayTime of dayBester, Marthán NieuwoudtUTC
10DistanceDistancekmBester, Marthán NieuwoudtEstimated first by dividing the straight line distance traveled in a Leg by the corresponding number of Frames, then calculated along the given latitude/longitude geocodes of that cell according to ARCCOS(SIN(H2*PI()/180)*SIN(J2*PI()/180)+COS(H2*PI()/180)*COS(J2*PI()/180)*COS(I2*PI()/180-K2*PI()/180))*6366.707
11ALTITUDEAltitudemBester, Marthán NieuwoudtGeocode – Flight altitude of helicopter. The bin angles were constant (every 10 degrees from 30 to horizon) but width depended upon altitude
12Speedvkm/hBester, Marthán Nieuwoudtof helicopter
13Census strip-widthCensus strip-widthmBester, Marthán NieuwoudtCumulative width of bins 1-5
14LengthlkmBester, Marthán NieuwoudtCumulative lenght of bins 1-5 along the strip
15SideSideBester, Marthán NieuwoudtObservation from left or right seat resp. side of the helicopter
16Lobodon carcinophagaL. carcinophaga#Bester, Marthán NieuwoudtCumulative counts of crabeater seals (Lobodon carcinophaga) within bin 1 to 5
17Ommatophoca rossiiO. rossii#Bester, Marthán NieuwoudtCumulative counts of Ross seals (Ommatophoca rossii) within bin 1 to 5
18Leptonychotes weddelliiL. weddellii#Bester, Marthán NieuwoudtCumulative counts of Weddell seals (Leptonychotes weddellii) within bin 1 to 5
19Hydrurga leptonyxH. leptonyx#Bester, Marthán NieuwoudtCumulative counts of leopard seals (Hydrurga leptonyx) within bin 1 to 5
20Seals, unidentifiedSeals unident#Bester, Marthán NieuwoudtCumulative counts of unidentified seal species within bin 1 to 5
21Lobodon carcinophagaL. carcinophaga#Bester, Marthán NieuwoudtNumber of crabeater seals (Lobodon carcinophaga) in bin 1
22Ommatophoca rossiiO. rossii#Bester, Marthán NieuwoudtNumber of Ross seals (Ommatophoca rossii) in bin 1
23Leptonychotes weddelliiL. weddellii#Bester, Marthán NieuwoudtNumber of Weddell seals (Leptonychotes weddellii) in bin 1
24Hydrurga leptonyxH. leptonyx#Bester, Marthán NieuwoudtNumber of leopard seals (Hydrurga leptonyx) in bin 1
25Seals, unidentifiedSeals unident#Bester, Marthán NieuwoudtNumber of unidentified seal species in bin 1
26Lobodon carcinophagaL. carcinophaga#Bester, Marthán NieuwoudtNumber of crabeater seals (Lobodon carcinophaga) in bin 2
27Ommatophoca rossiiO. rossii#Bester, Marthán NieuwoudtNumber of Ross seals (Ommatophoca rossii) in bin 2
28Leptonychotes weddelliiL. weddellii#Bester, Marthán NieuwoudtNumber of Weddell seals (Leptonychotes weddellii) in bin 2
29Hydrurga leptonyxH. leptonyx#Bester, Marthán NieuwoudtNumber of leopard seals (Hydrurga leptonyx) in bin 2
30Seals, unidentifiedSeals unident#Bester, Marthán NieuwoudtNumber of unidentified seal species in bin 2
31Lobodon carcinophagaL. carcinophaga#Bester, Marthán NieuwoudtNumber of crabeater seals (Lobodon carcinophaga) in bin 3
32Ommatophoca rossiiO. rossii#Bester, Marthán NieuwoudtNumber of Ross seals (Ommatophoca rossii) in bin 3
33Leptonychotes weddelliiL. weddellii#Bester, Marthán NieuwoudtNumber of Weddell seals (Leptonychotes weddellii) in bin 3
34Hydrurga leptonyxH. leptonyx#Bester, Marthán NieuwoudtNumber of leopard seals (Hydrurga leptonyx) in bin 3
35Seals, unidentifiedSeals unident#Bester, Marthán NieuwoudtNumber of unidentified seal species in bin 3
36Lobodon carcinophagaL. carcinophaga#Bester, Marthán NieuwoudtNumber of crabeater seals (Lobodon carcinophaga) in bin 4
37Ommatophoca rossiiO. rossii#Bester, Marthán NieuwoudtNumber of Ross seals (Ommatophoca rossii) in bin 4
38Leptonychotes weddelliiL. weddellii#Bester, Marthán NieuwoudtNumber of Weddell seals (Leptonychotes weddellii) in bin 4
39Hydrurga leptonyxH. leptonyx#Bester, Marthán NieuwoudtNumber of leopard seals (Hydrurga leptonyx) in bin 4
40Seals, unidentifiedSeals unident#Bester, Marthán NieuwoudtNumber of unidentified seal species in bin 4
41Lobodon carcinophagaL. carcinophaga#Bester, Marthán NieuwoudtNumber of crabeater seals (Lobodon carcinophaga) in bin 5
42Ommatophoca rossiiO. rossii#Bester, Marthán NieuwoudtNumber of Ross seals (Ommatophoca rossii) in bin 5
43Leptonychotes weddelliiL. weddellii#Bester, Marthán NieuwoudtNumber of Weddell seals (Leptonychotes weddellii) in bin 5
44Hydrurga leptonyxH. leptonyx#Bester, Marthán NieuwoudtNumber of leopard seals (Hydrurga leptonyx) in bin 5
45Seals, unidentifiedSeals unident#Bester, Marthán NieuwoudtNumber of unidentified seal species in bin 5
46Lobodon carcinophagaL. carcinophaga#Bester, Marthán NieuwoudtNumber of crabeater seals (Lobodon carcinophaga) in bin 6 (disregarded in the analysis)
47Ommatophoca rossiiO. rossii#Bester, Marthán NieuwoudtNumber of Ross seals (Ommatophoca rossii) in bin 6 (disregarded in the analysis)
48Leptonychotes weddelliiL. weddellii#Bester, Marthán NieuwoudtNumber of Weddell seals (Leptonychotes weddellii) in bin 6 (disregarded in the analysis)
49Hydrurga leptonyxH. leptonyx#Bester, Marthán NieuwoudtNumber of leopard seals (Hydrurga leptonyx) in bin 6 (disregarded in the analysis)
50Seals, unidentifiedSeals unident#Bester, Marthán NieuwoudtNumber of unidentified seal species in bin 6 (disregarded in the analysis)
51Ice coverageIce cov%Bester, Marthán Nieuwoudt
52Ice floe coverageFloes cov%Bester, Marthán Nieuwoudt
53Brash ice coverageBrash cov%Bester, Marthán Nieuwoudt
54Cake ice coverageCake cov%Bester, Marthán Nieuwoudt
55Ice floe coverageFloes cov%Bester, Marthán Nieuwoudtsmall, ice floes measuring 10-100 m across
56Ice floe coverageFloes cov%Bester, Marthán Nieuwoudtmedium, ice floes measuring 100-500 m across
57Ice floe coverageFloes cov%Bester, Marthán Nieuwoudtlarge, ice floes greater than 500 m across
58Temperature, airTTT°CBester, Marthán Nieuwoudt
59Wind speedffm/sBester, Marthán Nieuwoudt
60VisibilityVisibilityBester, Marthán Nieuwoudt
61GlareGlareBester, Marthán NieuwoudtGlare present (yes) or not (no)
62ContrastContrastBester, Marthán NieuwoudtQuality of contrast vision classified as high, good, or no
63GearGearBester, Marthán NieuwoudtHelikopter type
64CommentCommentBester, Marthán Nieuwoudt
Size:
19100 data points

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