Acoustic instruments
Two SIMRAD scientific echo sounders, EK 400/38 kHz and EK 400/120 kHz were used during the survey for estimation of fish density. The EK 400/38 was coupled to a digital integrator QD as well as to an analog integrator QM. The details of the instrument settings used are as follows:
|
|
EK 400/38 |
EK 400/120 |
|
Range |
0-100 or 0-250 |
0-100 |
|
Transmitter |
High (5000 W Nom) |
High (1250 W Nom) |
|
Bandwidth |
3.3 kHz |
3.3 kHz |
|
Pulselength |
1.0 ms |
1.0 ins |
|
TVG |
20 log R |
20 log R |
|
Attenuator |
20 dB |
0 |
|
Rec. gain |
8 |
5 |
|
transducer |
8 × 8 ceramic |
Ceramic 10cm Æ |
|
|
Split beam (ES) |
|
QM settings: Gain 20 dB × 10. Threshold 7
A calibration experiment using standard copper spheres performed at Las Palmas 27/8/89 gave the following results: 30x30 transducer, SL+VR: 141.75 dB, instr. constants 1ms: 0.90, 0.5 ms: 2.10. ES transducer: SL+VR: 134.7 dB, instr. constant: 4.47.
Hydrography
Surface temperature was recorded at 4 m depth with a thermograph.
Fishing gear
Bottom trawl: High opening shrimp and fish trawl with net headline 31m (floatline), foot-rope 47m, gear with 12 cm diameter roller disks, 40 m sweeps, estimated headline night 6m and distance between wings during towing 18-20m.
Pelagic trawl: Type "Harstadtrawl", width about 30m, vertical opening 10 - 15m.
Cod ends of trawls with fine meshed inner lining.
Figures giving details of the trawls are attached.
|
Survey assignment DR. FRIDTJOF NANSEN February 1975 to
December 1987 |
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|
Period |
Assignment |
Period |
Assignment |
|
FEB 1975- NOV 1976 |
NW ARABIAN SEA |
APR-DEC 1981 |
WEST-AFRICA |
|
JAN-JUN 1977 |
PAKISTAN |
DEC 1981-APR 1982 |
WEST-AFRICA |
|
AUG 1977-JUN 1978 |
MOZAMBIQUE |
JUN 1982 |
TANZANIA |
|
JUL 1978 |
SEYCHELLES |
AUG 1982 |
KENYA |
|
AUG-SEP 1978 |
SRI LANKA |
SEP-OCT 1982 |
MOZAMBIQUE |
|
APR-JUN 1979 |
SRI LANKA |
NOV-DEC 1982 |
TANZANIA |
|
JUL-AUG 1979 |
OMAN AND ADEN GULFS |
FEB-MAR 1983 |
GULF OF OMAN/ PAKISTAN |
|
SEP-NOV 1979 |
BURMA |
MAY-JUN 1983 |
KENYA/TANZANIA/ MOZAMBIQUE/ MADAGASCAR |
|
NOV-DEC 1979 |
BANGLADESH |
AUG-SEP 1983 |
MALDIVES/PAKISTAN/ IRAN |
|
JAN-FEB 1980 |
SRI LANKA |
NOV-DEC 1983 |
GULF OF OMAN/ OMAN EEZ |
|
MAR-APR 1980 |
BURMA |
JAN-MAR 1984 |
PAKISTAN/S.YEMEN/ SOMALIA/ETHIOPIA |
|
MAY 1980 |
BANGLADESH |
APR-JUN 1984 |
OMAN/IRAN/PAKISTAN |
|
JUN-AUG 1980 |
MALAYSIA/THAILAND/INDONESIA |
AUG-SEP 1984 |
S.YEMEN/SOMALIA/OMAN |
|
SEP-NOV 1980 |
MOZAMBIQUE |
MAR-DEC 1985 |
CONGO/GABON |
|
DEC 1980 |
KENYA |
JAN 1985-JUN 1986 |
ANGOLA |
|
JAN-FEB 1981 |
OMAN AND ADEN GULFS |
AUG-DEC 1986 |
WEST-AFRICA |
|
MAR 1981 |
EGYPT |
FEB-DEC 1987 |
CENTRAL-AMERICA |
|
MAR 1981 |
TUNIS |
|
|
|
APR 1981 |
ALGIER |
|
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