Cetacean sigthings in North Sea
Marijke N. de Boer
Dataset credit
Marijke N. de Boer
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Contacts
Role | Name | Organization | |
Primary contact |
Marijke de Boer |
Wageningen Marine Research, University of Wageningen |
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Data entry |
Ei Fujioka |
Duke University |
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Citation
Halpin, P.N., A.J. Read, E. Fujioka, B.D. Best, B. Donnelly, L.J. Hazen, C. Kot, K. Urian, E. LaBrecque, A. Dimatteo, J. Cleary, C. Good, L.B. Crowder, and K.D. Hyrenbach. 2009. OBIS-SEAMAP: The world data center for marine mammal, sea bird, and sea turtle distributions. Oceanography. 22(2):104-115.
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Abstract
Minke whales and other marine mammals were recorded in the central North Sea in an area characterised by frontal features and high productivity northeast of the Dogger Bank (4677 km2). Survey efforts were carried out from 28 March to 2 July 2007, at a finer scale than in earlier studies in the region, using 2 vessels as platforms of opportunity and a dedicated line- transect survey vessel following distance sampling methods. The high density of whales indicated that this offshore bank slope is an important spring habitat for minke whales in the North Sea. In total, 77 sightings of minke whales comprising 130 individuals were recorded. The peak density of minke whales was estimated to be 0.029 whales km–2 (minimum estimate, 95% CI: 0.012 to 0.070) in May. During peak abundance, the minke whales temporarily congregated in the area, suggesting that the whales were taking advantage of the local spring abundance of sandeels. The density found was higher than previous studies have suggested for the central North Sea. The results correspond to recent observations of minke whale redistribution within the North Sea, and these may be related to a decline in sandeel availability elsewhere in the North Sea. Offshore banks that aggregate prey may therefore become increasingly important feeding habitats for minke whales and other top predators in the North Sea. The observed habitat preference of minke whales along this offshore bank appeared to be similar to that observed in coastal areas, and this suggests some degree of generality regarding the preference for this type of habitat.
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Purpose
As part of a geophysical seismic survey, marine mammals observations were carried out from three vessels: one seismic vessel, one supply vessel operating well ahead from the seismic vessel. The third vessel, MV ‘Andfjord’, carried out a dedicated Line Transect (LT) survey (23 April to 17 May). The LT vessel was surveying at distances of ≥20 km away from the geophysical vessel and followed predetermined line transects placed randomly in a zigzag pattern in the central (German) part of the survey area.
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Supplemental information
N/A
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References
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Attributes
Overview
This section explains attributes included in the original dataset.
OBIS-SEAMAP restricts the attributes available to the public to date/time, lat/lon and species names/counts
only.
Should you need other attributes described here, you are encouraged to contact the data provider.
Attributes described below represent those in the original dataset provided by the provider.
Only minimum required attributes are visible and downloadable online. Other attributes may be obtained upon provider's permission.
Attributes in dataset
Attribute (table column) | Description |
oid | Unique ID number (generated by OBIS-SEAMAP) |
sighting_number | Sigthing number |
date | Date of the sighting |
time | Time of the sighting at GMT |
vessel | Vessel name |
latitude | Latitude in decimal degrees |
longitude | Longitude in decimal degrees |
sector | Sector |
species | Species name |
latin_name | Scientific name |
sp_tsn | Taxonomic Serial Number added by OBIS-SEAMAP |
total_number | Group size |
beaufort_wind | Beaufort sea state |
geom | Geometry field added by OBIS-SEAMAP |
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OBIS-SEAMAP ID | 2257 |
Seabirds | 0 |
Marine mammals | 165 |
Sea turtles | 0 |
Rays and sharks | 0 |
Other species | 0 |
Non spatial | 0 |
Non species | 0 |
Total | 165 |
Date, Begin | 2007-03-31 |
Date, End | 2007-07-02 |
Temporal prec. | 111110 |
Latitude | 53.15 - 56.26 |
Longitude | 3.08 - 4.58 |
Coord. prec. | 5 decimal digits |
Platform | Boat |
Data type | Animal sighting |
Effort | N/A |
if ($show_effort_stat) {
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Traveled (km) | 0 |
| 0 |
}
if ($sources != null and $sources != "" and $dataset_id != 427) { // Do not show ESAS
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Contr. through | |
}
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Registered | 2023-06-14 |
Updated | 2023-06-15 |
Status | Published |
Sharing policy |
CC-BY-NC (Minimum) |
Shared with |
OBIS
GBIF (via DOI) |
See metadata in static HTML |
See metadata in FGDC XML |
See download history / statistics |
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