Cetacean sigthings in North Sea

Marijke de Boer

doi:10.15468/4dwedf

Cetacean sigthings in North Sea

Citation

de Boer M, OBIS-SEAMAP (2023). Cetacean sigthings in North Sea. OBIS-SEAMAP. Occurrence dataset https://doi.org/10.15468/4dwedf accessed via GBIF.org on 2024-12-13.

Description

Original provider: Marijke N. de Boer Dataset credits: Marijke N. de Boer 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. 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.

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.

Sampling Description

Study Extent

NA

Sampling

NA

Method steps

NA

Additional info

marine, harvested by iOBIS

Taxonomic Coverages

Scientific names are based on the Integrated Taxonomic Information System (ITIS).

Lagenorhynchus acutus
common name: Atlantic white-sided dolphin rank: species
Tursiops truncatus
common name: Common bottlenose dolphin rank: species
Phoca vitulina
common name: Harbor seal rank: species
Halichoerus grypus
common name: Atlantic gray seal rank: species
Phocoena phocoena
common name: Harbor porpoise rank: species
Megaptera novaeangliae
common name: Humpback whale rank: species
Balaenoptera acutorostrata
common name: Common minke whale rank: species
Phocidae
common name: Earless seals rank: family
Cetacea
common name: Cetaceans rank: order
Delphinidae
common name: Dolphins rank: family
Cetacea
common name: Cetaceans rank: order
Lagenorhynchus albirostris
common name: White-beaked dolphin rank: species
Lagenorhynchus
common name: White-beaked dolphins rank: genus

Geographic Coverages

North Sea

Bibliographic Citations

Contacts

Marijke de Boer
originator
position: Primary contact
Wageningen Marine Research, University of Wageningen
email: marijkedeboer@hotmail.com

OBIS-SEAMAP
metadata author
Marine Geospatial Ecology Lab, Duke University
A328 LSRC building
Durham
27708
NC
US
email: seamap-contact@duke.edu
homepage: https://seamap.env.duke.edu

OBIS-SEAMAP
distributor
Marine Geospatial Ecology Lab, Duke University
A328 LSRC building
Durham
27708
NC
US
email: seamap-contact@duke.edu
homepage: https://seamap.env.duke.edu

Marijke de Boer
owner
position: Primary contact
Wageningen Marine Research, University of Wageningen
email: marijkedeboer@hotmail.com

Marijke de Boer
administrative point of contact
position: Primary contact
Wageningen Marine Research, University of Wageningen
email: marijkedeboer@hotmail.com