SCANS II cetacean sightings from aerial surveys 2005

Sea Mammal Research Unit, University of St. Andrews

Dataset credit

Sea Mammal Research Unit, University of St. Andrews


Primary contact Claire Lacey Sea Mammal Research Unit, University of St. Andrews
Data entry Ei Fujioka Duke University


Lacey, C. 2014. SCANS II cetacean sightings from aerial surveys 2005. Data downloaded from OBIS-SEAMAP ( on yyyy-mm-dd.
Hammond, P.S., Macleod, K., Berggren, P., Borchers, D.L., Burt, L., Cañadas, A., Desportes, G., Donovan, G.P., Gilles, A., Gillespie, D., et al. 2013. Cetacean abundance and distribution in European Atlantic shelf waters to inform conservation and management. Biological Conservation. 164, 107–122.


The European Union (EU) Habitats Directive requires Member States to monitor and maintain at favourable conservation status those species identified to be in need of protection, including all cetaceans. In July 2005 we surveyed the entire EU Atlantic continental shelf to generate robust estimates of abundance for harbour porpoise and other cetacean species. The survey used line transect sampling methods and purpose built data collection equipment designed to minimise bias in estimates of abundance. Shipboard transects covered 19,725 km in sea conditions 6Beaufort 4 in an area of 1,005,743 km2. Aerial transects covered 15,802 km in good/moderate conditions (6Beaufort 3) in an area of 364,371 km2. Thirteen cetacean
species were recorded; abundance was estimated for harbour porpoise (375,358; CV = 0.197), bottlenose dolphin (16,485; CV = 0.422), white-beaked dolphin (16,536; CV = 0.303), short-beaked common dolphin (56,221; CV = 0.234) and minke whale (18,958; CV = 0.347). Abundance in 2005 was similar to that estimated in July 1994 for harbour porpoise, white-beaked dolphin and minke whale in a comparable area. However, model-based density surfaces showed a marked difference in harbour porpoise distribution between 1994 and 2005. Our results allow EU Member States to discharge their responsibilities under the Habitats Directive and inform other international organisations concerning the assessment of conservation status of cetaceans and the impact of bycatch at a large spatial scale. The lack of
evidence for a change in harbour porpoise abundance in EU waters as a whole does not exclude the possibility of an impact of bycatch in some areas. Monitoring bycatch and estimation of abundance continue to be essential.



Supplemental information

[2020-09-30] The following invalid species names were corrected according to the Integrated Taxonomic Information System (ITIS).
Turtles: Testudines (173749) => Testudines (948936)

Data from three teams aboard different airplanes were merged. Teams are flagged 'A', 'B' and 'C' in 'computer' attribute.




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
oidUnique ID number (generated by OBIS-SEAMAP)
ltdefinition not provided
sighting_nSighting number
transect_nTransect number
flight_noFlight number
obs_datetimeDate and time of observation in local time calculated by OBIS-SEAMAP
datetime_utcDate and time of observation in UTC
observerObserver ID
dec_angleVertical angle in degrees
sp_obsSpecies name recorded
sp_tsnTaxonomic Serial Number added by OBIS-SEAMAP
obs_countbest estimate of number of animals
cueRecord of the initial cue for the sighting
swim_direcSwim direction
dist_alongdefinition not provided
perp_distPerpendicular distance to the animal sighted
xtedefinition not provided
other_tmdefinition not provided
other_xtedefinition not provided
latitudeLatitude in decimal degrees
longitudeLongitude in decimal degrees
orig_pod_sPod size originally recorded
sideSide of the airplane (L or R)
calvesNumber of calves
computerComputer (also identifier of the team)
geomGeometry field added by OBIS-SEAMAP
Marine mammals741
Sea turtles2
Rays and sharks5
Other species90
Non spatial0
Non species2,277
Date, Begin2005-06-27
Date, End2005-08-04
Temporal prec.111111
Latitude0.00 - 61.94
Longitude-10.75 - 9.90
Coord. prec.5 decimal digits
Data typeAnimal sighting
EffortYES (ID: 1154)
Traveled (km)30,144
Effort hours210
Contr. through
Sharing policy CC-BY-NC (Minimum)
Shared with OBIS
GBIF (via DOI)
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See metadata in FGDC XML
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