SCANS II cetacean sightings on primary platform of vessel 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



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 <= Beaufort 4 in an area of 1,005,743 km2. Aerial transects covered 15,802 km in good/moderate conditions (<= Beaufort 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

Surveys from seven different vessels were merged. Each vessel contained two sightings platforms running concurrently – primary and tracker. This dataset includes sightings from the primary platform. Sightings from the tracker platform are registered in SCANS II cetacean sightings on tracker platform of vessel surveys 2005.

Effort or vessel tracks for these surveys are provided with this dataset. Survey conditions such as sea state, glare, swell, wind are found in the effort data.

In the primary platform, normal binoculars were used and distance and angle were estimated by observer on the vessel with raditional bearing board and range finder-stick.


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.



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)
gpsindexGPS index
obs_dateDate of observation
obs_timeTime of the observation (local time zone converted from UTC by OBIS-SEAMAP)
datetime_utcTime of the observation (UTC)
sightingnumberSighting number
estimatedangleEstimated angle
radialdistanceEstimated radial distance
sp_obsSpecies name recorded
sp_tsnTaxonomic Serial Number added by OBIS-SEAMAP
multispeciesFlago of multiple species
lownumberLow number of number of animals
obs_countbest estimate of number of animals
highnumberHigh number of number of animals
calvesNumber of calves
cueRecord of the initial cue for the sighting
aspectvalueAspect value
duplicatestatusDuplicate status
duplsightingnoDuplicate sighting number
observerObserver ID
transectTransect number
latitudeLatitude in decimal degrees
longitudeLongitude in decimal degrees
transect_originalTransect original
ik_effdefinition not provided
pdistdefinition not provided
timesseendefinition not provided
vessel_codeVessel code
geomGeometry field added by OBIS-SEAMAP
Marine mammals950
Sea turtles1
Rays and sharks23
Other species37
Non spatial0
Non species0
Date, Begin2005-06-29
Date, End2005-07-28
Temporal prec.111111
Latitude35.96 - 61.99
Longitude-11.93 - 12.60
Coord. prec.5 decimal digits
Data typeAnimal sighting
EffortYES (ID: 1151)
Traveled (km)20,078
Effort hours1,092
Contr. through
Sharing policy CC-BY-NC (Minimum)
Shared with OBIS
GBIF (via DOI)
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