Dataset from SEAPOP's studies on the open sea

The dataset serving as foundation for our analyses of seabird distribution on the open sea is available here. This page will also provide information about the variables constituting the dataset, the sources from which the data are collected and how the data are spread over sea areas, seasons and time periods.

Download the dataset OpenSeaData (CSV 1.7 MB)

The dataset is comprised of so-called "aggregated" data. See the description of data aggregation under Data analysis.

The variables of the dataset

Year, Month, Day of the month, hour of the day (Hrs) and minute (Min) are given as separate variables. XUTM and YUTM give the position of the center of the transects in UTM-coordinates in zone 33. For every point, the number of kilometers of transect is given in the variable DistB. Met indicates the method of observation. Met = 0 indicates normal strip transect method. For species that typically follow vessels, we have in recent years used point observations within the transect at regular intervals. This is denoted as Met = 1. We have corrected for this methodological variation in the analyses. Ocean denotes in which sea area the observation was made: NO = North Sea, NW = Norwegian Sea, BS = Barents Sea. Depth is given in meters. Data are collected from the ETOPO database. For each species, the number of observations of the species is given. The numbers of birds in the air and on the water surface have been aggregated. The species are: ALALL (little auk), ALTOR (razorbill), FRARC (Atlantic puffin), FUGLA (northern fulmar), LACAN (common gull), LAHYP (glaucous gull), LAMAR (great black-backed gull), LAARG (herring gull), RITRI (black-legged kittiwake), MOBAS (northern gannet), URLOM (Brünnich's guillemot), URISP (unidentified guillemot), URAAL (common guillemot).

Data sources

The dataset has been collected from different sources:

The ESAS-database

The dataset from ESAS (European Seabirds At Sea) includes data from the North Sea from 1981 to 2006. Several European research institutions, including NINA, have contributed to the database. All data collected by standardized methods (see above) were extracted from this database.

AKUP and research cruises

In the 1980s and -90s, a number of cruises financed by AKUP (Arbeidsutvalget for konsekvensutredning av petroleumsvirksomhet), were conducted in order to map the occurence of seabirds in the Barents and Norwegian Seas. From 2000 to 2010, a few more specific research cruises were conducted in the same areas. These cruises were financed by the Norwegian Research Council and various oil companies. NINA administrates data from these sources.

SEAPOP cruises

In 2005, SEAPOP started mapping of seabirds in the Barents and Norwegian Seas. The cruises have primarily been conducted as parts of the ecosystem cruises of the Institute of Marine Research (IMR). From 2008, SEAPOP was expanded to include the North Sea. However, the data material gained from cruises in the North Sea through the ESAS cooperation has been regarded sufficient, and thus mapping of the northern ocean areas has been prioritized. See description of each single SEAPOP cruise.

Data sources. Source for data used in analyses of seabird distribution on the open sea.

Data source

Sea area

Time period
Cruise length (km)
ESAS

North Sea

1981-2006

512 072

AKUP/Research cruise

Barents Sea

1983-2004

43 029

 

Norwegian Sea

1984-2000

41 050

SEAPOP cruise

Barentshavet

2005-2011

48 021

 

Norwegian Sea

2005-2011

13 765

Total
   

657 937

Coverage of the study areas

In total, the dataset contains more than 650 000 km of completed transects. However, the data are unequally distributed between sea areas, seasons and time periods. The North Sea was covered well in the 1980s and -90s, whereas the Norwegian Sea is in general poorly covered in autumn and winter.

Cruise lengths. Basis for seabird data collection on the open sea in terms of cruise length by sea area, decade and season. Summer is April 1st – July 31st, autumn is August 1st – October 31st, and winter is November 1st – March 31st.

 
 
Cruise length (km)
Sea area
Time period
summer
autumn
winter
Barents Sea
1980-89
9 163
6 451
5 334
 
1990-99
3 158
688
10 501
 
2000-09
4 907
31 607
4 050
 
2010-11
2 993
8 671
0
 
Sum
20 221
47 417
19 885
Norwegian Sea
1980-89
6 141
2 644
4 261
 
1990-99
16 208
6 077
5 536
 
2000-09
11 248
1 049
216
 
2010-11
0
469
0
 
Sum
33 597
10 239
10 013
North Sea
1980-89
80 067
67 073
67 328
 
1990-99
105 751
71 733
79 728
 
2000-09
12 644
10 437
17 310
 
2010-11
0
0
0
 
Sum
198 462
149 243
164 366
Seasonal maps of the degree of coverage within the study area. Each point represents aggregated observations within a radius of 25 km. © SEAPOP