Observatoire Pelagis boat surveys 2003-2021

Observatoire PELAGIS UAR 3462 University La Rochelle - CNRS

Dataset credit

Observatoire PELAGIS UAR 3462, University La Rochelle - CNRS


Primary contact Ghislain Doremus Observatoire Pelagis UMS 3462, University La Rochelle - CNRS
Secondary contact Hélène Peltier Observatoire PELAGIS, UMS 3462, University La Rochelle-CNRS
Data entry Ei Fujioka Duke University



Since 2003, the Observatoire PELAGIS (La Rochelle University) participated to annual halieutic surveys, led by the IFREMER, to collect data on the distribution of marine top predators in order to estimate their relative abundance and preferred habitats in the Bay of Biscay, the Channel and the North Sea.
Each year, three observers take place on board the vessel “Thalassa” to record sightings of seabirds, marine mammals, large fish and fishing boats, from dawn to dusk. Following distance sampling methods, visual censuses are made by two observers (while the third observer is resting) from the upper platform of the boat (min. 14m above the sea level). They are placed on each side of the deck, looking ahead for marine predator with an angle of 180°. For each sighting, the species and the number of individuals are recorded, as well as the behaviour, distance and angle (upon request).


One of the main advantages of this survey lays in its ecosystemic approach, which provides information on all the components of the food web (from planktonic organisms to predators) as well as data on the environmental parameters (sea surface temperature, salinity…). Interactions between prey and predators are complex in marine ecosystems, which are submitted to strong spatio-temporal variations. Thanks to ecosystem-based surveys, observed distributions and densities of marine predators can be related to the occurrence of their prey, providing to scientists and managers a better understanding of the marine ecosystems structure.

Supplemental information

[2022-10-20] The records on 2016-09-21 got the longitude sign swapped. they are corrected.
[2022-01-18] Data in 2020 and 2021 were appended.
[2018-04-26] Data in 2016 and 2017 were appended.

Time and group size of the sightings are not available online. They may be released upon request.


Doremus, G. 2022. Observatoire Pelagis boat surveys 2003-2021. Data downloaded from OBIS-SEAMAP (http://seamap.env.duke.edu/dataset/1403) on yyyy-mm-dd.



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)
cdnomdefinition not provided
latitudeLatitude in decimal degrees
longitudeLongitude in decimal degrees
speciesSpecies name recorded
sp_tsnTaxonomic Serial Number added by OBIS-SEAMAP
surveySurvey name
observerObserver name
data_producerData producer
data_administratorData administrator
obs_dateDate of the observation (time is not available)
obs_timeTime of the observation is not available
obs_countGroup size is not available.
geomGeometry field added by OBIS-SEAMAP
Marine mammals4,667
Sea turtles47
Rays and sharks138
Other species3,377
Non spatial0
Non species28
Date, Begin2003-05-29
Date, End2021-12-05
Temporal prec.111000
Latitude-25.61 - 55.28
Longitude-11.29 - 47.36
Coord. prec.6 decimal digits
Data typeAnimal sighting
Traveled (km)0
Contr. through
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