Data from: Distribution maps of cetacean and seabird populations in the North-East Atlantic

Distribution maps of cetaceans and seabirds at basin and monthly scales
are needed for conservation and marine management. These are usually
created from standardised and systematic aerial and vessel surveys, with
recorded animal densities interpolated across study areas. However, as
individual surveys have restricted spatial and temporal coverage,
distribution maps at basin and monthly scales have previously not been
possible. This study develops an alternative approach consisting of (1)
collating diverse survey data to maximise spatial and temporal coverage,
(2) using detection functions to estimate variation in the surface area
covered (km2) among these surveys, standardising measurements of effort
and animal densities, (3) developing species distribution models (SDM)
that overcome issues with heterogeneous and uneven coverage. 2.68 million
km of survey data in the North-East Atlantic between 1980 and 2018 were
collated and standardised. SDM using Generalized Linear Models (GLM) and
General Estimating Equations (GEE) in a hurdle-model were developed.
Distribution maps were then created for 12 cetacean and 12 seabird species
at 10 km and monthly resolution. Qualitative and quantitative assessments
indicated good model performance. This study provides the largest-ever
collation and standardisation of diverse survey data for cetaceans and
seabirds and the most comprehensive distribution maps of these taxa in the
North-East Atlantic. These distribution maps have numerous applications
including the identification of important areas needing protection and the
quantification of overlap between vulnerable species and anthropogenic
activities. This study demonstrates how the analysis of existing and
diverse survey data can meet conservation and marine management needs.