DOI: 10.5061/dryad.9r76h
title: Data from: Quantifying pursuit-diving seabirds' associations with fine-scale physical features in tidal stream environments

description: The rapid increase in the number of tidal stream turbine arrays will
 create novel and unprecedented levels of anthropogenic activity within
 habitats characterized by horizontal current speeds exceeding 2 ms−1.
 However, the potential impacts on pursuit-diving seabirds exploiting these
 tidal stream environments remain largely unknown. Identifying similarities
 between the fine-scale physical features (100s of metres) suitable for
 array installations, and those associated with foraging pursuit-diving
 seabirds, could identify which species are most vulnerable to either
 collisions with moving components, or displacement from these
 installations. A combination of vessel-based observational surveys, Finite
 Volume Community Ocean Model outputs and hydroacoustic seabed surveys
 provided concurrent measures of foraging distributions and physical
 characteristics at a fine temporal (15 min) and spatial (500 m) resolution
 across a tidal stream environment suitable for array installations, during
 both breeding and non-breeding seasons. These data sets were then used to
 test for associations between foraging pursuit-diving seabirds (Atlantic
 puffins Fratercula arctica, black guillemots Cepphus grylle, common
 guillemots Uria aalge, European shags Phalacrocorax aristotelis) and
 physical features. These species were associated with areas of fast
 horizontal currents, slow horizontal currents, high turbulence, downward
 vertical currents and also hard–rough seabeds. The identity and strength
 of associations differed among species, and also within species between
 seasons, indicative of interspecific and intraspecific variations in
 habitat use. However, Atlantic puffins were associated particularly
 strongly with areas of fast horizontal currents during breeding seasons,
 and European shags with areas of rough–hard seabeds and downward vertical
 currents during non-breeding seasons. Synthesis and applications. Atlantic
 puffins’ strong association with fast horizontal current speeds indicates
 that they are particularly likely to interact with installations during
 breeding seasons. Any post-installation monitoring and mitigation measures
 should therefore focus on this species and season. The multi-species
 associations with high turbulence and downward vertical currents, which
 often coincide with fast horizontal current speeds, also highlight useful
 pre-installation mitigation measures via the omission of devices from
 these areas, reducing the overall likelihood of interactions.
 Environmental impact assessments (EIA) generally involve once-a-month
 surveys across 2-year periods. However, the approaches used in this study
 show that more focussed surveys can greatly benefit management strategies
 aiming to reduce the likelihood of negative impacts by facilitating the
 development of targeted mitigation measures. It is therefore recommended
 that these approaches contribute towards EIA within development sites.
description: orkney_fallofwarness_seabirdenvironmentConcurrent information on seabird distributions and environmental variables at 500m and 15min resolution in the Fall Of Warness, Orkney, UK.FOW_Seabirdenvironment_Data.csv