Occupancy patterns of sea birds in relation to oceanographic conditions at sites on the Llŷn Peninsula

Abstract

With the current increase in the emergence of offshore renewable energy installations it is becoming increasingly important to monitor and study seabird populations. In order to understand the potential impacts of these installations we must first understand the spatial and temporal factors affecting seabirds site usage which may then inform future monitoring and management. In this study a series of shore based surveys were carried out to assess the occupancy patterns of seabirds in relation to oceanographic conditions at three sites along the Llŷn peninsula. One site, named Bardsey Sound is a proposed site for tidal energy extraction due to fast current speeds moving through the area, compared with the two other sites with slower average current speeds recorded. Statistical analysis was carried out on the collated data to identify differences in sightings between the three locations, as well as differences in the number of sightings associated with tidal phase. The results of the study show significant differences between the number of seabird sightings at the three locations, specifically that total seabird sightings, kittiwake and razorbill sightings were significantly different at Porth Dinllaen, to Porth Colmon and Bardsey Sound. A relationship with the tidal phase could not be deduced from this study and future work should focus on looking at these relationships to inform the safe operation of the potential tidal turbine. This would ensure minimum effect on surrounding seabird populations. However, this study is successful in showing an initial insight into how seabirds are using the sites in this area, the possible reasons for these preferences and provides a foundation for future research.