Towards improved conservation of the east coast of Scotland bottlenose dolphin population: quantifying and understanding a major range expansion into

*northeast England.

The east coast bottlenose dolphin (Tursiops truncatus) population has been studied since 1989 as part of a collaborative project focused in two main study areas, the Moray Firth Special Area of Conservation (SAC) and the Tay estuary and adjacent waters (e.g. Cheney et al. 2018, Arso Civil et al. 2019). The population is currently undergoing a major range expansion from Scotland into northeast England, as indicated from public sightings and citizen science photographic data. However, the lack of empirical data on abundance and distribution of animals south of the Scottish-English border represents a challenge to assessing the conservation status of this protected population, as required by law under respective Habitats Regulations in England (2017) and Scotland (1994). Furthermore, this data gap prevents adequate assessment of potential threats such as offshore wind developments which are increasing along the east coast of the UK. Levels of connectivity throughout the increased distributional range remain unknown, as do understanding of any individual variation in movements and ranging patterns, and how these relate to changes in overall distribution or social structure. Determining the causes of a population range expansion is challenging. This project aims to improve knowledge and understanding of this through a multi-disciplinary approach. Firstly, the distribution and abundance of animals in northeast England needs to be established, based on new data from dedicated boat surveys. This will enable investigation of levels of connectivity between England and Scotland to better understand movements between different areas within the range, and to characterise which animals are utilizing habitat south of Scotland. This project will also seek to understand whether aspects of population dynamics such as temporal and spatial variation in age structure and growth rates can partly explain this recent phenomenon. The shifting nature of this population's distributional range in addition to uncertainty surrounding UK environmental law post-Brexit pose questions for the successful management of this protected species. A comprehensive review of the relevant literature and policy will be undertaken to assess current management and to propose how the quantitative outputs from this project can shape future policy for the east coast bottlenose dolphin population, and for mobile marine species in general.

Refs:
Arso Civil M, Quick NJ, Cheney B, Pirotta E, Thompson PM and Hammond PS (2019). Changing distribution of the east coast of Scotland bottlenose dolphin population and the challenges of area-based management. Aquatic Conservation: Marine and Freshwater Ecosystems, 29,178-196.
Cheney B, Graham IM, Barton TR, Hammond PS and Thompson PM (2018). Site condition monitoring of bottlenose dolphins within the Moray Firth Special Area of Conservation: 2014- 2016. Scottish Natural Heritage Research Report No. 1021. Inverness, UK: Scottish Natural Heritage.