Assessing harbour porpoise populations in south-west Wales, data issues and implications for conservation and management J.A. Oakley a, * , R.E. Jenkins a , T. Thomas a , A.T. Williams a, b , M.R. Phillips a a Coastal and Marine Research Group, University of Wales Trinity Saint David (Swansea), Mount Pleasant, Swansea, Wales, SA1 6ED, UK b CICA NOVA, Nova Universidade de Lisboa, Lisboa, Portugal article info Article history: Received 25 June 2015 Received in revised form 17 September 2015 Accepted 22 September 2015 Available online xxx Keywords: Harbour porpoise Phocoena phocoena Cetacean SAC Swansea bay Gower South Wales Calves Distribution Marine renewable energy abstract The UK Government was recently criticised for failing to fulfil its obligations under the Habitats Directive in respect of designating protected areas for Harbour Porpoise Phocoena phocoena. At the centre of the discussion lay the stringent nature of the qualifying criteria for site selection. Concurrently, there is a growing support for marine renewable energy technologies; however the planning process is often hampered by inadequate marine data to enable appropriate siting or mitigation against potential ecological impacts. The Bristol Channel region's physical environment is a suitable source for the gen- eration of marine renewable energy, and the world's first tidal lagoon will be sited in Swansea Bay. A 10 year dataset was collected, analysed and compared against the qualifying criteria for a Special Area of Conservation (SAC). Results revealed that a resident population of porpoise existed and density values of 0.58 hp km 2 were comparable with other UK regions. While an insignificant calf adult ratio of 1:13 was recorded, breeding and nursery areas were identified. Analysis highlighted a number of hotspots of porpoise activity, suggesting that these areas are critical habitats, particularly for feeding and foraging. Such information will enable future marine renewable energy developers to select the most appropriate sites. It is argued that existing SAC qualifying criteria prevents recognition of critical habitats for the harbour porpoise and a case is made for an eastward extension of a proposed harbour SAC to include Swansea Bay and the south Gower coast. This paper demonstrates that cetacean data is sparse and even though this study has filled important knowledge gaps, there is still a need for further research. This research would enable both developers and planners to adequately and appropriately consider future marine renewable energy projects. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction Harbour porpoise Phocoena phocoena are protected under the Habitats and Species Directive (92/43/EEC) and listed as a priority species in UK Biodiversity Action Plans (UKBAP; Jenkins, 2007). They are the smallest marine mammal found in UK waters and even though they occur offshore, are more typically sighted in coastal areas (Jenkins, 2007). Often associated with near-shore headlands and strong tidal currents, porpoise are commonly observed within shallow bays, estuaries and narrow tidal channels (Pierpoint, 2008; Baines and Earl, 1999). Their small size, shy nature, lack of clearly identifiable markings and highly mobile, wide ranging nature make harbour porpoise difficult to observe. These characteristics make data collection challenging, which in turn has contributed to a lack of protected areas being identified in the UK (Embling et al., 2009). Dolman et al. (2013) identified 10 sites where sufficient evi- dence existed to undertake protective measures. In Wales, these sites included north Pembrokeshire, south Cardigan Bay, Lleyn Peninsula, Bardsey Island, and north and west Anglesey. However, there has been criticism that policy makers provide frameworks designed to support and conserve species, but make qualifying criteria too restrictive or inadequately defined, creating loopholes and inconsistencies (Pinn, 2010). To ascertain whether harbour porpoise, currently a species of conservation priority, is at Favourable Conservation Status, it is necessary to monitor annual trends in numbers and distribution over a sufficient time scale, in order to test statistical significance. However, research data is limited, particularly in South Wales, and * Corresponding author. E-mail addresses: Judith.Oakley@uwtsd.ac.uk (J.A. Oakley), Rhian.Jenkins@ uwtsd.ac.uk (R.E. Jenkins), tony.thomas@uwtsd.ac.uk (T. Thomas), allan.williams@ uwtsd.ac.uk, Allan.williams@virgin.net (A.T. Williams), mike.phillips@uwtsd.ac.uk (M.R. Phillips). Contents lists available at ScienceDirect Ocean & Coastal Management journal homepage: www.elsevier.com/locate/ocecoaman http://dx.doi.org/10.1016/j.ocecoaman.2015.09.011 0964-5691/© 2015 Elsevier Ltd. All rights reserved. Ocean & Coastal Management 119 (2016) 45e57