Harbour porpoise Special Area of Conservation seasonal areas

This resource contains shapefiles showing the seasonal components for harbour porpoise Special Areas of Conservation (SACs). The seasonal components for each site reflect the areas and seasons during which harbour porpoise densities are persistently higher. These seasons are relevant with regards to management of human activity.

Three of the sites designated solely for harbour porpoise have only a single seasonal component - either summer or winter which covers the entirety of the SAC boundary ([Bristol Channel Approaches](https://jncc.gov.uk/our-work/bristol-channel-approaches-mpa/ "Bristol Channel Approaches site information centre"); [North Anglesey Marine](https://jncc.gov.uk/our-work/north-anglesey-marine-mpa/ "North Anglesey Marine site information centre"); [North Channel](https://jncc.gov.uk/our-work/north-channel-mpa/ "North Channel site information centre")). The other two sites ([Southern North Sea](https://jncc.gov.uk/our-work/southern-north-sea-mpa/ "Southern North Sea site information centre"); [West Wales Marine](https://jncc.gov.uk/our-work/west-wales-marine-mpa/ "West Wales Marine site information centre")) have both summer and winter components of varying size reflecting changes in usage and distribution with the season. The harbour porpoise sites not included in this shapefile, namely Skerries and causeway and Inner Hebrides and the Minches, are sites showing consistent year-round use. The boundaries from these sites can be obtained from our [SACs with marine components dataset](https://hub.jncc.gov.uk/assets/598a60db-9323-4781-b5a8-dcf0ca3b29f9 "JNCC Special Areas of Conservation with marine components metadata and download page")

The site boundaries were initially drawn up in the British National Grid (BNG) projection in the Secretary of State waters and in Irish National Grid in Northern Ireland waters. Mean Low Water Springs (MLW) was used to delineate the coastal boundary. The MLW shape files were provided by the SNCBs in OSGB36 â British National Grid.

Due to the size and distribution of the proposed sites, an equal area projection was required. European Albers Equal Area Conic (AEAC_UKCS) was used with adjusted standard parallels for the UK Continental Shelf (50.2°N and 61.2°N), which minimises distortion for all sites that span the North-South extent of the UK Continental shelf (47.4 N to approximately 64 N). The transformations used to change projection from BNG to AEAC _UKCS were OSGB _1936 _To _WGS _1984 _Petroleum (appropriate for boundaries which extend 10 km from the coast) and ED _1950 _To _WGS _1984 _18 (appropriate for the modified Albers applied).

本资源包含展示港湾鲸类特设保护区（SACs）季节性成分的形状文件。各地点的季节性成分反映了港湾鲸类密度持续较高的区域和季节。这些季节与人类活动管理密切相关。其中，三个仅针对港湾鲸类的指定地点仅具有单一的季节性成分——夏季或冬季，覆盖整个SAC边界（[布里斯托尔海峡接近地区](https://jncc.gov.uk/our-work/bristol-channel-approaches-mpa/ "布里斯托尔海峡接近地区信息中心