Location & Description
Strangford Lough is a unique and diverse ecosystem located in Northern Ireland. With a length of 30km and a width of up to 8km, this large shallow sea Lough is connected to the open sea by the narrow Strangford Narrows, which has strong currents of up to 8 knots. The Lough’s physical characteristics, including its tides, wave action, water quality, underlying geology, and location, create a complex mosaic of habitats and species, making it a vital part of Northern Ireland’s Natural Capital.
Location
Strangford Lough is on the east coast of County Down, Northern Ireland. Its northern end lies some 15km east of central Belfast (6km from the outskirts) while Downpatrick lies 5km west of the southwest corner. Almost land-locked, the Lough is separated from the Irish Sea by the Ards Peninsula to the east and is bounded to the south by the Lecale coast.
The southern boundary of the SAC and SPA extends from Killard Point; across the Strangford Narrows to Ballyquintin Point; At the estuary of the Comber River the SAC boundary ends; the SPA boundary extends beyond this to include the primarily freshwater area of the Quoile Pondage National Nature Reserve.
The MCZ includes the SAC and SPA (excluding the Quoile Pondage area) but extends outside Strangford Lough to Kearney village on the northern side and Sheepland Coast on the southern side. The MCZ also goes to High Mean Water Mark
Description
Strangford Lough is a large (approximately 150km2) shallow sea Lough, of which approximately 50km2 lies between high and low water mark. The Strangford Narrows, an 8km long channel with a minimum width of 0.5km, connects it to the open sea. This narrow entrance channel has extremely strong currents of up to 8knots (4m/s). The Lough is 30km long from head to mouth and up to 8km wide.
The varied patterns of tides, wave action, water quality, underlying geology, and location create the conditions for a complex mosaic of habitats and species in the Lough. Its coastal and marine species and habitats are vastly important for biodiversity and are a significant part of Northern Ireland’s Natural Capital.
The tidal flats of Strangford Lough form extensive areas around the northern and north eastern shorelines. They are surrounded to the north east by sea defences for the town of Newtownards and the A20 coastal road that runs along much of the Lough’s eastern shoreline, from Newtownards to Portaferry.
The main characteristic of the MPA is the sea inlet of Strangford Lough itself. This sea inlet emerged from under the melting ice-sheets of the Ice Age and is for the most part less than 10m in depth. There is a deeper Y-shaped channel (possibly an old river-valley or geological fault-line) up to 66m deep which extends from the Strangford Narrows up the central portion of the Lough. The other arm of the “Y” goes towards Kircubbin.
The bedrock is largely greywacke sandstones and shales of Silurian age. The Lough has an indented shoreline and a great variety of subtidal and intertidal habitats. The west shore has numerous islands typical of flooded drumlin topography. Pladdies, found mainly along the more exposed eastern shore, are eroded drumlins covered at high tide.
The physical regime of the Lough, with its high-water quality, complex current systems and varying topography, substrata and water depths, is hugely important to the overall ecosystem.
The nature of the sediments of the shore and seabed are predominantly determined by a combination of the geological history along with the tides, currents, and exposure to wave action. In general, there is a gradation from bedrock, through cobble, gravel and sand to mud, from the Narrows, moving both into the body of the Lough and offshore into the Irish Sea. There are extensive areas of mudflat and sandflats mainly at the northern end of the Lough. There are also areas of saltmarsh, the most extensive being in the Comber River estuary. The gradation of sediments is also influenced by the effects of shelter and currents around islands and pladdies.
The water in the Lough is fully saline except at the mouths of the two moderate-sized rivers, the Comber (in the northwest) and the Quoile (in the southwest), and where several streams drain into the Lough at various points from the catchment (an area approximately 900km2), where it may be somewhat brackish. The area has a mild climate with relatively low rainfall compared with other areas of Ireland, infrequent frosts and prevailing west to southwest winds.
Strangford Lough supports a diverse range of marine habitats and communities with over 2,000 recorded species. It is important for marine invertebrates, algae and saltmarsh plants, for wintering and breeding wetland birds, and for marine mammals.
The extensive intertidal mudflats and sandflats are the feeding grounds for internationally important numbers of overwintering birds. Strangford Lough attracts up to 80% of the Canadian population of pale bellied Brent geese through October/November, along with internationally significant populations of Knot, Redshank, Bar-tailed godwit, Golden plover and Shelduck (over 70,000 water birds). Nationally important populations utilising the Strangford Lough area include Turnstone and Ringed Plover as well as 11 other species of birds.
The Lough’s islands provide nesting sites for terns that travel from the Antarctic and feed on small fish during the summer months. These islands also provide key haul out areas for Harbour (Common) seals with Strangford Lough as one of the UK and Ireland’s most important breeding sites for this species.
Several notable maritime vegetation communities occur. Seventeen rare plant species have been recorded. Saltmarsh is a rare habitat in Northern Ireland but within the Strangford Lough and Lecale area there are some of the best examples.
Submerged gullies are found at the mouth of the Lough and provide habitat for a diverse range of marine flora and fauna.
Land usage in the catchment is approximately 90% agricultural land (pastures, complex cultivation patterns and agriculture/natural vegetation). The main coastal settlements are Newtownards, Downpatrick and Comber. Smaller towns and villages include Greyabbey, Kircubbin, Portaferry, Killyleagh, Strangford, Kilclief and Ballyhornan with several smaller communities scattered between these areas.
